JPS58108526A - Flat particle silver halide emulsion - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of the Invention The present invention is useful in the field of photography. The present invention relates to tabular grain silver halide emulsions comprising a dispersion medium and silver halide grains.

(2) Prior art In tabular silver halide grain silver halide photography, a radiation-sensitive emulsion is used, and such an emulsion consists of a dispersion medium, usually gelatin, and a radiation-sensitive radiation @7% embedded therein. A variety of regular and irregular grain shapes have been observed in silver halide photographic emulsions, which consist of microcrystals (known as grains) of silver halodide. Regular grains are often cubic or octahedral; zero grain edges may exhibit rounding due to ripening effects. In addition, in the presence of a strong ripening agent such as ammonia, these particles become spherical or thick plate-like near spheres9. This means that, for example, Rand (
U.S. Pat. je) J Focal Siles, 1964, pp. 221
-223. Rods and tabular grains are often observed in varying proportions among other grain shapes. This is especially true when the pAg (the reciprocal of the logarithm of the silver ion concentration) of the emulsion changes with the exit of precipitate formation, as seen, for example, in single-jet precipitation methods. Although widely studied, these particles are mostly macro-sized and cannot be used in photography.

Tabular grains are defined as tabular grains, each of which is substantially larger than any other single crystal face of the grain! A particle with two parallel crystal planes that are almost parallel.

High 7 spectral ratio tabular grain silver bromide emulsions, in which the 7 spectral ratio (i.e. the ratio of diameter to thickness) of the tabular grains is substantially greater than 1=1, are available from Cagnae and Chat@au. Evolution of morphology of silver bromide crystals during physical ripening
Kagole Forge Ode Sil/Quantity - Bromide Crystals Dueling Fidustrie Photography, Volume 33% A2 (1962), pp, 121-1
2! As reported in
It was sold under the name 133. This product had a sulfur sensitized silver bromide emulsion coating on opposite major sides of the film support.

This emulsion was not spectrally sensitized because it was intended for exposure to X-rays. Tabular grains have an average aspect ratio of about 5 to
7:1. The tabular grains accounted for more than 50% of the projected area of the grains, and the non-tabular grains occupied more than 25% of the projected area. When these emulsions are replicated several times, the emulsion with the highest average aspect ratio of the several replicates has an average tabular grain diameter of 2.5.
micrometers, an average tabular grain thickness of 0.36 micrometers and an average aspect ratio of 7:1. Other replicate emulsions were thicker, larger diameter tabular grains with lower average aspect ratios.

Although tabular grain silver bromoiodide emulsions are known in the photographic industry, none are known that exhibit a high average aspect ratio.
in) Photographic Emulsion Chemistry, Focal Press, 196
6, pp, 66-72 and Triperi (Triv*11
1) and the influence of silver iodide on the structure of the bromoiodide precipitate series of soot and soot (8m1th),” De Fotografie, Re-Journal, Vol. LXXX, July 1940, p.
p, 285-288. Tripeligi and Smith observed a significant reduction in both grain size and aspect ratio (with the introduction of iodide). Gutov
"Nucleation and Growth Rate in the Precipitation Formation of Silver Halodanide Photographic Emulsions", Photographic Sciences and Engineering, Vol. 14, 16
4. July-August 1970, pp. 24B-257, reports the preparation of silver bromide and silver bromoiodide emulsions of the type prepared by single jet precipitation using a continuous precipitation apparatus. There is.

Side I techniques of emulsions in which the major portion of the silver halide is present in tabular grain form have been described in recent publications. U.S. Pat. No. 4,063,951 discloses a tabular crystalline silver halide bounded by (Zoo) cubic faces and having a cut ratio (based on edge length) of 1.5 to 7:1. The tabular grains exhibited the characteristics of square and rectangular major faces (Zoo) crystal planes.U.S. Pat. Ostwald ripening increases the size of the seed crystals,
The halogenated crystals are predominantly twinned octahedral crystals by controlling pBr (the reciprocal of the logarithm of the bromide ion immersion degree) and completing grain growth without re-nucleation or Ostwald ripening. The preparation of silver emulsions is described. U.S. Patent No. 4,150,994;
184,877 and 4,184,878, British Patent No. 1,570,581 and German Patent Publication No. 2,905,655 and German Patent No. 2,921,07
No. 7 teaches the use of seeds in which at least 90 moles of iodide are used to form flat twinned octahedral silver halide grains. Here, unless otherwise specified, all halide percentages are based on the silver present in the corresponding emulsion, grain, or grain region, e.g.
A grain of silver bromoiodide containing 90 moles of iodide contains 10 moles of bromide. Some of the above references report emulsions with increased coverage/extensibility and illustrate their usefulness as both black and white and color camera films. U.S. Patent No. 4,
No. 063,951 specifically reports that the upper limit of the Asu RjF ratio is 7=1, but the example only describes a very low aspect ratio of 2:1. First, it is considered that the 7:1 aspect ratio described in this specification is actually about 3. From repeated examples and published micrographs, the spectral ratio found in other above-mentioned references is less than 7:1.

JP-A-55-142329 (publication date: November 6, 1980) is thought to have substantially the same teachings as U.S. Pat. No. 4,150,994, but silver iodide Although not limited to the use of seed grains, this publication specifically mentions the formation of tabular silver chlorobromide grains containing less than 50 moles of chloride. Examples of such surface emulsions should be specifically shown, however, considering the information provided, it is clear that in the case of this publication, a relatively low proportion of tabular silver halide grains are obtained; The 7 spectral ratio of the particles is described in U.S. Patent No. 4,
It is clear that it is not larger than that of No. 150,994.

B. Composite silver halide grains The advantages of independent silver halide grains can be expressed as a single composite silver halide grain.
f, a The combination of multiple halides to achieve this in a silver anodic grain structure is recognized in the art and, although not recognized, has been used early in the art. has been done.

German Patent No. 505 issued on August 12, 1930
, 012 teaches the formation of silver halide emulsions that are green in color after development. This can be accomplished by precipitating the iron halide under conditions which involve the sequential introduction of potassium iodide and sodium chloride; testing of emulsions prepared by this method shows that small silver iodide grains (
It can be seen that an average diameter of substantially less than 0.1 micrometer) is formed. Independent silver chloride grains were formed, and from the electron micrograph, the silver chloride grains were also engineered.
It can be seen that it is precipitated on silver iodide grains by taxial growth. As the iodized steel particles increase in size, a resulting color change occurs from the desired green tone to a brown tone. The teachings of German Patent No. 505,012 essentially overlap with the teachings of Photography, Chez Industrie
Indumtri*)sr Green-and Brown-D*v*1
Oplng Emulsioms) J, Volume 34,
pp, 764766 and 872. July 8 and August 5, 1938 - Flj.

included in.

British Patent No. 1,027,146 discloses a technique for forming composite silver halide grains. A core or core grain of iron halide is formed and then coated with one or more adjacent silver halide emulsions 1-. Such composite silver halide grains contain silver chloride, silver bromide, silver iodide, or a mixture thereof.

For example, a silver bromide core can be coated with a layer of silver chloride or a layer of a mixture of silver bromide and silver iodide; A layer of silver can be included. British Patent No. 1,027,146 teaches that depositing silver chloride on bromide provides the spectral response to silver bromide and the development characteristics of silver chloride. No. 3,505,068, British Patent No. 1.
The teachings of No. 027,146 are used to prepare a slow emulsion layer to be used in combination with a fast emulsion layer to achieve relatively low dye image contrast. The silver halide grains used in the low-speed emulsion layer have a core consisting of silver iodide or silver halide iodide and a shell containing no iodide and consisting of, for example, silver bromide, silver chloride or silver chlorobromide. ing. U.S. Patent No. 4,094,68
No. 4 discloses the deposition of silver chloride by epitaxial growth on silver iodide in the form of a truncated piebilla f, do (hexagonal structure of wurtzite taig). According to this patent, through the use of composite grains, both the light absorption properties of silver iodide and the functional properties of silver chloride can be achieved. U.S. Pat. No. 4,142,900 is essentially similar to the aforementioned U.S. patent, but states that silver chloride is converted to silver bromide by a conventional halide conversion process after deposition by epitaxial growth. They differ in some respects.

UK Patent Application No. 2,053,499A is U.S. Patent No. 4
．． Although essentially similar to No. 142,900, this British application involves direct epitaxial growth of silver bromide on silver iodide. Two horns 41f,
Patent Application No. 0019917 (Publication date: December 1980 to EI) discloses that silver halide containing less than 10 mol of iodide is epitaxially grown on silver halide grains containing 15 to 40 mol of iodide. The disclosure discloses that the substance is deposited.

U.S. Patent No. 3,804,629 is physically aged;
A silver chloride emulsion is then added to the washed emulsion prior to chemical ripening of the emulsion, or physically aged, and the silver chloride is precipitated onto the washed silver halide emulsion to remove dust, particularly metal dust. It is disclosed that the stability of silver halide emulsion layers against adverse surface effects can be improved. This US patent also discloses that the silver chloride thus deposited will form hllloaks on the previously formed silver bromide grains.

Berry (B@rr)r) and Skill My (Skllll)
"Surface structure and epitaxial growth on rAgBr microcrystals", Journal of Abrad Physics, Vol. 35, A7. July 1964, PP
, Tables 2165-21690 disclose the growth of silver chloride on silver bromide. The MgBr octahedra form growths over their entire surface and have an even greater reactivity 2 than the cubes. The reaction occurs mainly at the corners and edges of the cube. In the case of twinned tabular crystals, it has been observed that they release growths distributed in runs on their main crystal faces, and that the growth near their edges is slightly more advanced. ing. In addition, the emulsion coating can form linearly aligned growths after being bent, also indicating the influence of slipbands.

C1 sensitivity (speed), graininess and during sensitized imagewise exposure,
The latent image center, which makes the entire particle selectively developable, can be formed through the absorption of very small amounts of radiation, and provides unusually high sensitivity capabilities compared to many alternative imaging methods. Whether or not it can be applied to silver halide photographs depends on the possibility of forming latent image centers. Various chemical sensitizations, such as noble metals (e.g. gold), intermediate carbon (eg, using sulfur and/or selenium) and reduction sensitization have been developed and can be used alone or in combination to improve the sensitivity of silver halide emulsions.

When chemical sensitization exceeds the best level, capri (minimum concentration)
increases rapidly, resulting in a rapid loss of image discrimination (maximum density minus minimum once) and thus a relatively small increase in sensitivity. Optimal chemical sensitization is the best balance between sensitivity, image discrimination, and minimum density for a particular photographic application.

Normally, the sensitivity of silver halide emulsions is only negligibly exceeded in the spectral range of their inherent sensitivity by chemical sensitization. As the concentration of the spectral sensitizer increases at an optimum value, the sensitivity of the emulsion increases beyond its native sensitivity region and generally declines rapidly thereafter, 1067-1069).

Within the range of silver halide grain sizes normally found in photographic elements, the maximum sensitivity obtained during best sensitization is currently available at 6 grains, which increases linearly with increasing grain size. Although the number of absorbed quanta required for is essentially independent of particle size, the current concentration of a given number of particles is directly related to their particle size. if,
If the aim is to obtain a maximum concentration of 2, it is necessary to use a much smaller number of particles with an average diameter of 0.4 micrometers compared to, for example, those with an average diameter of 0.2 micrometers. The smaller the amount of radiation required to make the particles visible.

Unfortunately, the concentration induced by the thicker gold particles is enhanced at fewer points,
lnt-4o-paint) concentration fluctuations are larger. The observer's perception of density variations between two points is called "graininess." An objective measurement of concentration variation between two points is called "granularity".Although quantitative measurements of granularity have been made in various forms, granularity is most commonly measured as RMS (root mean square) granularity. It is measured as. RMS granularity is defined as the standard deviation of the concentration within the observed microaperture (eg, 24-48 micrometers). Once the maximum allowable granularity (also commonly referred to as grain, but not to be confused with silver halide grain) for a particular emulsion layer is determined, the maximum sensitivity that can be achieved for that emulsion is also effectively limited. Ru.

True improvement in silver halide emulsion sensitivity can be achieved by increasing sensitivity by increasing granularity, decreasing granularity without reducing sensitivity, or by improving both sensitivity and granularity simultaneously. be. Such improvements in bottle sensitivity are generally and simply referred to as improvements in the sensitivity-granularity relationship of emulsions in the photographic field.

The graph shown in Figure 1 shows that five silver halide emulsions 1.2°3.4 and 5, which have the same composition but different grain sizes, were subjected to the same sensitization treatment, and the same coating film was obtained. Furthermore, the sensitivity-granularity relationship for nine emulsions subjected to the same processing was determined by the sensitivity-grainness relationship, although individual emulsions differ in maximum sensitivity and granularity, as shown by A predictable linear relationship exists between the emulsions. All emulsions along the 1I frame exhibit the same speed-granularity relationship; emulsions that show true improvement in speed lie above the speed-granularity line6, e.g. Emulsions 6 and 7 present on wIB are superior to any of emulsions 1 to 5 in the sensitivity-granularity relationship. Emulsion 6 has a higher sensitivity than Emulsion 1, but the granularity is not as high. Emulsion 6 has the same sensitivity as Emulsion 2, but the granularity is much lower. Emulsion 7 has a higher sensitivity than Emulsion 2. However, the granularity is lower than that of emulsion 3, the sensitivity of emulsion 3 is lower than that of emulsion 7, and emulsion 8, which is located below the sensitivity-granularity line, has the lowest sensitivity-granularity in Figure 1. showing the relationship,
Emulsion 8 exhibits the highest photographic sensitivity among the above emulsions, but
Its sensitivity only increases non-proportionally with granularity.

Because of the importance of the sensitivity-granularity relationship in the field of photography, great efforts have been made to quantify and generalize sensitivity-granularity measurements. It is usually a simple table to accurately compare the sensitivity-granularity relationships of a series of emulsions differing in -characteristics. The sensitivity-granularity relationships of photographic products that exhibit similar time-sensitivity curves are often compared. However, no quantitative sensitivity-granularity comparison technique has been established that represents a constant representation of photographic elements, since sensitivity-granularity comparisons become dramatically more complicated when other photographic properties are included. This is because it is necessary. Furthermore, the sensitivity-granularity relationship of photographic elements that form silver images (e.g., black-and-white photographic elements) and the photographic elements that form dye layers (e.g., black and white photographic elements) are discussed.
There are many factors to consider in addition to silver halide grain sensitivity when comparing the speed-granularity relationships of (eg, color and chromogenic photographic elements). This is because the nature and nature of the materials that produce the density and therefore account for the granularity are very different. For more information on granularity measurements in silver and dye image formation, see Understanding Grainness and Granularity (Und@rstandingGralnin@s
s and granularlty) J% Kodak Publication AF-20, Rev. 1l-79 (East 1 Kodak Company, Rotinister, 2, - York 14650
Published by Zwiak, Quantitative Study of Factors Affecting Gradability (Quantitati Ma・8t);
soll*s of Factors Aff@cti
ng Granularty) Js Photographic Science and Engineering, Volume 9, 43. May-June% 1965: Ericsson (Eri.
son) and Marchant (Mar-hant)
, "Loss of Monodisperse Photographic Emulsions 8 Grainness", Photographic Science and Engineering Vol. 416,
A4. July-August, 1972, pp, 253-257:
and Trabka, “Random Sphere Model for Dye Purchase,” Photography, Re-Science,
And, Engineering, Volume 21, Mu 4. July - 8
See May, 1977.119.183-192.

Silver bromoiodide emulsions with outstanding silver imaging (black and white) speed-granularity characteristics are described in U.S. Pat. No. 3,320,069. This specification discloses gelatin-silver bromoiodide emulsions in which silver iodide preferably accounts for 1 to 10 moles of halide.

The emulsions are sensitized with sulfur, selenium or tellurium sensitizers.

This emulsion has a silver coated lid on the support of 0,
It was coated at 300-1,0001% J per 929 m), exposed using an intensity-scale sensitive needle, and exposed at 20° C. (681 F.) using Da-re developer DK-50 (N When processed for 5 minutes using -Methyl-Rua-denophenolsulf It is. Preferably, gold is used in combination with a sulfur-based sensitizer; thiocyanate may also be present during silver I.rhodanide precipitation, and if desired, thiocyanate may be present at any time prior to washing. may be added to the silver halide, the use of thiocyanates during silver halide precipitation formation and sensitization are described in U.S. Pat. No. 2,221,805, U.S. Pat.
No. 2,642,361. The emulsions described in US Pat. No. 3,320,069 also exhibit remarkable speed-granularity characteristics in color photography (although no quantitative values for dye image granularity are given).

U.S. Patent No. 3,656,962, U.S. Patent No. 3.852,0
No. 66 and No. 3,852,067 teach the incorporation of inorganic crystalline materials into silver halide emulsions. According to these documents, the light sensitivity of a silver halide emulsion can be changed by physically and closely bonding silver halide grains and inorganic crystals. U.S. Pat. No. 3,140,179 discloses that the lower part of an optically sensitized emulsion is primarily made of silver chloride.
) and further increase the sensitivity and contrast of the optically sensitized emulsion by coating four emulsions with sufficiently low sensitivity such that no visible image is formed within the optically sensitized emulsion during exposure and development. It teaches that it is possible to improve. U.S. Pat. No. 3,152.907 teaches that similar advantages can be obtained by blending a less sensitive silver chloride emulsion with an optically sensitized silver chloride or silver bromoiodide emulsion. are doing.

British Patent Application No. 2,038,792A (100)
It is taught to selectively sensitize cubic grains that are surrounded by and therefore bounded by crystal faces at the corners of the cube. Such sensitization is
This can be achieved by first forming tetradecahedral silver bromide grains. These particles are ordinary cubic particles surrounded by (100) main crystal planes, but if there is a defect in a corner of one cube, in each case, the missing corner is placed adjacent to the (111) ) Remaining crystal planes. Silver chloride was then added to these (111)
selectively deposited on crystal faces. The resulting grains can be selectively chemically sensitized at some of the silver halide corners. Sensitivity can be improved through localization of such sensitization. Regarding complex crystals, they respond to sensitization if they are silver chloride, and to development, fixing, and cleaning during photographic processing if they are silver bromide. In response to, it is disclosed.

In the table of British Patent Application No. 2.038,792A, (
111) Suzuki and Ueda, ``Chemical Sensitization of Monodisperse AgBr Emulsions'' have not been taught or proposed how selective site sensitization can be applied to grains having only crystal faces. Active site for (Th@A
ctima・8mouth・s forChemiaal 8@n
5itlzation of Monodlsp@rm
@AgBrEmu1mlons) J a 1973
, 5PSK Tokyo Syniumium is also believed to have made similar disclosures. However, in this case, the silver bromide cube;
Ostwald ripening of ultrafine silver chloride particles is carried out on the chi.

During chemical sensitization, sensitized sites of silver nitride emulsions are usually formed on the grain surfaces, and the distribution of these sites is more or less random. Even in cases where a particular arrangement on the particle appears to be slightly advantageous, for example, in cases where the sensitizing sites are more concentrated near the edge of the particle. , those sensitizing sites will still exist randomly\discretely from each other. In order to form latent image sites on the silver halide grains, a large number of photoelectrons (photog*n@rat@d
Clearly, closely adjacent sensitizing sites can compete for photoelectrons in the area of the silver halide grain in which they reside, since it is necessary to capture Therefore, in the absence of such competition, it is not possible to increase the sensitivity of silver halide grains to the maximum level that could otherwise be achieved.

Margin (3) Disclosure of the Invention An object of the present invention is to provide a tabular grain halide complex emulsion comprising a dispersion medium and silver halide grains and having enhanced sensitivity. consists of a dispersion medium and silver halide grains as described above, and at least 50% of the total projected area of the silver halide grains
However, the thickness is less than 0.5 micrometer and the diameter is at least 0.
．． 6 micrometers and an average aspect ratio of 8:
occupied by tabular silver halide grains larger than 1; parallel parallel (111) principal crystal planes surrounding and bounding the tabular silver halide grains; and This can be achieved by a tabular grain 7% C1R silver emulsion characterized in that a silver salt is disposed on selected surface sites of the tabular grains. Tabular grain emulsions and their preparation The tabular grains of the present invention are surrounded by counter-rotating parallel or nearly parallel (111) major crystal planes, and these grains generally have a hexagonal or triangular shape. The opposing main crystal planes of the tabular silver halide grains according to the present invention are parallel. The term "parallel," as it is used herein, is intended to encompass surfaces of the numerals that appear parallel under direct or indirect visual inspection at 10,000x. The term "high aspect ratio" as it is applied to the silver aspect ratio of the present invention has a grain size of less than 0.5 micrometers and a minimum of 0.5 micrometers.
With the requirement that the silver halide grains having a diameter of 6 micrometers have an average aspect ratio greater than 8:1 and occupy at least 51 mm of the total projected area of the silver halide grains, ζ can be defined here.

Preferred high aspect ratio tabular grain nolognized silver emulsions of the present invention are less than 0.3 micrometers (
The emulsion is such that the silver halide grains have an average aspect ratio of at least 12:1, preferably at least 20:1. - These silver halide grains meeting the above-mentioned thickness and diameter criteria occupy, in a preferred form of the invention, at least 7 o*s and preferably at least 90 in of the total projected area of the silver halide grains.

It is understood that the thinner the thickness of the tabular grains that account for a given percentage of the projected area, the higher the average aspect ratio of the emulsion. Typically, the tabular grains have an average thickness of at least 0.03 micrometers, preferably at least 0.03 micrometers.
0.05 micrometers (for example, 0.0 micrometers)
Although tabular grains thinner than 1 micrometer can also be used in principle). An example is Il! which recognizes that the thickness of tabular grains can be increased to satisfy specific applications. For ll image transfer film units, tabular grains having an average thickness of up to 0.5 micrometers are useful. Average particle thicknesses of up to 0.5 micrometers will also be discussed below in the blue light recording section. However, in order to achieve a high aspect ratio without excessively increasing the 11 diameter of the particles, The tabular grains of the emulsion will have an average thickness of less than 0.3 micrometers. The thickness of the tabular grains as reported here is based on the thickness of the host grain and, as detailed below, increases in thickness attributable to epitaxial deposition of silver salts. does not include.

The above-mentioned grain characteristics of the silver halide emulsions according to the invention can be easily ascertained by techniques well known to those skilled in the art. The term "aspect ratio" as used herein refers to the ratio of diameter to thickness of a particle. What is the “diameter” of a particle?
Microscope (t or electron microscope) photograph of the emulsion sample
It shall refer to the diameter of a circle having an area equal to the projected area of the grain when 0° less than 5 micrometers (
Tabular grains having a diameter of at least 0.6 micrometers) and a diameter of at least 0.6 micrometers can be identified. From the diameter and thickness thus measured, the aspect ratio of each such tabular grain can be calculated, and has a thickness of less than 0.5 micrometers (0.3 micrometers) and a diameter of at least 0.5 micrometers. The aspect ratios of all particles in a sample that satisfy the 6 micrometer criterion can be averaged to obtain their average aspect ratio. As is clear from this, the average aspect ratio is the average aspect ratio of individual tabular grains. It is convenient to determine the average thickness and average [diameter] of tabular grains with a diameter of less than 0.6 micrometres and a diameter of at least 0.6 micrometers and calculate the ratio of these two average values to determine the average aspect ratio. Using the average image of the individual aspect ratios to determine the ratio, as well as the average values of thickness and diameter, within the tolerances of possible particle measurements, yields There is virtually no difference in the average aspect ratio of the silver halide grains that satisfy the thickness and diameter criteria, and the projected area of the remaining silver halide grains in the photomicrograph is also summed separately. ,and,
From these two total values, the percentage of the total projected area of the silver halide grains occupied by tabular grains satisfying the thickness and diameter criteria can be calculated.

In the above-mentioned regulations, standard tabular grain thicknesses of less than 0.5 micrometers (preferably less than 0.3 micrometers) are compared to the very thin tabular grains possible in the present invention to thicker tabular grains with inferior photographic properties. In order to distinguish from
Selected. 0.6 micrometers was chosen as the standard particle diameter. This is because it is not always possible to distinguish between tabular and non-tabular grains in micrographs when the diameter is very small.The term "projected area" is widely used in the industry. The term “projection area (
glozexi, n eria or projectites
・This term is used in the same way as ``Aeria''. This term is used in the same meaning as ``Jam@s'' and Higgins, ``The Fundamentals of Photographic Theory''.
@ntals of PhotographyTh@
ory) J Morgan & Morgan, 2.

- See York, p. 15.

High 7 spectral ratio tabular grain silver bromoiodide emulsions are prepared by precipitation methods as described below. It can be done: The dispersion medium is placed in a conventional silver oxide precipitation reaction vessel equipped with a V-effective stirring mechanism. Typically, the amount of dispersion medium introduced into the reaction vessel in the initial stage is at least about 10% by weight of the dispersion medium present in the silver bromoiodide emulsion in the final stage of grain precipitation, preferably from 20 to 80% by weight. Yes (based on the total weight of the dispersion medium). As taught in Persee Patent No. 866,645 (corresponding to French Patent No. 2,471,620), the dispersion medium can be removed from the reaction vessel by ultrafiltration during the silver bromoiodide grain precipitation process. Therefore, the volume of dispersion medium initially present in the reaction vessel can be equal to or even higher than the amount of silver bromoiodide emulsion present in the reaction vessel during the final grain precipitation stage. The initially introduced dispersion medium is preferably water or an aqueous dispersion of a deflocculant, and this dispersion medium may optionally contain other components,
Examples include one or more silver halide ripening agents and/or metal douging agents as detailed below.If the peptizer is present initially, it is present at the final stage of silver bromoiodide precipitation. It is preferred to use it in a concentration of at least 10% of the total amount of deflocculant, particularly preferably at least 20%. Additional dispersion medium is added to the reaction vessel along with the silver and halide salts, which can also be introduced from a separate jet.In general, the addition of halide salts, especially to increase the peptizer proportion, is Adjust the proportion of dispersion medium after completing the introduction.

A small proportion of bromide salt used to form silver bromoiodide grains, usually 1
Less than 0% by weight is initially present in the reaction vessel to control the bromide ion concentration in the dispersion medium at the beginning of silver bromoiodide precipitation. Also, the dispersion medium in the reaction vessel is initially free of iodide ions, since the presence of iodide ions before the simultaneous addition of silver and bromide salts will result in the formation of thick, non-tabular grains. The term ``substantially free of iodide ions'' as used in relation to reaction vessel circulars refers to the fact that iodide ions precipitate as a separate silver iodide phase compared to bromide ions. This means that the iodide concentration in the reaction vessel before introducing the silver salt is less than 0.5 mole of the total concentration of halide ions present. It is desirable to maintain the If the pHlr of the dispersion medium is initially too high, the tabular silver bromoiodide grains produced will be relatively thick and therefore have a low aspect ratio. The pBr in the reaction vessel can be initially maintained at or below 1.6, preferably below 1.5. On the other hand, if the pBr is too low, non-tabular silver bromoiodide grains are likely to be formed. Therefore, the pBr of the reaction vessel can be maintained at 0.6 or more, preferably 1.1 or more. pBr is defined as the negative logarithm of the bromide ion concentration. - and pAg 4s
Further, hydrogen and silver ion concentrations are similarly defined.

During precipitation, silver, bromide and iodide salts are added to the reaction vessel according to techniques well known for the precipitation of silver bromoiodide grains. Typically, at the same time as the introduction of the bromide and iodide salts, for example silver nitrate, etc. An aqueous solution of soluble silver salt is introduced into the reaction vessel. In addition, bromide and iodide salts are usually one or more types of ammonium, alkali metal (
For example, it is introduced as an aqueous salt solution, such as an aqueous solution of a halide salt of an alkaline earth metal (eg, sodium or potassium) or an alkaline earth metal (eg, magnesium or calcium). The silver salt is introduced into the reaction vessel separately from the iodide salt, at least initially. The iodide and bromide salts may be added to the reaction vessel separately or as a mixture.

Introducing the silver salt into the reaction vessel initiates the nucleation stage of particle formation. As the introduction of silver, bromide, and iodide salts continues, a population of grain nuclei is formed that serves as sites for precipitation of silver bromide and silver iodide.

The precipitation of silver bromide and silver iodide onto the grain nuclei present constitutes the growth stage of grain formation. The aspect ratio of the tabular grains formed according to the present invention is The growth stage is less affected by the chloroiodide and bromide concentrations.Therefore, the permissible range of par in the stage where silver, bromide and iodide salts are simultaneously introduced is reduced to 0 during the growth stage.
．． 6 or more, preferably in the range of about 0.6 to 2.2, more preferably in the range of about 0.8 to about 1.6. Of course, it is possible and advantageous to keep the pBr in the reaction vessel during the introduction of the silver and halide salts within the initial limits mentioned above before the introduction of the silver salts. This makes silver highly polydisperse when preparing emulsions.

It is particularly advantageous if particle nucleation continues at a rate substantially equal to the bromide and iodide salts. pB
Increasing the r value to 2.2 or more in the tabular grain growth stage increases the thickness of the resulting grains, but still yields grains with an average aspect ratio greater than 8=1.
acceptable in many cases.

Instead of introducing the silver, bromide and iodide salts as aqueous solutions, the silver, bromide and iodide salts are introduced at an early or growing stage in the form of fine iron halide particles suspended in a dispersion medium. Can be done.

The particle size is such that when the particles are introduced into the reaction vessel, Ostwald ripening will readily occur onto larger particle nuclei, if present. The maximum useful particle size depends on the specific conditions within the reaction vessel,
It will depend, for example, on the temperature and the presence of hIMing and ripening agents. Silver bromide.

Silver iodide and/or silver bromoiodide grains can be introduced. Silver chlorobromide and silver chlorobromoiodide grains can also be used since bromide and/or iodide precipitate in preference to chloride. The silver halide grains are preferably very fine, e.g. with an average diameter of less than 0.1 micrometer. Provided that the above pBrQ requirements are met, silver, bromide and iodide salts are preferred. The concentration and rate of introduction may be any conventionally advantageous. Although it is preferable to introduce the silver and halide salts at a concentration of 90.1 to 5 moles per liter, a wider concentration range than conventionally used, for example from pO001 to saturation, can be used. Adoptable. A preferred method of precipitation is one that seeks to reduce precipitation time by increasing the rate of silver and halide salt introduction during the run. The rate of introduction of silver and halide salts can be determined by increasing the rate of introduction of the dispersion medium and silver and halide salts, or by increasing the concentration of silver and halide salts in the dispersion line being introduced.
It can be increased. Although it is advantageous to increase the rate of introduction of silver and halide salts, U.S. Pat. Publication No. 2,107,118, W-Lonota%ken Application No. 801
No. 02242, and the growth mechanism of AgBrWi crystals in gelatin solution.
M@chanism of AgBrCrystals
in Ge1atln 5olut1on) J Ph
otographic8cients @ and E
ngin earing + Vol-21*A
Keeping the rate of introduction below a threshold at which generation of severe particle nuclei is likely to occur (i.e. to avoid re-nucleation) as taught in January-February 1977, p. 14 et seq.
This is advantageous for 41. Emulsions having coefficients of variation of less than about 30 can be prepared.

(The coefficient of variation used herein means 100 times the standard deviation of particle diameter divided by the average particle diameter.) By intentionally performing re-nucleation during the growth stage of the precipitate, Of course, polydisperse emulsions with substantially higher coefficients of variation can be prepared. The iodide concentration in the silver bromoiodide emulsions according to the invention can be controlled by the introduction of iodide salts. Any commonly used iodide concentration can be employed. Even very small amounts of iodide, as low as 0.05 mole, are recognized as useful in this art. In their preferred form II, the emulsions of the invention have:
Containing at least about 0.1 mole of iodide, silver iodide up to the limit of soluble Ps in silver bromide at the grain formation temperature can be incorporated into the tabular silver bromoiodide grains. Silver iodide can be present in tabular silver bromoiodide grains at concentrations of up to about 407 Roux at temperatures of 90°C. At the end of the day, the precipitation temperature is set to about room temperature, for example about 30"
It can be lowered by c-i. Generally, it is desirable to carry out the precipitation at a temperature range of 40-80°C. For most photographic applications, it is desirable to limit the maximum iodide concentration to about 20 molar. The best iodide concentration is up to about 15 mol S.

A substantially uniform iodide profile (distribution) in the tabular silver bromoiodide grains by maintaining a constant relative proportion of iodide and bromide salts introduced into the reaction vessel during the precipitation process.
It is also possible to create various photographic effects that vary the above relative proportions. Increasing the proportion of iodide in the annular regions of high aspect ratio tabular grain silver bromoiodide emulsions compared to the central regions of the tabular grains provides certain photographic property advantages. The iodide concentration in the central region of the tabular grains is θ~5
The iodide concentration in the laterally encircling annular region can vary in the molar range from at least 1 molar higher to the solubility limit of silver iodide in silver bromide, preferably about 20 molar. Up to arrogance, optimally about 15
The tabular silver bromoiodide grains of the present invention can have a substantially uniform or gradually varying iodide concentration profile; The concentration gradient can be controlled as desired to increase the iodide concentration within the tabular silver bromoiodide grains or to increase the iodide concentration at or near the outer surface of those grains.

Although one method for preparing high aspect ratio tabular grain silver bromoiodide emulsions has been described with reference to the above method of representing neutral or non-ammoniac emulsions, emulsions according to the invention and their utility are specific. It is not limited by the method of preparation. According to another method, silver halide spear particles are first present in the reaction vessel. The silver iodide chain degree in the reaction vessel was reduced to less than 1 mol, and the maximum size of silver iodide grains initially present in the reaction vessel was reduced to less than 0.05 micrometers. reduced.

Iodide-free high aspect ratio tabular grain silver bromide emulsions can be prepared by the process detailed above with iodide-free modifications. High aspect ratio tabular grain silver bromide emulsions can also be prepared by the method based on Funatsuk and Shadow, cited above. Still other methods of preparing iodide-free high aspect ratio tabular grain silver bromide emulsions are described in the Examples below.

Further enhancing the versatility of high aspect ratio tabular grain silver halide emulsions that can be used in the practice of this invention, tabular silver chloride grains substantially free of both silver bromide and silver iodide are used. ! Description of the method - In this preparation, a double jet precipitation method is used in which both chloride and silver salt are introduced simultaneously in the presence of ammonia into a reaction vessel containing a dispersion medium.

PAg tube 6.5-10 in dispersion medium during introduction of chloride salt
and maintain the voice in the range of 8 to 10 - with the presence of ammonia at higher temperatures,
Tends to produce thick particles.

Therefore, a high aspect ratio tabular grain silver chloride emulsion vI4
I! ! In this case, the precipitate formation temperature is limited to 60°C.

(111) has opposing crystal planes in the crystal plane and, in one preferred form, is in one interior of the main view surface (2
11) It is also possible to prepare tabular grains containing at least 50 mol-0 chloride having at least one edge parallel to the crystal vector. Such tabular grain emulsions are prepared by reacting an aqueous silver salt solution with an aqueous solution of a chloride-containing halide group in the presence of a habit-altering amount of an aminoazoindene and a thioether bond-containing peptizer.
It can be prepared.

Tabular grain emulsions consisting of silver halide grains containing chloride and bromide throughout at least the annular region of the grain and preferably throughout the grain can also be prepared. The tabular grain regions containing silver chloride and silver bromide are exposed to moles of chloride and bromide ions during the introduction of silver, chloride, bromide, and optionally iodide groups into the reaction vessel. Maintaining the ratio in the range of 1.6:1 to about 260:1 and controlling the total concentration of halide ions in the reaction vessel from 0.10 to
0.90 Formed by maintaining within the specified range.
The molar ratio of chloride to bromide in tabular grains is 1
:99 to 2:3.

High aspect ratio tabular grain emulsions useful in the practice of this invention can have very high average aspect ratios. The average aspect ratio of tabular grains can be increased by increasing the average grain diameter (grain size). In this way advantages regarding sharpness can be obtained. However, the maximum average particle diameter is generally limited by the granularity requirements imposed for a particular photographic application.

The average aspect ratio of the tabular grains can be increased, additionally or selectively, by lowering the average grain thickness. Granularity can be improved by decreasing the aspect ratio.Such granularity improvement can be achieved as a direct function of increasing aspect ratio.Thus, the maximum average aspect ratio of tabular grain emulsions according to the invention The ratio is a function of the maximum average grain diameter acceptable for a particular photographic application and the minimum tabular grain thickness achievable that can be manufactured. It has been found that the maximum average aspect ratio varies depending on the precipitation method used and the tabular grain halide composition.For tabular grains with photographically useful average grain diameters, I! Ostwald ripening of silver bromide grains resulted in the highest average aspect ratio of 500:1 observed.
The I4 manufacturing method can achieve 9.100:
Even higher aspect ratios of 1.200:1 were achievable by double jet precipitation. The presence of iodide usually reduces the maximum average aspect ratio that can be achieved; however, the average aspect ratio is 100:1 or 200:1.
It is also possible to prepare silver bromoiodide tabular grain emulsions that are even larger.

For silver chloride tabular grains optionally containing bromide and/or iodide, average aspect ratios as large as 50:1 or even K100:1 can be achieved. Modifying compounds can be present during the precipitation of the tabular grains. Such a compound may be initially present in the reaction vessel or may be prepared in accordance with conventional methods.
It can also be added along with salts of the same class or higher. U.S. Patent No. 1.195.432, U.S. Patent No. 1,9
No. 51.933, Pl. No. 2.448,060, No. 2
, No. 628,167, No. 2.950,972, No. 3.488,709, No. 3.737,313, No. 3. t 72. Oa No. 1 and Oa No. 4.269,92
No. 7, and R・5earch 015g1osure
Vo1.134. June 1975, Item 134
52, such as copper, thallium, lead, bismuth, cadmium, zinc, intermediate chalcones (i.e., sulfur, selenium, and tellurium), gold, and compounds of Group 1 precious metals, as described in Modifying compounds can be present in excess of silver halide precipitation.

R@s@arch Diselosur and its predecessor (old version) Predmat Li*enslng
Induat
Rral Opportunitl*aLtd.
) etc.a Journal of Photography
As described in icSc1@ne** Vol, 25 e 1977, PP, 19-2', reduction sensitization can be performed internally during the precipitation formation process.

The respective silver salts and silver salts are described in U.S. Pat.
, No. 821,002 and No. 3,031,304, and Craze (C1a@s) et al., Ph@tograph
lsehsKorr @5pond ・as a
1land 1 02 s Numb @r
1 0 6 1967, P, 162, the feed rate was adjusted and the reaction vessel contents -@
pBr and/or pAg can be added to the reaction vessel using a feeding device or using a gravimetric feed through the supply tube under the nine or two sides to keep the pBr and/or pAg adjusted. For rapid distribution of reaction components, U.S. Pat.
No. 42,605, No. 3.415.650, No. 3.
785,777, 4,147,551 and 4,171,224, British Patent Application No. 2,022,4
No. 31A, German Patent Application No. 2,555,36
No. 4 and No. 2,556,885 and l@s@ar
chDlselosure, Vol, 166 m 1
A specially constructed mixing device as described in February 978 e It@m16662 can be used.

In preparing tabular grain emulsions, a dispersion medium is initially placed in a reaction vessel. In a preferred form, the dispersion medium comprises an aqueous dispersion of peptizer, which may employ a peptizer concentration of from 0.2 to about 10% by weight, based on the total weight of the emulsion components in the reaction vessel. The deflocculant concentration in the reaction vessel is maintained at less than about 60% by total weight before and during the formation of the no-logonization process, and supplemental additives are added afterwards to ensure optimum coating properties. It is a common practice to adjust the emulsion vehicle concentration to a high concentration by adding a vehicle to the initially formed emulsion. is about lO~3(
The concentration can be increased to values as high as 1 mole of silver halide afif000 J' by adding additional vehicle from the bale, which can contain 1 molar peptizer. Preferably, the concentration of vehicle in the finished emulsion is greater than about 30 to 70 psoits per mole of silver I.rodanide in the emulsion layer during coating and drying during the manufacture of a photographic element. Preferably, the weight is accounted for by the vehicle.

The vehicle (including both the binder and the peptizer) can be selected from those commonly used in chemical emulsions. Preferred deflocculants are hydrophilic colloids, which can be used alone or in combination with hydrophobic substances. Suitable hydrophilic substances include proteins, protein derivatives,
cellulose derivatives such as cellulose esters,
For example, alkali-treated gelatin (beef bone or skin gelatin)
or gelatin, such as acid-treated gelatin (porgskin gelatin), and materials such as gelatin derivatives, such as acetylated gelatin and phthalated gelatin. These and other vehicles are R@s@are
h Disclost+r*, Vol, 176 *l
December 978 #Item 1 7643
a S@*tlon ■Described in ■. Hydrophobic materials are particularly useful when used with vehicle materials containing hydrophilic colloids, as well as in overcoat layers, as well as in the emulsion layers of photographic elements according to the invention.

They can be incorporated into other layers such as interlayers and layers located below emulsion layers.

Grain ripening may occur during the production process of silver heronide emulsion Ov4 according to the present invention. It is desirable that grain ripening occur in a reaction vessel at least during the production process of silver bromoiodide grains. Known silver halide solvents are useful for promoting rounding, for example, the presence of excess bromide ions in the reaction vessel to promote ripening. It is therefore clear that ripening can be accelerated simply by pouring a bromide salt solution into the reaction vessel. Other ripening agents can also be used, or the entire amount of these ripening agents can be blended into the dispersion medium in the reaction vessel before adding the silver and silver compound salts. , one or more types of I.rodanide salt a@salt or w4w
It can also be introduced into the reaction vessel together with the s-agent. As a further variant, the ripening agent can also be introduced independently at the stage of adding the halide salt and silver salt. Although ammonia is a known ripening agent, it is not preferred as a ripening agent for use in the ♦ emulsions of the present invention which exhibit the highest attainable speed-granularity relationship.

Some preferred ripening agents include sulfur. Thiocyanate salts, e.g. alkali metal thiocyanate salts,
In particular, sodium and potassium thiocyanate salts and ammonium thiocyanate salts can be used.

Although the amount of thiocyanate salt introduced may be any conventionally used amount, the preferred degree of thiocyanate salt is generally in the range of about 0.1 to 20 J' per mole of silver rhodanide. The use of thiocyanate ripening agents is described in U.S. Pat. No. 2,222,264;
Same No. 2.448.53445 and Same No. 3,320,06
The conventional convergence teaching can be found in No. 9. Otherwise,
For example, US patent @3,271,157-it-1i'J
Conventional thioether ripening agents such as those disclosed in No. 3,574,628 and No. 3,737,313 can also be used.

The high aspect ratio tabular grain emulsions of this invention are preferably washed to remove soluble salts. Removal of soluble salts is described in Research Discloatre, Vol.
-176, December 1978, I tow 1764
3. Decant and filter as described in S@etion■.

and/or by well-known techniques such as cryo-sedimentation and leaching. Prior to use, the emulsions with or without sensitizers are dried and stored. In the present invention, the emulsions with or without sensitizers are dried and stored. It is particularly advantageous to carry out the washing at the end of the ripening of the tabular grains, after the wrinkle formation is completed, in order to avoid an excessive increase in the .

According to the method for preparing tabular silver halide grains described above, a high aspect ratio tabular grain emulsion is prepared in which the tabular grains account for at least 50 - of the total projected area of the entire silver halide grain population. However, it is recognized that greater benefits are achieved by increasing the proportion of such tabular grains present. Preferably, the tabular silver halide grains account for at least 70% (preferably at least 90 inches) of the total projected area. Although the presence of small amounts of non-tabular grains is completely acceptable in many photographic applications, the proportion of tabular grains can be increased to obtain all the benefits of tabular grains. Larger tabular silver halide grains can be separated from smaller non-tabular grains in a mixed grain population using conventional separation techniques such as centrifugation or hydrocycling. Hydrocycle separation is taught in US Pat. No. 3,326,641.

E. If the tabular grain has sensitized sites that satisfy the thickness and diameter criteria set forth above for controlled local epitaxy and determination of sensitized aspect ratio, and these sites were selected for the grain. The orientation is one unique feature of the present invention.

In one preferred form, the tabular grains have at least one silver salt deposited on the grains by epitaxial growth, i.e. the silver salt is in the form of oriented crystals. , and therefore its orientation is similar to that of the crystal substrate (
It is controlled by tabular silver halide grains on which silver salts grow. Furthermore, the epitaxy of the silver salt is substantially limited to selected blush sites (localized areas). It can be substantially limited to the central region of the main crystal planes, the blocky regions of the respective main crystal planes, and/or the peripheral regions at the edges of the main crystal planes.

In yet another preferred form, epitaxy of the silver salt can be substantially confined to regions located at or near the corners of the tabular grains. Combinations of regions as described above are also possible. For example, epitaxy confined to the central region of the tabular grains can be combined with epitaxy at the corners of the tabular grains or warped to the edges of the grains to effect growth. The common features of each of these aspects are:
Controlling silver salt epitaxy by confining it to selected sites, thus substantially eliminating silver salt epitaxy from at least a portion of the (111) major crystal faces of tabular silver rhodanide grains. This is a very unexpected result, but if the deposition by epitaxial growth is limited to selected regions on the tabular grains, it is possible to "Surface Structure and Epitaxial Growth", Journal Otsu Agelide Physics, Vol. 35, 4.
7. As described in July 1964, pp. 2165-2169, an improvement in sensitivity was achieved compared to the case where silver salt was epitaxially grown randomly over the entire growth surface of tabular grains. It has been found that it can be obtained.

The epitaxy of the silver salt is limited to a selected sensitized region so that at least a portion of the main crystal plane substantially contains the silver salt deposited by epitaxial growth, but the extent to which the epitaxy is limited in this case is may be varied over a wide range without departing from the scope of the present invention.

Generally, as the amount of epitaxial growth on one principal crystal plane decreases, a greater increase in sensitivity is realized. The epitaxially deposited silver salt is less than one-half the area of the major crystal faces of the tabular grains, preferably less than 25 inches, and certain forms of deposition, such as deposition of the silver salt by epitaxial growth at the corners, are preferred. In this case, it is particularly preferably possible to limit the area to less than 10% of the area of the main crystal faces of the tabular grains, or even to less than 5 inches. In some embodiments, it has been shown that TSTXO deposition during epitaxial growth begins on the edge surfaces of tabular grains; therefore, in locations where epitaxy is limited, one option is to This confines epitaxy to the 92-edge I& site, and effectively eliminates epitaxy on the main crystal planes.

Silver salts deposited (by epitaxial growth) can be used to create sensitizing sites on the tabular iron halide host grains.

Through controlling the sites of epitaxial deposition, it is possible to achieve selective local sensitization of tabular host grains. By "regular" is meant that the sensitizing sites possess a predictable and ordered relationship to the major crystal faces of the tabular grains, and preferably to each other. By controlling the deposition of epitaxial silver salts with respect to the major crystal planes of the tabular grains, it is possible to control both the number and lateral spacing of the sensitizing sites.

In some cases, selective local sensitization can be seen when exposing silver halide grains to radiation to which they are sensitive, and sensitizing the intracapsular latent image center. It can be formed at the site. In cases where particles carrying latent image centers are to be developed entirely, the location and number of those latent image centers cannot be determined. However, if we stop the development before it spreads from the bottle to the immediate vicinity of the center of the latent image, and then we magnify the particles that have undergone partial expression, then You can clearly see the parts. These partially developed areas typically correspond to areas at the center of the latent image, and these areas at the center of the latent image generally correspond to sensitized areas. This is a microscopic photograph showing tabular grains after partial development. From this photograph, the things explained earlier can be seen. The black spots in this photomicrograph are developed silver. It should be noted that although the silver extends laterally across the grain in an irregular manner, the contact points between the silver and the tabular grains are regular. It is. That is, a predetermined relationship exists between the contact point and the corner of the particle. Because of this relationship, it is possible to effectively secure the space between contact points, and it is also possible to limit the number of contact points for each particle.

To contrast the regular tabular relationship of sensitization sites illustrated in FIG. 2, please refer to FIG. 3, which depicts a high 7 spectral tabular grain emulsion that has not been sensitized in accordance with the present invention. Note that the black spots indicating silver development are more or less randomly distributed within the grain.

It is often seen that the contact points between the developed silver and the grain edges are very close together. In the case of FIG. 3, it cannot be found that there is a regular relationship between the sensitized sites and the main crystal planes of the particles.

Although in the case of certain preferred emulsions, such as those shown in FIG. It is impossible to do so. For example, if the formation site of the latent image is located inside the particle, rather than within or near the particle, it is difficult to establish the latent image site through partial particle development. This is because dissolution of the particles occurs simultaneously with development.In other cases, the sensitized sites, although themselves regular with respect to the particle geometry,
・For example, when regular sensitizing sites act as hole traps, these sites become photopressure holes (positive holes generated by light). The photopressure hole is captured by capturing the hole (hole) and preventing the annihilation of electrons (photoelectrons) generated by light.

Therefore, sensitization according to the present invention at discrete regular sites is independent of whether the latent image is formed at regular or random sites on the particle. In many cases, the selective local sensitization of the present invention at discrete regular sites can be confirmed by electron micrographs and is not as good as performing partial grain development. For example, referring again to FIG. 2, it is clearly visible in the corners of the tabular grains that the epitaxially deposited silver 9-10nide is used to provide selective local sensitization. can. In the case of the emulsion of FIG. 2, the discontinuous regular silver salt epitaxy located at the corners of the tabular grains acts in accordance with the present invention in the direction of selective local sensitization. In cases where deposition by epitaxial growth is limited, selective partial sensitization cannot be detected directly by looking at electron kX micrographs of particle samples. In such cases, a certain amount of knowledge about emulsion precipitation is required.

In a preferred embodiment of the present invention, high aspect ratio tabular grain silver bromoiodide emulsions prepared as previously disclosed herein are chemically sensitized at regular grain sites. . Tabular silver bromoiodide grains have (111) main crystal faces. First, the aggregated spectral sensitizing dye is adsorbed onto the surface of the tabular grains by conventional spectral sensitization techniques.

The adsorption coverage of a single molecule is the minimum of 151. A sufficient amount of dye is preferably used to provide a minimum border. Although it is possible to successfully calculate the dye concentration from the monomolecular coverage, it is clear that the dye itself is not uniformly distributed on the particle surface. If necessary, a larger amount of dye can be introduced than can be adsorbed onto the particle surface, but this is not recommended since adding an excessive amount of dye will not achieve a further improvement in gloss. Although not advantageous, it is possible. The agglomerating dye is used at this sensitization step not for its spectral sensitization properties but for its ability to direct epitaxial growth of silver chloride onto high 7 spectral ratio silver bromoiodide tabular grains.
use. Therefore, any other adsorbable species that can dominate deposition by epitaxial growth and that can be replaced along with the spectral sensitizing dye can be used. The functions of aggregating dyes include both controlling epitaxial growth and providing spectral sensitization, and since it is unnecessary to remove such dyes once they are in place, they do not control epitaxial growth. It is clear that it is a useful substance for.

After the dye to be aggregated has been adsorbed onto the surface of the silver bromoiodide grains, silver chloride can be deposited by conventional precipitation methods or by the Ostwald thermal formation method. This epitaxial growth does not form shells on silver chloride lines or silver bromoiodide grains, nor does it form random deposits. Such silver chloride is rather
It is selectively and regularly deposited adjacent to the corners of the tabular grains. Generally, as the rate of epitaxial deposition decreases, fewer sites are available for such deposition.

Therefore, if desired, epitaxial deposition can be limited to a level less than the entire =-ner. In a variant, peripheral rings can be formed with silver chloride at the edges of the main crystal planes. However, if the amount of silver chloride available for deposition is presently limited, the ring may be incomplete. The epitaxially grown silver chloride by itself serves to significantly increase the sensitivity of the resulting composite grain emulsion without requiring the use of additional chemical sensitization.

In the above-described particularly preferred embodiment of the invention, the tabular grains are comprised of silver bromoiodide grains, and the silver chloride is deposited by epitaxial growth at regular sites on the grains. However, tabular grains and silver salt sensitizers can take a variety of forms. The host tabular grains are
Any conventional silver halide composition known to be useful in the photographic field can be used and capable of forming high aspect ratio tabular grain emulsions. Therefore, silver chlorobromide, silver bromochloride, or silver chloride grains may be included in place of silver bromoiodide in high aspect ratio tabular grain emulsions to be sensitized, and these grains may optionally be May contain small amounts of iodide. Useful proportions of the various halodides are as described above.

A sensitizing silver salt is attached to a selected site on the host tabular grain, and the selection of the silver salt O is usually carried out by
It is possible to carry out epitaxial growth on silver halide grains from among those conventionally known to be useful in the field of photography. The anion contents of the silver salt and the tabular silver grains are sufficiently different that it is therefore possible to discern differences in their respective crystal structures. Surprisingly, even when the tabular grains and corners or diO deposits consist of the same silver halide composition, the presence of adsorbed locally dominant substances (s1t@dir@ctor) In the case of deposit formation on tabular host grains, the growth of non-tabular corners and edges could be observed. Whether the anion contents of the silver salt and the tabular silver halide grains are different or spread out, the inherent (
Modifiers (incorporated) can be present in one or both of them. The silver salt can be selected from those conventionally known to be useful in forming the shell of core-shell opened silver emulsions. Silver salt is
In addition to all known photographically useful silver halides,
Other silver salts known to precipitate on silver halide grains may be included, such as silver thiocyanate, silver phosphate, silver cyanide, silver carbonate, and the like. Such silver salts may be advantageously deposited in the presence of optional modifying compounds such as those described above in connection with tabular silver halide grains, depending on the silver salt chosen and the intended application. can. A portion of the silver halide forming the host tabular grains usually enters the solution during the epitaxial growth deposit formation process and is then mixed into the silver salt epitaxy. For example, silver halide deposits on silver bromide host grains will typically contain a small proportion of bromide ions. Therefore, when we refer to a particular silver salt as epitaxially grown on a host tabular grain, unless otherwise specified, we also refer to silver salts of the same composition in that host tabular grain. We do not intend to exclude the presence of silver halides.

Generally, it is advantageous for the complex salt to exhibit higher solubility than the silver halide of the host tabular grain. In this way, the tendency for tabular grain dissolution to occur during silver salt deposition can be reduced.

In this case, it is therefore possible to limit sensitization to just those conditions that minimize dissolution of the tabular grains, i.e., on tabular grains made of silver halide with greater solubility. The limitations required when depositing silver salts with poor solubility can be avoided. Advantageously, the host tabular grains consist essentially of silver bromoiodide. In the case of silver bromoiodide, it has poor solubility compared to silver bromide, silver chloride or silver thiocyanate and can easily act as a host for the attachment of each of these salts. On the contrary, silver chloride has a higher solubility than silver bromoiodide or silver bromide, so it can be easily epitaxially grown on tabular grains made of any of these halide compositions. can be done, and also
It can be an advantageous silver salt for selective local sensitization. In most cases, silver thiocyanate, which has poor solubility compared to silver chloride but greater solubility than silver bromide or silver bromoiodide, can be used as a substitute for silver chloride. can. However, silver chloride is usually preferred over silver thiocyanate for maximum stability. The epitaxial deposition of less soluble silver salts on more soluble non-tabular silver halide host grains has been reported in the art, and may be used in the practice of the present invention. can be used. For example, silver bromoiodide can be epitaxially deposited on silver bromide, or silver bromide or silver thiocyanate can be deposited on silver chloride. Multilevel epitaxy, ie, silver salt epitaxy on another silver salt, and the silver salt itself being epitaxially deposited on the host tabular grains, is possible. For example, silver chloride can be epitaxially grown on silver bromoiodide or silver bromide host grains, and silver thiocyanate can be further epitaxially grown on this silver chloride.

Controlled localized epitaxy can be achieved over a wide range of epitaxial growth silver salt concentrations. Approximately 0 based on the total amount of silver contained in the composite sensitized particles
．． Increased sensitivity can be achieved when applying silver salt concentrations as low as 0.5 molar. On the other hand, 5
The highest level of sensitivity can be achieved when applying silver salt concentrations of less than 0 molar. Usually, the concentration of silver salt deposited during epitaxial growth is 0.3 to 25 molar.
Advantageously, and for sensitization, it is generally optimal for such concentrations to be about 0.5 to 10 molar.

Adsorbed locally dominant substances, such as agglomerating dyes, can be removed depending on the silver salt to be used and the halide content of the tabular grains exhibiting (111) principal crystal faces; Nevertheless, controlled local epitaxy can be achieved. When the host tabular grains consist essentially of at least 8 moles iodide (preferably at least 12 moles iodide) at their surfaces, the host tabular grains in the absence of adsorbed locally dominant substances Selective epitaxial growth of silver chloride is performed adjacent to the corners of. Surprisingly, tabular silver bromide or silver bromoiodide grains are prepared by incorporating iodide in concentrations as low as 0.1 mol into the tabular silver bromoiodide grains prior to the epitaxial growth of silver chloride. A similar result can be achieved when contacting the aqueous iodizing salt with the aqueous iodizing salt. fabricating tabular silver halide grains of the compositions disclosed herein in the absence of adsorbed locally dominant substances;
Silver thiocyanate can be selectively grown epitaxially at this point.

Although in the case of these combinations of host tabular grains and silver salt sensitizers it is unnecessary to use adsorbed localized substances, it is possible to It is often advantageous to use such locally adsorbed materials to more narrowly limit epitaxial growth.

High aspect ratio, plate-like silver bromoiodide grains with lower concentration in the central region than in laterally surrounding annular or otherwise laterally disposed regions. of iodide can be used. If the laterally surrounding annular region exhibits a surface iodide concentration of at least 8 moles (preferably at least 12 moles) and the central region contains less than 5 moles of iodide, The sensitization of tabular silver bromoiodide grains can be confined to the central region of their centers without the use of adsorbed local controlling substances. Or, to state another point, in the case of selective epitaxial growth in the central grain region, the iodide present at the surface of the annular grain region can itself act as a local dominating material for the selective epitaxial growth. If the size of the central grain region is restricted relative to the laterally surrounding annular grain region, the area of sensitization can be restricted simply by such restriction. One of the distinct advantages of selective local sensitization in this manner is the central location of the sensitized site. In such a case, the diffusivity required for photoelectrons or photoholes to reach the sensitized site can be shortened. Therefore, holes and electrons can be trapped more effectively with less risk of their extinction.

This method of selective local sensitization can reduce the competition for photoelectron capture by reducing the number of sensitizing sites when the sensitizing sites work in the direction of positioning the latent image. Useful when deposited by epitaxial growth.

In another variation of the invention, the use of adsorbed locally dominant substances is unnecessary, and the tabular silver bromoiodide grains using tabular silver bromoiodide emulsions as described above are The grains are selected to have an iodide-poor central region which is itself an annular region. That is, such tabular grains contain a main central region of silver bromoiodide, a laterally surrounded central region having a negligible iodide content, and a laterally surrounded peripheral annular region. ing. As previously stated, the annular center region contains less than 5 moles of iodide, and the predominant center region and annular peripheral region each contain at least 8 moles of iodide, preferably at least 12 moles of iodide. The iodide-containing silver chloride is epitaxially grown on and substantially confined to portions of the major crystal faces of the tabular grains defined by the annular central region. . Through controlling the extent of the central annular region, the extent of epitaxial growth on the major faces of the tabular grains can be correspondingly controlled. Of course, if the amount of epitaxial growth of silver chloride is limited, epitaxy may not occupy all of the deposition surface area provided by the annular center region; It can be limited to 2.3 discontinuous sites within the region. In the absence of a central region of low iodide content, silver chloride can alternatively be provided at the corners of the tabular silver bromoiodide grains for epitaxial growth. It is surprising that silver chloride is preferentially deposited in the central region.

It is possible to deposit silver chloride in both the central and peripheral regions of the tabular grains, provided that the rate of silver chloride deposition can be sufficiently accelerated.

Silver salts can be sensitized by either acting as hole traps or electron traps, depending on the silver salt epitaxy and the composition of the tabular silver halide host grains. In the latter case, it is also possible for silver epitaxy to position the latent image region formed by the image-forming layer. Modifying compounds present in the epitaxial flame release process of silver salts, such as copper,
Compounds of thallium, lead, bismuth, cadmium, zinc, intermediate chalcodans (ie, sulfur, selenium, and tellurium), gold, and Group I noble metals are particularly useful in enhancing sensitization. When electron-trapping metal ions are present in the silver salt epitaxy, they are useful in assisting in the formation of the internal latent image. Silver chloride may be deposited at the center of high iodide silver bromoiodide tabular grains in the presence of modifying compounds, such as lead or iridium compounds, which assist electron trapping. After image extinction, internal latent image areas are formed in the sensitized areas of the tabular grains where the silver chloride epitaxy is doped.

In order to aid in the formation of the internal latent image in combination with the epitaxial deposition of the silver salt, there is another method which consists in carrying out a conversion of the phosphorus ionide after the epitaxial growth of the silver salt. For example, if the salt deposited by epitaxial growth is silver chloride, the salt can be modified by contacting it with a halide of low solubility, such as a bromide salt or a mixture of bromide and iodide salts. As a result, chloride in epitaxial deposits is replaced by bromide and, if present, iodide ions. It is believed that the defects on the crystal thus obtained are the source of internal latent image formation. Performing halide conversion on salt deposits by epitaxial growth is described, for example, in the above-cited U.S. Pat. No. 4,142,900.
listed in the number.

In the various embodiments of the invention described above, silver salt epitaxy is limited to discrete sites on the tabular host grains, such as the center or corners, or to form rings, such as peripheral rings, at the edges of the major crystal faces. can be done. If the silver salt epitaxy functions as an electron trap and therefore also positions the latent image sites on the grain, the epitaxy may be confined to discontinuous surface grain sites, such as the center of the major crystal faces, or to a tabular host. It is preferable to have the grain adjacent to the corner of the particle, in this case,
The opportunity for latent image regions to form in close clusters and therefore competition for photoelectrons is greater when latent image regions can be formed along the edges of tabular grains (tabular grains are formed into ring shapes by silver epitaxy). (which can occur if the object is enclosed).

Silver salt epitaxy on tabular host grains can act as an electron trap or as a hole trap, therefore, silver salt epitaxy acts as a hole trap and silver salt epitaxy acts as an electron trap. It turns out that complementary sensitizing conjugates can be formed in combination. For example, when using electron-trapping silver salt epitaxy, it is possible to selectively sensitize tabular host grains at or near the centers of the grains. Thereafter, hole-trapping silver salt epitaxy can be selectively deposited on a portion of the particle. In this case, a latent image is formed at the center of the electron trapezoid and f-type epitaxy site, and the sensitivity is further increased by the corner epitaxy (a photopressure hole that would otherwise inevitably annihilate photoelectrons) is formed at the center. is trapped). In particular, if we look at typical forms, as mentioned above, the central region contains less than 5 moles of iodide, and the remaining 9 of the main crystal planes are at least 8 moles-1
Epitaxial growth of silver chloride is carried out on silver bromoiodide tabular grains preferably containing 12 moles of iodide. Silver chloride is grown epitaxially in the presence of modifying compounds that aid in electron trapping, such as compounds that provide lead or iridium doping agents. Then hole tiger,! Silver salt epitaxy can be selectively deposited at the corners of host tabular grains or selectively as rings along the edges of the major crystal planes by the use of adsorbed localized materials. It can be attached. For example, silver thiocyanate or silver chloride containing a copper-based dogue agent can be deposited onto the host tabular grains. Other combinations are of course possible.

For example, when replacing the position of the modifying material as shown above, the epitaxy at the center can act as a hole trap, and the epitaxy at the corners of the host tabular grain can act as an electron trap.

Although epitaxial growth of silver salts has been described above in terms of selective local sensitization, it will be appreciated that controlled local epitaxial growth of silver salts can also be useful in other respects, e.g. The silver salt that can be epitaxially grown is an incubage of tabular grain emulsion.

The stability of the device can be improved. Such silver salts can also be useful in promoting partial grain development and amplification processing of nine dye images, as detailed below. Epitaxially grown silver salts can also reduce dye desensitization. Furthermore, such silver salts can also promote dye aggregation. this is,
This is possible by leaving most of the silver bromoiodide surface substantially free of silver chloride. This is because most of the aggregated dyes are adsorbed more effectively on the surface of silver bromoiodide grains than on the surface of silver chloride grains. Another advantage that can be realized here is improved developability. Furthermore, higher contrast can be achieved through localized epitaxy.

Conventional chemical sensitization can be carried out either prior to or in a subsequent step to the controlled localized epitaxial growth of the silver salt. When silver chloride and/or silver thiocyanate are deposited on silver bromoiodide, a significant increase in sensitivity can be achieved simply by selectively localized deposition of the silver salt. Therefore, to obtain photographic sensitivity,
It is unnecessary to carry out a chemical sensitization step in the conventionally used type of cellulose. On the other hand, additional sensitivity increases can generally be obtained if subsequent chemical sensitization is performed. One notable advantage here is that neither high temperatures nor long residence times are necessary in preparing the acclimatizer. If (1) the sensitivity can be improved in the epitaxial growth itself or (2) if the sensitization is directed to the epitaxial growth site, the amount of sensitizer can be reduced as needed. Further epitaxial growth of silver chloride without chemical sensitization resulted in substantially the highest sensitization for tabular silver bromoiodide emulsions. If silver bromide is grown epitaxially on silver bromoiodide, selective local deposition is followed by further chemical sensitization, which results in greater sensitivity (if conventional finishing times and temperatures are applied). can achieve an increase in

When using adsorbed locally localized substances that are themselves effective spectral sensitizers, such as agglomerating dyes, a spectral sensitization step following chemical sensitization is unnecessary. However, in various cases it is possible to perform spectral sensitization during or after chemical sensitization. If a spectral sensitizing dye is not used as the adsorbed local dominating substance, for example when aminoadi/dane (e.g. adenine) is used as such dominating substance, chemical sensitization is required if spectral sensitization is to be carried out. keep doing that. If the adsorbed local substance is not itself a spectral sensitizing dye, the spectral sensitizer can replace such local substance, or at least be in close enough proximity to effect spectral sensitization. In many cases, the particle surface must be accessible at a distance.
Even when adsorbed spectral sensitizing dyes are used as localized agents, it is still desirable to carry out a spectral sensitization step subsequent to chemical sensitization.

Additional spectral increasing dyes may be used in place of or supplemented with the spectral sensitizing dyes used as localizing agents. For example, when used over additional sensitizing dyes, additional spectral increasing dyes The spectral sensitization can be increased by increasing the spectral sensitization or, most preferably, by supersensitizing. Of course, it will be appreciated that it is not important whether the spectral sensitizer introduced after chemical sensitization can act as a local agent for chemical sensitization.

After controlled localized epitaxial growth, any conventional chemical sensitization method can be used. in general,
Chemical sensitization should be based on the composition of the deposited silver salt rather than the composition of the host tabular grains. This is because the location where chemical sensitization occurs is thought to be primarily at the site of silver salt deposition or perhaps directly adjacent to such a site.

The high aspect ratio tabular grain silver rhodanide emulsions of this invention can be chemically sensitized before or after formation of deposits by engineered taxial growth. Chemical sensitization is carried out by boiling activated gelatin as described in James (T.
April 1974* It@m 1200 LJune 1975 eIt@m13452m U.S. Patent No. 1.623,499
No. 1,673,522, collection 2.399,08
No. 3, No. 2,642,361, No. 3,297,4
No. 47 and No. 3,297,446, British Patent No. 1,
No. 315,755, U.S. Patent No. 3,772ρ31, U.S. Patent No. 3.761,267, U.S. Patent No. 3,857,711,
3,565,633, 3,901,714 and 3,904,415, and British Patent No. 1.
For example, pAg levels of 5 to 10. pH level 5-8. and temperature 30-80
C. using sulfur, selenium, tellurium, gold, platinum, palladium, iridium, osmium, rhodium, rhenium or phosphorus sensitizers or combinations of these sensitizers. Chemical sensitization is optimally performed as described in U.S. Pat.
No. 642,361 in the presence of a thiocyanate compound at a concentration of 2.times.10@-3 to 2 molar based on silver, and also in U.S. Pat. No. 2,521,926.
No. 3.021,215 and No. 4,054.4
No. 57 is carried out in the presence of sulfur-containing compounds of the type described in No. 57.

Finishing (Chemical Sensitization) Chemical sensitization can be carried out in the presence of modifiers. Finishing modifiers used may be present during the chemical sensitization process, such as, for example, azoindenes, azopyridazines, azapyrimidines, benzothiazolium salts, and sensitizers with one or more heterocyclic nuclei. It is a good compound known to suppress capri and increase sensitivity. Examples of finish modifiers are described in U.S. Patent No. 2.
No. 131,038, No. 3,411,914, No. 3
．． 554,757, Canadian Patent No. 3,565,631 and Canadian Patent No. 3,901,714, Canadian Patent No. 778,723
No. and Duff 4 y (Duffin) * Photo
ographieEmulslon, Ch@m1st
ry+ Focal Class (1966), New York e pp. 138-143. In addition to or as an alternative to chemical sensitization, US Pat.
No. 91,446 and U.S. Pat. No. 3,984,249, for example using hydrogen, and also as described in U.S. Pat.
．． No. 983,609 Res@arch D1aclos
ure* Vol, 136 m 1975 Ritsuki@It
@m13654s U.S. Patent Nos. 2518.698, 2,739,060, 2.743,182, 2,743,183, 3,026,203 and 3, 361,564 using reducing agents such as stannous chloride, thiourea dioxide, I-lyamines and amines such as
Reduction sensitization can be carried out by (less than) and/or high (e.g. greater than 8) treatments. U.S. Patent No. 3,9
Surface chemical sensitization can be performed, including subsurface sensitization as described in No. 17,485 and No. 3,966,476.

In addition to chemical sensitization, the high aspect ratio tabular grain silver halide emulsions of this invention can also be spectrally sensitized. Spectral sensitizing dyes can be used that exhibit absorption maxima in the blue and minus blue (ie, green and red) portions of the visible spectrum. Additionally, in special applications, spectral sensitizing dyes can be used to improve the spectral response beyond the visible spectrum.

For example, it is possible to use infrared absorption spectral sensitizers.

The silver halide emulsions of this invention can be spectrally sensitized using dyes from various classes. The classes of pigments used herein include cyanines, merocyanines, anchor cyanines and complex merocyanines (i.e. trinuclear+, tetranuclear- and polynuclear cyanines and merocyanines), oxonols, hemioxonols, styryl, merostyryl and streptocyanin. Contains I-limetin dye.

Cyanine spectral sensitizing dyes include, for example, quinolinium, pyridinium, isoquinolinium, 3H-indolium, benz[.]indolium, oxacillium, oxazolinium, thiazolium, thiazolinium, selenazolium, selenacillinium, imidazolium, imidazolinium, benzoxa Zolinium, benzothiazolium,
Benzoselenazolium, benzothiazolium, naphthooxacillium, naphthothiazolium, naphthoselenazolium, thiazolinium, dihydrothiazolium,
Two basic heterocyclic nuclei linked by a methine linkage, such as those derived from pyrylium and imidazopyrazinium quaternary salts, are included.

Merocyanine spectral sensitizing dyes include, for example, parbylic acid, 2-f opalbituric acid, rhodanine, hydantoin, 2-thiohydantoin, 4-thiohydantoin, 2-
Pyrazolin-5-one, 2-itsuxazolin-5-one, indan-1,3-dione, cyclohexane-1,3
-dione, 1゜3-dioxane-4,6-dione, pyrazoline-3,5-dione, pentane-2,4-dione,
Alkylsulfonylacetonitrile, malono-megatrile,
Included are those in which an acidic nucleus and a cyanine dye-type basic heterocyclic nucleus are bonded through a methine bond, such as those that can be derived from isoquinolin-4-one and hydrochroman-2,4-dione.

One or more spectral sensitizing dyes can be used. Dyes are known that have maximum sensitivity at wavelengths throughout the visible spectrum and have a wide variety of spectral sensitivity curve shapes. The choice and relative proportions of dyes depend on the region of the spectrum in which sensitization is desired and the shape of the spectral sensitivity curve desired.0 Overlapping spectra: Dyes with sensitivity curves are often It will show a combined shape curve tube whose sensitivity in wavelength is approximately equal to the sum of the sensitivities of the individual dyes. Therefore, by using a combination of multiple dyes with different maximum sensitivities,
A spectral sensitivity curve can be obtained with a maximum value midway between the maximum sensitivities of the individual dyes.

Multiple spectral sensitizing dyes can be used in combination, thereby producing supersensitization (Sup＠r Hatake・n5itizati
on), that is, in a certain spectral region, the sensitivity is greater than when one of these spectral sensitizing dyes is used alone at any lightness, and the enhancement resulting from the acidic effect of these spectral sensitizing dyes It is possible to achieve a spectral sensitization as large as 4. Supersensitization consists of selected combinations of spectral sensitizing dyes and other additives such as stabilizers and anti-capri agents, development accelerators, inhibitors, coating aids, brighteners and antistatic agents, etc. This can be achieved by Overview of supersensitization mechanisms (Revlsv @t th@Mechanis)
ms of! iwp@rs@msitlzatiom)
J, Ph*t@grapkls8*1@*m*
anl ICngln WORK*r1mg, Vo! ,1
The spectral sensitizing dyes described in 8s 19γ4, pci, 41g-430 also affect emulsions in other ways. In addition, spectral sensitizing dyes are described in U.S. Patent No. 2.131,
038 and 3,930,860, which act as halogen acceptors or electron acceptors, anti-capri agents or stabilizers, and development accelerators or inhibitors.

In a preferred embodiment of the present invention, the spectral sensitizing dye also acts as an adsorbed locally dominant substance during silver salt deposition or chemical sensitization.

Useful dyes belonging to this type are agglomerated dyes.

Such dyes exhibit increased light absorption due to bathochromic and hypsochromic effects as a function of their adsorption to the surface of the 710 silver grains.

Dyes that satisfy these criteria include, for example, T and H.

James+The Theory of the P
photographlcProe*ss+4 th
Ed, +ff Cumilla Millan. 77, Chasita-8 (especially F, Induced Co1or ah tinC
yanine and Meroeyanine Dy
es) and Chapter 9 (especially H, Re1ation
s Bejyeen DyeStructure an
d 5surface Aggrsgatlon) and F
, M. Hamor+Cyanine Dyej and
RelatedCompounds+The Willy and Sons.

1964, Chapter X■C especially F, Polyme
ri-zation and 5ensitizati
on of the 5 ocondType), which are well known in the art.

Spectral sensitizing dyes such as merocyanine, hemicyanine, styryl, and oxonol that form H-aggregates (hypsochromic effect-shift) are known in the art.

However, for these classes of dyes, J-aggregates (shifts due to bathochromic effects) are not common. Preferred spectral sensitizing dyes are cyanine dyes. This is because this dye exhibits either H-aggregates or J-aggregates.

One preferred form of the spectral sensitizing dye is a cyanine dye (
J aggregates). Such dyes are characterized in that two or more heterocyclic nuclei are bonded by bonds consisting of three methine groups.

The heterocyclic nucleus preferably includes a fused benzene ring to enhance J aggregation. Preferred heterocyclic nuclei for promoting J aggregation include quinolinium, benzoxacillium, benzothiazolium, benzoselenazolium,
These are benzimidazolium, naphthoxacillium, naphthothiazolium, and selenazolium quaternary salts.

Particularly preferred dyes for use as adsorbed local control substances are listed in Table 1 below.

Table 1 Preferred examples of adsorbed locally dominant substances AD-1 Anhydro-9-ethyl-3,3'-bis(3-sulfopropyl)-4,5,4'.

5'-Shihenzothiacalcyanine hydroxy AD-2 anhydro-5,5'-dichloro-9-ethyl-3,3'-bis(3-sulfobutyl)thiacarbocyanine hydroxide AD-3 anhydro-5,5' , 6,6'-tetrachloro-1,1'-diethyl-3,3'-bis(3-
Sulfobutyl)benzimidazolocal? Cyanine hydroxide AD-4 Anhydro'-5,5',6,6'-tetrachloro-1,1',3-)liethyl-3'-(3-sulfobutyl)benzimidazolocal is cyanine hydroxide AD-5 anhydro-5-chloro-3,9-diethyl-
5'-Phenyl-3'-(3-sulfopropyl)oxacardocyanine hydroxide AD-6 anhydro-5-chloro-3',9'-diethyl-57-phenyl-3-(3-sulfopropyl)oxa Cardecyanine hydroxide AD-7 anhydro-5-chloro-9-ethyl-5'-
Phenyl-3,3'-bis(3-sulfopropyl)oxacardecyanine hydroxide AD-8 Anhydro-9-ethyl-5,5'-diphenyl-3,3'-bis(3-sulfobutyl)oxacarbocyanine hydroxy AD-9 anhydro-5,5'-
Dichloro-3,3L bis(3-sulfopropyl)thiacyanine hydroxide AD-101, 1'-diethyl-2,2'-cyanine p
-) Luenesulfonate When recording blue light exposures in this technical field, the emulsion is typically Significant advantages can be obtained through the use of spectral sensitizers even in cases where the predominant absorption is found in the spectral region to which the spectral sensitizer exhibits natural sensitivity. For example, it is specifically recognized that benefits may be achieved through the use of blue spectral sensitizing dyes. Even when the emulsions of this invention are high aspect ratio tabular grain silver bromide and silver bromoiodide emulsions, very large increases in sensitivity can be obtained through the use of blue spectral sensitizing dyes. If an emulsion according to the invention is intended to be exposed in its native speed range, advantages in speed can be obtained by increasing the thickness of the tabular grains. For example, in a preferred embodiment of the invention, the emulsions are blue sensitized silver bromide and silver bromoiodide emulsions, and in such emulsions, the thickness is less than 0.5 micrometers and the diameter is at least 0.5 micrometers. The tabular grains, which are 6 micrometers in size, have an average aspect ratio of greater than 8:1, preferably at least 12:1, and account for at least 50 of the total projected area of the silver halide grains present in the emulsion. h, preferably 7096. Particularly preferably, it accounts for at least 90%.

Among the spectral sensitizing dyes useful for sensitizing silver halide emulsions are R.
Vol.

176. December 1978 Item 17643 +
There are some described in 5ec-tion m.

Conventional amounts of dyes can be used to spectrally sensitize emulsion layers that are non-tabular or contain low aspect ratio tabular silver halide grains. To realize the full benefits of the present invention, an optimum amount (i.e., at least 60% of the maximum photographic sensitivity achievable from the particles under possible exposure conditions)
Preferably, a sufficient amount of spectral sensitizing dye (sufficient amount to achieve the desired effect) is adsorbed onto the grain surfaces of the high aspect ratio tabular grain emulsion. The amount of dye used herein will vary based on the particular dye or combination of dyes chosen and the particle size and aspect ratio. It is known in the photographic art that optimal spectral sensitization is achieved when using organic dyes at monolayer coverages corresponding to about 25-100% or more of the total effective surface area of the surface-sensitive silver halide grains. Are known. That is, this refers to, for example, the adsorption of sensitizing dyes in photographic emulsions (West), etc.
nsitizlngDyes in Photogra
phic Emulsions)JJournal o
f phys, Chem, +Vo1.56+p, 10
65+1952; Spence et al. “De@sensitization of sensitizing dyes”
SensitizingDyes)J+Journal
of Physical and CollolCo
11oldChe+Vol, 56 + 46 + 1
June 948, pp.

1090-1103; and U.S. Pat. No. 3,979,213. The optimal dye density level is Mees+Theory of Photo
ogra-phic Process+ 1942,
Macmillan, pp-1067-1069 (supra).

Quite unexpectedly, high aspect ratio tabular grain silver halide emulsions that have been selectively locally sensitized in accordance with the present invention can be compared with similar high aspect ratio tabular grain silver halide emulsions ( It has been found that the film exhibits higher photographic sensitivity when compared with those in which chemical sensitization and spectral sensitization have been completed according to conventionally known techniques. The high aspect ratio tabular grain silver bromoiodide emulsions of the present invention exhibit higher speed-granularity relationships compared to those previously observed in the photographic field.

Although not necessary to achieve all advantages, emulsions according to the invention are preferably optimally chemically and spectrally sensitized according to typical practical manufacturing methods. This means that it is preferable to achieve a sensitivity corresponding to at least 60 degrees of the maximum Log sensitivity achieved from those particles in the sensitized spectral region under possible use and processing conditions. Here, Log sensitivity is 10
0100 (means 1-to, E in the formula is 0.
It is the exposure amount expressed in meters-cantreux seconds at a density of 1. Once the host tabular grains of an emulsion layer have been characterized, further product analysis and analysis can determine whether the emulsion layer of a product is optimally chemically and spectrally sensitized relative to comparable products from other manufacturers. This can be determined by performing performance evaluation. In achieving the sharpness advantages of the present invention, it is immaterial whether the chemical or spectral sensitization of the 10-gen recording emulsion is carried out efficiently or inefficiently.

F. Silver Image Formation Once high aspect ratio tabular grain emulsions have been formed, washed, and sensitized by the precipitation method as described above, they can be improved by incorporating commonly used photographic additives. When the preparation is completed, it is possible. These can then be applied in photographic applications where it is desired to produce silver images, such as conventional black and white photography.

If a photographic element having an emulsion according to the invention is intended to be used to form a silver image, the photographic ice must be sufficiently hardened so that no additional hardeners need to be incorporated during processing. can be done. By this hardening, it is possible to realize an increase in silver coverage i'4.

Alternative useful compound hardeners (pre-hardeners) are found in Research Disclosure, Volume 176, December 1978, Item 17643. Described in Section X.

Research Disclosure, Volume 176.

Incorporation of stabilizers, anti-capri agents, anti-kink agents, latent image stabilizers and similar additives into the emulsion layer and adjacent layers prior to coating, as described in December 1978, Item 17643, Section VI. In addition, it is possible to increase the minimum density (ie, capri) in negative-working emulsion coatings and to avoid instabilities that would otherwise increase the minimum density or reduce the maximum density in directly positive-working emulsion coatings. e, E
, ni, Mees *De theory op.
The Photographic Process, 2nd edition, Macmilla/.

1954, pp. 677-680, many of the anticapri agents effective in emulsions can also be incorporated into developers, and under a few general headings. If you classify it based on it, you can see.

When using aldehyde type hardeners, the emulsion layers can be protected with conventional anticapri agents.

In the case of the emulsions of this invention, they can equally be applied to photographic elements intended for the formation of negative or positive images. For example, photographic elements having emulsion layers such as those described herein are of the type that form either surface or internal latent images upon exposure and in which these latent images upon processing form a negative image. can be. In some cases, such photographic elements can be of a type that directly forms a positive image in response to a single development step. When composite grains of host tabular grains and silver salt epitaxy form internal latent images, surface caps can be imparted to the composite grains for the purpose of promoting direct positive image formation. In one particularly preferred form, the epitaxy is selected in a direction such that the silver salt epitaxy itself forms an internal latent image site (i.e., transports electrons inward) and, if desired, the surface capri Can be limited to salt epitaxy.

In another form, the host tabular grains can trap electrons internally, preferably with silver salt epitaxy acting as a hole drag. Superficially fogged emulsions can be used in combination with organic electron acceptors.

This applies, for example, to US Pat. No. 2,541,472, UK Pat.
305 Engine No. 3,501,306 and No. 3.501
, No. 307, Lisa → Disclosure, Volume 134,
June 1975, Item 13452, and in U.S. Pat. No. 3,672,900, U.S. Pat. The organic electron acceptor can be used in combination with a spectral sensitizing dye, or the former itself can be a spectral sensitizing dye, as described in US Pat. No. 3,501.310.

If an internally sensitive emulsion is used, a combination of surface couplers and organic electron acceptors can be used as described in US Pat. No. 3,501,311. However, in cases where it is desired to directly form a positive image, neither a surface coupler nor an organic electron acceptor is necessary.

Photographic elements having emulsions of the present invention may employ, in addition to the special features described above, conventional features such as those described in Research Disclosure, Volume 176, December 1978, Item 17643. can.

If photographic elements employing emulsions of the present invention are intended to be utilized in the field of radiography, the emulsions and other layers of radiographic elements may be cited hereby in Research Disclosure, Volume 184, August 1979, Item 18431. Emulsions of this invention as well as other commonly used silver halide emulsion layers, interlayers, overcoats, and subbing layers, if present in photographic elements, should be
It can be applied and dried as described in Disclosure, Volume 176, December 1978, Item 17643, Intestines.

According to established practice among those skilled in the art, the present invention
By blending the Suyckt ratio tabular grain emulsions with each other or with conventional emulsions, specific properties required of the emulsion layer can be met. For example, by blending multiple emulsions, the characteristic curve of a photographic element can be tailored to meet a given objective.

Blending can increase or decrease the maximum density achieved by exposure and processing, reduce or increase the minimum density, and adjust the shape of the characteristic curve between the foot and shoulder. For this reason, the emulsion according to the present invention can be cited in Research Disclosure, Vol. 176,
It can be blended with conventional silver halide emulsions such as those described in December 1978, Item 17643.1. It is also possible to blend emulsions such as those described in IgiF.

Photographic elements having emulsions according to the invention, in their simplest form, employ a single silver halide emulsion layer comprising a high aspect ratio tabular grain emulsion according to the invention and a photographic support. It has been recognized that more than one silver halide emulsion layer, as well as overcoats, subbing layers and interlayers, may be advantageously included.Instead of blending the emulsions as described above, the emulsions to be blended may be A similar effect can be achieved by coating each as a separate layer. Coating the emulsion layers separately to obtain exposure latitude is well known in the photographic art and is described by Zellkman and Levl. ), Making and Coating Photographic Emulsions, Focal Press.

1964, pp. 234-238, U.S. Patent No. 3.6
No. 62,228 and British Patent No. 923,045. Additionally, it is well known in the photographic art that photographic speed can be increased by coating fast and slow silver halide emulsions in separate layers rather than blending them. Typically, the faster emulsion layer is coated closer to the source of exposing radiation than the slower emulsion layer. This technique can be applied to the preparation of three or more stacked emulsion layers. Such layer configurations can be utilized in the practice of the present invention.

The layers of the photographic element can be coated on a variety of supports. Typical photographic supports include polymeric films, wood fibers (
(e.g. paper), metal sheets and foils, glass and ceramic support elements, which are characterized by their adhesion, antistatic properties, dimensional stability, abrasion resistance, hardness, frictional properties, and wear resistance of the support surface. One layer can have more than one subbing layer to improve anti-fouling properties and/or other properties. These supports are well known in the art, eg, Research Disclosure.

Volume 176, December 1978, item 17643, listed on the top of the layer.

The emulsion layer or layers are usually, but need not be, coated as a continuous layer on a support having opposing planar major surfaces. The emulsion layer can be applied as a plurality of laterally displaced layer segments onto a flat support surface. When a single or Fi, m number of emulsion layers is used as a segment, it is desirable to use a microcellular support.A useful microcellular support is described in International Publication No. W.
No. 080101614 (published Aug. 7, 1980; corresponds to Belgian Patent No. Flf@881,513, Aug. 1, 1980) and U.S. Pat. No. 4,307,165. A microcell can have a width of 1 to 200 micrometers and a depth of up to 1000 micrometers. In general, in the field of ordinary black and white photography, especially when enlarging photographic dimensions, the size of the microcell should be at least 4 micrometers, and the depth should be 200 mm.
Less than a micrometer is preferred, with the best size being about 10-100 micrometers both in width and depth.

Photographic elements employing emulsions of this invention can be imagewise exposed by any conventional method. See Research Disclosure, Item 17643, Section M above.

The photosensitive silver halide contained in the photographic element can be used in an alkaline medium or photographic medium following exposure to light. A visible image can be formed by processing in a conventional manner by combining the iron halide with an aqueous alkaline medium in the presence of a developer contained in the element.

Once the silver image has been formed in the photographic element, it is common practice to fix the undeveloped iron halide. The high 7 spectral tabular grain emulsions of this invention are particularly advantageous in that fixing can be completed in a much shorter period of time, thereby allowing accelerated processing.

03 Dye Image Formation The photographic elements and techniques described above for forming silver images can be readily adapted to form colored images using dyes. In perhaps the simplest technique for obtaining a projectable color image, conventional dyes can be incorporated into the support of the photographic element and silver image formation can be carried out as described above. In the areas where the silver image is formed, the photographic element is substantially opaque to light, and in other areas it is transparent, corresponding to the color of the support. Colored images can be easily formed in this way. This same effect can also be achieved by using a separate dye filter layer or an element with a dye filter element and a transparent support element.

Silver halide photographic elements can be used to form dye images by selective destruction or formation of dyes. The photographic elements described above for forming silver images may contain dye image-forming agents such as color couplers ( Dye images can be used to form dye images by using developers containing dye images (7 ohmers). In such a form, the developer includes a color developing agent (eg, an aromatic primary amine) that, in oxidized form, is capable of reacting (coupling) with the coupler to form an image dye.

Optionally, dye-forming couplers can also be incorporated into the photographic element in conventional manner. Dye-forming couplers can be incorporated in different amounts to achieve different photographic effects. For example, in connection with silver coverage, the concentration of coupler can be limited to less than the amounts normally used in fast and moderate speed emulsion layers.

Pigment-forming couplers are typically used to produce subtractive primary colors (
(i.e., yellow, magenta and cyan) and these couplers are non-diffusive colorless couplers. Dye-forming cubes with different reaction rates in a single or a number of separate layers can be used to achieve the desired effect in a particular photographic application.

Dye-forming couplers can be combined with, for example, development inhibitors, accelerators, bleach accelerators, developing agents, silver halide solvents, toning agents, hardeners, capric agents, anti-capri agents,
Photographically useful fragments such as competitive couplers, chemical or spectral sensitizers and desensitizers can be released. Development inhibitor releasing (DIR) systems are well known in the photographic field. Furthermore, oxidatively cleaved DIR
Compounds can also be used. For example, silver halide emulsions with relatively poor photosensitivity, such as Lippmann emulsions, have been utilized as interlayers and overcoat layers to prevent or inhibit migration of development inhibitor fragments.

The photographic element can be incorporated with coloring dye-forming couplers and/or competing couplers such as those used in forming layered masks for negative color images. Photographic elements can further include conventional image dye stabilizers. All of this is in Research Disclosure, Volume 176, December 1978, Item 176.
43, Section ■.

A dye image can be formed or amplified by employing a method of using an oxidizing agent in the form of an inert transition metal ion complex in combination with a dye image-forming reducing agent. Photographic elements are particularly suited for forming dye images by such methods. When the tabular grain silver halide emulsions of this invention contain iodide, amplification reactions, particularly those utilizing iodide ions for catalyst poisoning, can be carried out.

A dye image can be formed in a photographic element by selective destruction of the dye or dye solécasa (precursor), such as by a silver-dye-bleach process.

Removal of developable silver by bleaching is a common method in the art of forming dye images in silver halide photographic elements. Removal of such silver can be facilitated by incorporating bleach accelerators or their zolecas into processing solutions or certain layers of the photographic element. In some cases, especially when amplifying dye images as described above, the amount of silver formed by development is small compared to the amount of dye produced. Therefore,
Silver bleaching is omitted with virtually no visible effect.

In still other applications, a silver image is retained and a dye image is utilized to enhance or supplement the density provided by the silver image. When silver image formation is enhanced with dyes, it is usually desirable to use a single dye that is neutral or a combination of dyes that can produce an overall neutral image. □ Margin below H0 Partial grain development Some types of light detection confectionery (for example, semiconductors in video cameras, etc.) are silver halide photographs! ! It has been recognized and reported in the photographic field that detection quantum efficiency is superior to the original detection quantum efficiency.

A study of the fundamental properties of conventional silver halide photographic elements has shown that this is primarily due to the dual on-off % properties of individual silver halide grains, rather than the low quantum sensitivity of the silver halide grains. has been done. This means that
For example, Shav S., "Multi-Level Grain and Ideal Photography, Detector", Fairing, Vol. 16, 43.1972.
May 76, pp. 192-200. Here, the on-off % property of silver halide grains means that once a vertical image center is formed on the silver halide grains, the grains can be completely shaped.Usually, development is independent of the amount of light hitting the particle, which is greater than the latent image formation limit. Whether the silver halide grain absorbs many photons and forms several latent image centers or only absorbs a minimal number of photons and forms a single latent image center ti. , silver halide grains yield identical products upon development.

For example, in the case of the high 7 spectral tabular grain emulsions of this invention, upon exposure, fli image centers are formed in and on the silver halide grains of the emulsion. In some particles, only a single latent image center is formed, in some particles, many latent image centers are formed, and in some particles, no latent image center is formed.

However, the number of latent image centers formed is related to the amount of radiation exposure. Because tabular grains have a relatively large diameter,
In addition, their sensitivity is relatively high because the sensitivity-granularity relationship is high (this is especially true for grains formed from silver bromoiodide, which is chemically and spectrally sensitized substantially uniformly in i/%). expensive. Since the number of latent image centers in or on each particle is directly related to the amount of radiation that the particle is exposed to, the potential for high detection quantum efficiency is high, provided that such information is not lost during development. exists.

In a preferred embodiment, each latent image center is developed, and the size of the latent image center increases significantly upon complete development of the silver halide grains. This can be done by t-blocking the development of the iron halide at an early stage (normally), well before optimal development is achieved in normal photographic applications. DIR as another technique
There are techniques using Kagura and color developers. The inhibitor released during fogging can be used to completely prevent the development of silver halide grains. Another method of carrying out this process uses a self-suppressing developer. A self-inhibiting developer is one that begins developing the silver halide grains but itself stops developing before the silver halide grains are completely developed. A preferred developer of this type is Neuberger (N*ub@rg@r)
*, [7 Normal Concentration Expansion, Work 2 Ecto: 7 Inverse Relay Interchange,) Between the Rates Opudevello, Gment and...
Deperonno Mother - Concentration Rose Op-S19
Volume, No. 6, November-December 1975, pp-327-
332, a p-phenylenediamine-containing self-inhibiting developer. Stop development and use FiDIR again.
By carrying out the development tube in the presence of a coupler, it is possible to completely prevent the development of silver halide grains which have a longer development induction period than adjacent developer grains. However, using a self-suppressing developer has the advantage that development is not suppressed until after the development of individual particles has occurred to some extent.
It is further recognized that partial grain development Yr can be obtained or assisted based on the difference between the developability of the iron salt by epitaxial growth and that of the silver halide forming the host tabular grains. US Patent No. 4
, 094,684 discloses a technique for achieving partial grain development through selection of developer and body conditions.

When the development of the latent center is promoted, a large number of silver nuclei are generated. The size and number of these silver nuclei depend on the exposure of each particle.
Proportional to 1 blind. To the extent that the preferred self-inhibiting developer includes a color developing agent, the resulting oxidized developer can be reacted with a dye-forming agent to form a dye image. However, since only a limited amount of silver halide is developed, the amount of dye that can be formed in this way is also limited. Techniques to eliminate such limitations and achieve maximum dye formation, but to ensure proportional production of dye concentration to degree of exposure, include the use of peroxides or transition metal ion complexes as oxidizing agents. , also using a dye image-forming reducing agent, such as a color developer, #! There is a technique to perform a reduction reaction. When surface latent image centers are formed in the silver halide grains, these centers themselves provide sufficient silver to catalyze the dye image amplification reaction. Therefore, although the step of accelerating the latency*1 by development is preferable, it is not essential. Any residual silver in the solution is removed by bleaching.

The photographic image obtained is a two-point distance (
As a result, the detection quantum efficiency of the photographic element is very high; as mentioned above, redox reactions can increase the level of graininess, but high photographic sensitivity can be easily obtained.

Graininess can be reduced by using microcellular support tubes as taught in International Publication No. WO 80101614, cited above. The perception of graininess is not limited to the size of individual image dye clouds. produced by the randomness of their positions. The sense of graininess can be reduced by applying the emulsion t-m to the regularly arranged microcells formed by the support, and applying the resulting color St-i uniformly over each microcell. can.

Although partial grain development has been described above with particular reference to the formation of dye images, it is equally applicable to the formation of silver images. By completing development before the particles containing the latent image areas are completely developed, the formation of visible graininess in the silver image during the development stage of the silver image can be reduced.

Compared to whole grain development, partial grain development VC allows a larger number of pot centers or specks to be produced, thereby reducing the perception of graininess at a given concentration. In addition, in the case of color IA image formation performed by blending couplers, the same effect can be obtained by limiting the coupler concentration so that the amount of coupler is less than the stoichiometric amount normally used for I.logn/j-silver. A reduction in graininess can be achieved. Yoma! ! The amount of silver handled in the base must be nine times higher than the initial level to achieve maximum Fi density levels for partial grain development compared to whole grain development, but the silver halide that is not developed is fixed and can be removed by recovery, so the net consumption of silver is not necessarily increased. Partial grain 3J! in silver imaging of photographic elements with microcellular supports! By adopting *, color**
The graininess of the silver image can be reduced in the same way as described above with regard to shadow formation. For example, the silver halide emulsion according to the invention is placed in a microcell arranged on a support and after imagewise achromatic irradiation. If developed, a large number of fine silver nuclei are formed in proportion to the radiation dose received during exposure and the number of latent image sites formed. Silver Core Coverings J? is small compared to that achieved by whole-grain development;
The undeveloped silver halide is fixed and removed, and the silver present in the microcells is re-halogenated (EIL), followed by physical development of the silver onto a uniform, aligned layer of physical development nuclei contained in the microcells. The covering power can be increased by increasing the covering power.Because physically developed silver on fine nuclei can have a much higher density compared to chemically developed silver, a much higher maximum density can be obtained. In addition, physically developed silver forms in each microcell with uniform my, which reduces graininess, because of the random occurrence of silver concentration. This is because it replaces the regularity of microcerno mother turns.

! The high aspect ratio tabular grain emulsions of the present invention are optionally sensitized as described above within the spectral region, and the sensitivity of the emulsion within that spectral region is When compared with the spectral region in which the original sensitivity tW would be expected to be due to its halide composition, it was found that there is a much larger sensitivity difference than previously observed in ordinary emulsions. In the case of silver bromide and silver bromoiodide emulsions, inadequate separation in the blue and green or red sensitivities of these emulsions has long been a drawback in multicolor photography. The difference in spectral fineness of silver bromide and silver bromoiodide emulsions can be used to advantage; this will be explained below with particular reference to multicolor photographic elements.
1! Clarify/However, M5 with? It should be noted that this is merely an example of an application. The increased spectral sensitivity difference brought about by the present invention is also useful in multicolor photography. It is not limited to emulsions either. It can be appreciated that the spectral sensitivity differences of the emulsions of this invention can be observed in photographic elements consisting of a single emulsion layer; for example, in the case of silver chloride and silver chlorobromide emulsions, the inherent blue sensitivity is sufficiently low. It is known that these emulsions can be used in multicolor photography to record green or red light because they have a high chromatography and that there is no need to provide protection from blue light exposure. Although there are
The advantage of increased sensitivity differences between various spectral regions exists in other applications, for example, when high aspect ratio tabular grain silver chloride emulsions are sensitized to the infrared and images in the spectral sensitized region are In the case of optical exposure, processing can be carried out under light irradiation with only a smaller increase in the minimum density. This is because in the emulsions according to the invention there is a reduction in sensitivity in the spectral region that does not involve spectral sensitization.

J. Multicolor Photography The present invention can be used to form multicolor photographic images. In general, any conventional multicolor imaging element containing at least one nologonated silver emulsion layer can be used to form high color photographic images according to the present invention. The present invention is applicable to both additive and subtractive multicolor imaging processes, which can be improved only by adding or substituting aspect ratio tabular grain emulsions.

Firstly, to describe the application of the invention to additive multicolor image formation, a filter array comprising blue, green and red filter elements insertable in combination with a photographic element comprising an emulsion according to the invention capable of forming a silver image. can be used. chromatically sensitized high aspect ratio tabular grain emulsions of the present invention forming one layer of a photographic element are subjected to imagewise exposure through an array of additive primary color filters to form a silver image; When viewed through the filter array, a polychromatic image is seen.

It is best seen when such an image is projected. Therefore,
The application of the present invention to multicolor photographic elements of the type in which photographic elements and filter arrays both possess or share a transparent support and form a multicolor image by a combination of subtractive primary image-forming dyes is particularly advantageous. It can also bring benefits.

Such photographic elements consist of a support and usually at least three sets of overlapping silver halide emulsion layers that separately record blue, green and red exposures as yellow, magenta and cyan color images, respectively.

The invention generally applies to any multicolor photographic photograph of this type containing at least one high aspect ratio tabular grain silver halide emulsion! ! Further advantages are provided when using high aspect ratio tabular grains silver bromide and silver bromoiodide. Accordingly, while preferred embodiments incorporating silver bromide and silver bromoiodide emulsions are described below, high aspect ratio tabular grain greens having any halide composition may optionally be used unless otherwise specified. , the multicolor photographic element can have the characteristics of the photographic elements described above.

In one particularly preferred form of the invention, negative blue sensitizing high aspect ratio tabular grain silver bromide or silver bromoiodide emulsions are present in the triplet blue, green and red recording emulsion layers of a multicolor photographic element. The green grain forms at least one of the emulsion layers in which red light is to be recorded. In addition, it is arranged to receive neutral light in blue light at 5500°. The relationship between blue and negative blue light received by this emulsion layer can be expressed as Δ1ogE.

ΔlogE m log)T−1ogEll, where ET is the logarithm of the exposure to green or red light that the tabular grain emulsion is to record, and 1ogE,
#'i is the logarithm of the amount of blue light exposure simultaneously received by the tabular grain emulsion. In either case, the exposure amount EFi
Unless otherwise specified, it is expressed in cm-candle-seconds.

In the practice of the present invention, Δ1ogE FiO, less than 7 (
Fio, 3 to 1) can still be obtained and still obtain acceptable reproduction images of multicolored objects. This is surprising considering the high proportion of emulsion grains present in the sample. If the high aspect ratio tabular grain silver bromide or silver bromoiodide emulsions used in this invention are replaced by equal negative nontabular or low aspect ratio tabular grain emulsions having similar halide compositions and average grain diameters, Color distortion due to green or red sensitization of silver bromide and silver bromoiodide emulsions reduces the average grain diameter, which would result in color distortion that is higher and usually exceeds the acceptable level limit if green or red sensitization occurs. Although it is known in the photographic art that reduction in particle diameter can be achieved by reducing the particle diameter, the maximum achievable photographic sensitivity is limited.

The present invention not only advantageously separates blue and negative blue sensitivity, but also particularly preferred embodiments of the invention achieve such advantages without any effect on the maximum achievable negative blue photographic sensitivity. At least the negative blue recording emulsion layer is composed of the silver bromide or silver bromoiodide emulsion according to the present invention. The blue recording emulsion layer in the triple emulsion layer may also advantageously be comprised of a high 7 spectral tabular grain emulsion according to the invention. In a particularly preferred form of the invention, each of the 35 emulsion layers has In yet another preferred embodiment of the invention, the tabular grains present with a thickness of less than 0.3 micrometers have an average grain diameter of at least 1.0 micrometers, preferably at least 2.0 micrometers. I of at least 180 multicolor photographic elements
A multicolor photographic element having an emulsion according to the present invention has a high aspect ratio tabular grain green and ('19) red emulsion layer that is protected from light by evening light.
It is not necessary to place a layer of yellow filter between these layers and the exposure source in order to expose the red or green recording emulsion of the photographic element to be exposed to daylight. The layer density can be reduced to a lower concentration than the yellow filter single layer that has been used heretofore to protect the gold from blue light. In one particularly preferred form of the invention, no blue recording emulsion layer is interposed between the green and (or) red recording emulsion layer of the triplet of emulsion layers and the exposing radiation source, thus the photographic element has substantially no blue absorbing material between the green and/or red emulsion layer and the incident exposing radiation.

Only one green or red recording high annuvect ratio tabular grain silver bromide or silver bromoiodide emulsion as described above is required, but the multicolor photographic Ij & element is exposed to blue, green and red light tubes respectively. Contains at least three separate emulsion layers for. Other than the required high aspect ratio tabular grain green or red recording emulsion layers, the emulsions may be of any conventional type. Various commonly used emulsions may be cited previously in Research Disclosure, Item 176.
43, Section 1. Preferably all emulsion layers contain silver bromide or silver bromoiodide tabular host grains.
In a highly preferred form, at least one green recording emulsion layer and at least one red recording emulsion layer are comprised of high aspect ratio tabular grain emulsions of the present invention. If two or more emulsion layers are arranged to record the green and/or red portions of the spectrum, it is desirable to incorporate the above-mentioned high aspect ratio tabular grain emulsion at least in the high-speed emulsion layer. Of course, it will be appreciated that it is not essential to the invention, but preferred, that all blue, green and red recording emulsion layers of a given X element be comprised of tabular grains as described above.

Invention/ri Multicolor photography with blue, green and red recording emulsion layers exhibiting a wide range of sensitivities and contrasts! High aspect ratio tabular grain emulsion silver or silver bromoiodide emulsion layers that are spectrally sensitized to green or red used in the present invention are relatively insensitive to blue; The green and (also 11) red recording emulsion layers can be placed anywhere within the multicolor photographic element independently of the other emulsion layers, and the precautions traditionally taken to prevent them from being exposed to blue light. No need to pay MT.

The Fi% of the present invention can be applied to multicolor photographic elements in which colors are to be accurately reproduced by daylight exposure. Such TIG photographic elements have a % mold resistance of forming blue, green and red light records exhibiting virtually comparable contrast and limited sensitivity variation when exposed to a 5600°K (daylight) source. Here, the term "comparable contrast" means that the contrast of the blue, green and red records differs by less than 201 (preferably by less than 10) with respect to the contrast of the blue record. means. Limited sensitivity change for blue, green and red distributions is 0.31ogE
(where sensitivity variation refers to the greater of the two differences between the sensitivity of the green and red records and the g degree of the blue record).

The measurements of contrast and leg IIA degrees necessary to establish the above relationships for photographic elements according to the present invention demonstrate that the photographic elements, at a color temperature of 5500° K. This can be done by exposing the light through a step wedge and processing the photo under the processing conditions available when using a suitable case. American Standard PH2,1-1952 (American Standards Institute wavelength 435.8 ntn O'p!r color light, wavelength 546.
By measuring the blue, green and red densities of the photographic element for the transmission of green light at 1 nm and red light at wavelength 643.8 nm, it is possible to plot the blue, green and red characteristic curves of the photographic element. If the photographic element has a reflective support rather than a transparent support, the transmission 11
Reflection density can be used instead of once. The sensitivity and contrast can be determined from the blue, green and red characteristic curves using techniques well known in photographic applications. Multicolor photographs used in different photographic applications do not necessarily support the specific sensitivity and contrast measurement methods employed, as long as each of the blue, green and red records are measured similarly for comparative purposes! ! Standard sensitometric measurement techniques for native species are published by ANSI K. One representative publication is American Standard PH2, 21-1979, PH2, 47-1979.
and PH2, 27-1979.

The all-emulsion multicolor photographic element of the present invention, which is capable of accurately reproducing color in daylight and no-light conditions, has considerable advantages over conventional photographic elements exhibiting the above-mentioned properties. , depending on the limited blue sensitivity of the tabular silver bromide or silver bromoiodide emulsion layers that are spectrally sensitized to green and red, the blue sensitivity of the blue recording emulsion layer minus the blue sensitivity of the blue recording emulsion layer. Can be separated. Depending on the particular application, the utilization of tabular grains in the green and red recording emulsion layers can itself produce a desired amount of separation in the blue color of the blue and minus blue recording emulsion layers.

In some applications, commonly used blue sensitivity separation techniques can be used to dramatically enhance the blue sensitivity separation of blue and minus blue recording emulsion layers to compensate for the blue sensitivity separation afforded by the presence of high-density tabular grains. For example,
If the most sensitive green fencing emulsion layer is located closest to the ttm optical radiation source, and the most sensitive blue recording emulsion layer is located furthest from the tm optical radiation source, blue and green recording The blue sensitivity separation of the emulsion layers (although they differ by an order of magnitude r 1.01 og if the emulsions are coated and exposed separately) is effectively reduced by such a layer arrangement. be able to. This is because the green recording emulsion layer accepts all the blue light during exposure, but the green recording emulsion layer and other overlying layers absorb or reflect some of the blue light before it reaches the blue recording emulsion layer. It is. In such a case, by incorporating a high proportion of iodide in the blue recording emulsion layer, it is possible to compensate for the increased blue sensitivity separation of the blue and minus blue recording emulsion layers in the tabular grains. If the blue recording emulsion layer is located closer to the main exposure radiation source than the minus blue recording emulsion layer, a limited concentration of yellow filter material coated between the blue and minus blue recording emulsion layers may be utilized to
Blue and minus blue separation can be increased.
However, as long as the conventional sensitivity separation technique itself provides a value that approximates the difference in magnitude present in the blue sensitivity separation, it is possible to utilize the conventional sensitivity separation technique as has heretofore been required in the field of photography. It is not necessary to do so. However, the above is not excluded if anomalous large blue and negative blue sensitivity separations are desired for a particular application; therefore, multicolor photographic elements according to the invention may be exposed under balanced lighting conditions. It allows for accurate reproduction of image colors when photographed, and also provides a much wider range of choices in the configuration of photographic elements than was previously possible.

Multicolor photography is often described in terms of color-forming layers. The most ordinary multicolor photo! ! The element contains three overlapping nine color-forming layer units, each of which has at least one color-forming layer unit capable of recording a different one-third of the spectrum and capable of producing complementary subtractive primary dye images. Contains one 7.silver rhodanide emulsion layer. That is, the blue, green, and red recording color-forming layer units used to produce yellow, magenta, and cyan dye images, respectively, do not necessarily have to be present in any of the color-forming layer units. , or can be fed entirely from the processing solution. When a chromophore-forming aITJ material is provided in a photographic element, it can also be located in an emulsion layer or positioned to receive an oxidizing developer or electron transfer agent from an emulsion layer of the same color forming unit. can be arranged in layers.

A fogged bran pencil, which is commonly used to prevent color degradation due to migration of oxidizing developer or electron transfer agents between color-forming layer units, is taught in U.S. Pat. No. 2,937,086. Emulsion as shown ~
and/or in intermediate layers between adjacent color-forming layer units as described in U.S. Pat. No. 2,336,327.

Each color forming layer unit can include a single emulsion layer, but often 2.3
or more emulsion layers having different photographic sensitivities are provided. Desired RII sampling is achieved by combining multiple emulsion layers with different sensitivities in a single layer.
If it is not allowed to be placed in the color-forming layer unit, single-layer
It is common to provide a plurality (usually 2 or #/'i3) of blue, green and/or red recording color forming layer units in the photographic element. It is unique to photographic elements having emulsions of the present invention that they include at least one green or red recording emulsion layer containing bromoiodide steel grains to allow an increased proportion of blue light to be received during the imagewise darkness of the photographic element. It is a 1% mark. To allow an increased proportion of blue light to reach the high aspect ratio tabular grain emulsion layer, the absorption of blue light by an overlying layer of yellow filters may be reduced or
Or, preferably, no yellow filter layer is placed thereon at all.Also, the chromogenic layer containing a high aspect ratio tabular emulsion is also increased by placing it close to the source of optical radiation. An example of how a green and red recording color-forming layer unit containing high aspect ratio tabular grain emulsions, respectively, can be allowed to reach a high aspect ratio tabular emulsion layer is a blue recording layer. The color-forming layer 22, can be placed closer to the exposing radiation source than the chromogenic layer 22.

The multicolor photographic element according to the present invention satisfies the above requirements.
It may be in any commonly used form.

Roces, Focallus, New York.

p, 211 m Any of the six possible layer configurations listed in Table 27m can be employed. To explain simply and clearly, in the process of preparing conventional multicolor non-rodanized photographic elements, such photographic elements are sensitized to the negative color growing portion of the spectrum and exposed prior to other emulsion layers. One or more high aspect ratio tabular grain emulsion layers positioned to receive radiation can be provided. However, in most cases, the layer structure is modified as necessary, and the conventional negative blue recording emulsion layer is replaced with one or more high aspect ratio tabular grain negative color recording sickle emulsion layers. Preferred layer configurations will be described below, so that the present invention can be fully understood from these descriptions.

In the above layer structure, B'-G and R represent the conventional TIG blue, green and red recording color forming layer units, respectively; , indicates one or more emulsion layers comprising a high aspect ratio tabular grain silver bromide or silver bromoiodide emulsion as specifically described above: chromogenic l-units) prior to B, G or R; B, written as B, indicates that the photographic sensitivity of the color-forming layer unit is greater than the sensitivity of at least one other color-forming layer unit that records exposures of the same -IA in the spectrum in the same layer configuration; Color-forming property 1 unit) S written before B, G or R indicates that the photographic sensitivity of the color-forming layer unit is at least 1 unit that records an exposure of the same 1/3 of the spectrum of the same layer structure.
It exhibits lower sensitivity than the other two color-forming layers; IL represents an intermediate layer containing scavenger but substantially free of yellow filter material. Each fast or slow chromogenic layer unit has a photographic sensitivity that differs from other chromogenic layer units recording exposures in the same third of the spectrum as a result of its position in the layer configuration, inherent speed characteristics, or both. can have.

In the layer structures shown in I to ■, the position of the support is not shown. In accordance with conventional practice, in most cases the support will be positioned furthest from the exposing radiation source, ie at the bottom of each layer arrangement, if the support is colorless and specular, i.e.
If transparent, the support can be placed between the exposure source and the described arrangement. Generally speaking,
The support can be placed between the exposure source and any color-forming layer unit in which the light transmitted by the support is to be recorded.

Returning now to layer structure (1), this photographic element is substantially free of yellow filter material. However, according to the prior art for elements containing filter materials, the color recording chromophoric layer unit is located closest to the source of exposing radiation. In a simple form, each color forming layer enit consists of a single silver halide emulsion layer. In another form, 2.3 or more different silver heronide emulsion layers can be combined into each color forming layer unit. When comparing the triple emulsion layers, one of which has the highest sensitivity, to each other, it is desirable that their contrast be substantially comparable;
Further, it is desirable that the photographic sensitivities of the green and red recording emulsion layers are less than the photographic sensitivity of the blue recording emulsion layer by 0.31 ogt. When two, three or more different emulsion layers with different sensitivities are present in each color-forming layer unit,
It is desirable that there be 2.3 or more triplet emulsion layers in layer configuration I with a given contrast and speed relationship. The absence of a yellow filter material directly below the blue recording color forming layer unit increases the photographic sensitivity of the color developing recording color forming layer unit.

It is not essential that the intermediate layer in the layer composition be substantially free of yellow filter material. Smaller amounts of yellow filter material than conventionally used amounts can be placed between the blue and green recording color forming layer units without departing from the teachings of the present invention. Additionally, less than the amount commonly used of filter material may be incorporated into the intermediate layer separating the green and red recording color forming layer units without departing from the invention.

When using a conventional amount of yellow filter material, the red recording color-forming layer unit is not limited to the above-mentioned tabular silver bromide or silver iodide sites, but may be any conventional one as long as contrast and sensitivity are considered. Any form can be adopted.

In order to avoid duplication, only the features that distinguish layer configurations 1 to 2 and layer configuration I will be specifically explained.

In layer structure 11, in the same coloring layer unit), 1
Rather than a combined high-speed and low-speed blue, red or green recording emulsion layer, two separate blue, green and red recording color columnar layer units are provided.

Only one or more emulsion layers of the fast color forming layer unit must contain the aforementioned tabular silver bromide or silver iodide grains. The low sensitivity green and red recording chromophoric layer units, due to their low sensitivity and the fact that the high sensitivity blue recording chromophoric layer unit is placed on top, allow blue light exposure without the use of yellow filter materials. be properly protected from Of course, this does not preclude the use of high aspect ratio tabular grain silver bromide or silver bromoiodide emulsions in the emulsion layers of the low speed green and (ti is) red recording color forming layer units. When a high-sensitivity red recording color-forming layer unit is placed on a low-sensitivity green recording color-forming columnar layer unit, US Pat. ，
Increased sensitivity is achieved as taught in US Pat. No. 6,222,923, US Pat.

Layer structure (1) differs from layer structure (1) in that the blue recording color-forming layer unit is disposed farthest from the exposure source. Therefore, the green recording color forming layer 22y) is closest to the light source, and
A red recording color forming columnar layer unit is placed relatively close to the light source. This layer structure is advantageous for forming a high-quality multicolor image with high sharpness. This green color is due to the fact that the green color-forming layer unit, which makes the most important visual contribution to the formation of a polychromatic image, is located closest to the exposure source and there is no light-scattering upper layer formed above it. The brass chromogenic layer unit is very! A one-sided image can be formed.

The red-recording chromophoric layer unit, which makes the next most important visual contribution after the formation of polychromatic hawks, passes only through the green-recording chromophoric layer unit and can therefore be scattered throughout the blue-recording chromophoric layer unit. Accept no light.

Although the blue chromogenic r-units suffer compared to the case of layer configuration I, the loss in sharpness does not offset the advantages of the green and red chromophoric layer units. This is because the multicolor 1' of the blue recording color forming layer unit
This is because the visual contribution to the elephant is not very important.

Layer configuration V is an extension of the layer configuration V, with green and red color-forming layer units enriched separately in high-speed and low-speed high-aspect grain emulsions. Layer structure V differs from layer structure (2) in that an I color recording color forming layer unit is additionally provided on the low sensitivity green, red and T color recording color forming layer units. The high aspect ratio tabular grain silver bromide or silver bromoiodide emulsion described above is used in the high sensitivity blue color forming unit. In this case, since this high-sensitivity blue recording color-forming layer unit absorbs blue light, the proportion of blue light reaching the low-sensitivity green and red recording color-forming layer units is reduced.

In a variation, it is not necessary to use high aspect ratio tabular grain emulsions in the slow green and red recording color forming layer units.

The layer structure (1) differs from the layer structure (2) in that a flat bleached grain blue recording color-forming layer unit is disposed between the green and red recording color-forming columnar layer units and the exposure radiation source. As already pointed out, the tabular grain W color recording chromogenic layer unit can be composed of It or more than one tabular grain W color recording green emulsion 4, and a plurality of back-to-back recording emulsion layers can be formed. If present, the sensitivity may differ. Layer structure (2) is different from layer structure (V) in order to compensate for the disadvantages suffered by the red recording color forming layer unit. A sensitive red recording color forming layer unit is arranged. Since this second tabular grain high-sensitivity red recording color-forming layer unit is placed in a favorable position, if the same emulsion is used in the two units, the sensitivity of the second high-sensitivity red recording layer unit is 1st. The sensitivity of the high-sensitivity red recording layer unit will be increased.

Of course, these first and second high speed tabular grain red recording color columnar units can be constructed of the same or different emulsions as desired and their relative sensitivities determined according to techniques well known in the photographic art. Can be adjusted. If desired, a second high-sensitivity red recording layer unit may be used instead of using two high-sensitivity red recording layer units as described above.

The 0-layer structure (■) in which the layer can be replaced with the second high-sensitivity green recording columnar layer unit may be the same as the layer structure (■), but the second
A high-sensitivity tabular grain red-recording color-forming columnar layer unit, and a second high-sensitivity tabular grain green-recording color-forming columnar layer unit are interposed between the exposing radiation source and the tabular grain red-color recording color-forming layer unit. They are different in that they are

Of course, the above-mentioned layer configurations 1 to 2 are merely examples, and there are many other advantageous layer configurations.

In each of the various layer configurations, the corresponding green and red recording color-forming columnar layer units can be rearranged, i.e., the sensitive red and green recording color-forming columnar layer units can be rearranged in the various layer configurations. Additionally or alternatively, the low-sensitivity green and red recording color columnar units can be relocated.

Multicolor #1t consisting of a combination of multiple subtractive primary color pigments
- The photographic emulsion to be formed takes the form of a polymerization of a plurality of layers incorporating dye-forming materials such as hyperchromic dye-forming materials, but this is not essential. Three color-forming components (commonly called lumenkets) are included in a photographic element, including a silver heronide emulsion to describe one-third of the visible spectrum and a subtractive complementary color coupler capable of forming primary dyes. Nine representative multicolor photographic elements that can be placed together in a single layer to form a multicolor photographic element are described in US Pat. No. 2,698,794 and US Pat. ,84
No. 3,489.

Tabular grain silver bromide is a green and red recording color-forming layer containing a silver bromoiodide emulsion, and the separation of blue and liner 11 color sensitivities is relatively large, eliminating or reducing the yellow filter material and ( or) it becomes possible to adopt a new layer configuration. One technique that makes it possible to quantitatively measure the relative responses of the green and red color-forming columnar units to color light in a multicolor photographic element is to first introduce a sample of a multicolor photographic element according to the invention through a tablet. Sexual exposure #
(i.e., light at 5500 am) and then process this sample to the 0th order and then expose a second sample in the same manner, except that only the intersecting light at 400 am and 490 am is transmitted. U, exposed without the intervention of a Ten98 filter,
Then process in the same way.

American Standard PH2,1-1 as mentioned above
Three dye characteristic curves can be plotted for each sample using nine colors, one transient for green and one for red, determined according to G.952. #Color recording color forming layer unit! The difference between the color sensitivity and the t color sensitivity of the red or red recording color forming layer unit can be determined from the following relational expression.

■ Δ= (BQl?8-Gwta) -(BN-G
*) is nine (B) Δ=(nwta-Rw9a)-(
BN-RN) In the above formula, 8w98 is the blue sensitivity of the t-color recording color-forming layer unit exposed through the Rabten 98 filter; Gwp6 is the blue sensitivity of the t-color recording color-forming layer unit exposed through the Rabten 98 filter; ri;Rwva
is mulberry at the t color sensitivity of the red recording color forming layer unit exposed through Rabten 98 filter; BN is neutral (550
RN is the green sensitivity of the green recording color-forming columnar layer unit that is exposed to neutral (5500'K) light; is the red sensitivity of the red recording color forming layer unit exposed to neutral (5500@K) light.

In the above description, blue, green and red densities have been expressed based on the blue, green and red recording chromogenic layers, ignoring undesirable spectral absorptions by yellow, magenta and cyan dyes.

Such undesired absorption is unlikely to be of sufficient magnitude to substantially influence the results obtained here for the purposes of the present invention.

Nine multicolor photographic elements employing emulsions according to the present invention can be fabricated to reduce the blue sensitivity of green and/or red recording color-forming layer units containing high aspect ratio tabular grain emulsions as described above without the presence of a yellow filter material. Both exhibit a blue sensitivity of 6 times, preferably at least 8 times, more preferably at least 10 times, due to the blue recording color forming layer unit.

Another technique for measuring the large separation in blue and minus blue sensitivities of multicolor photographic elements according to the invention is to compare the green sensitivity of a green recording chromogenic columnar layer unit or the red sensitivity of a red recording chromophoric layer unit to its blue sensitivity. That's true. The same exposure and processing techniques as above are used. however,
Neutral light exposure is replaced by negative blue light exposure by interposing a Kutten 9 filter that transmits only light exceeding 450 uni. Quantitative differences Δ" and Δ' are expressed by the following formula: % In the above formula, GW98 and Rw9B are the same as previously defined; Gv9 is the green sensitivity of the green recording color forming layer unit exposed through a Kutsuten 9 filter. and -1 is the red sensitivity of the red recording color forming layer unit exposed through a Kutten 9 filter. Again, undesired spectral absorption by the dye is not important and will be ignored.

The red and green recording color forming layer units containing tabular silver bromide or silver bromoiodide emulsions as described above are between the sensitivity in the blue region of the spectrum and the sensitivity in the portion of the spectrum to be spectrally sensitized (i.e. between blue and minus blue sensitivity). difference) of at least 10 times (1,OAogE), preferably at least 20 times (1,3AogE).

The quantitative relationships A:B and C:D in the same element will not result in the same results (except for the wavelength of spectral sensitization) even if the green and red recording color forming layer units are the same. This is because, in most cases, the red recording color forming layer unit has already passed through the corresponding green recording color forming layer unit and receives the next light. However, if a second element is provided that is identical to the first element except that the positions of the corresponding green and red recording color forming layer units are exchanged, then the red recording color forming layer of this second element The unit should exhibit substantially the same value for the relationship between B and D as the green recording color forming layer unit of the first element exhibits for the relationship between A and C.

Simply put, simply choosing green spectral sensitization as opposed to red spectral sensitization does not significantly affect the numbers obtained by the quantitative comparisons described above. Therefore,
Compare green and red sensitivities with blue sensitivities without distinguishing;
It is common practice to treat blue sensitivity and red sensitivity as relatively negative blue sensitivity.

F Reduced high-angle light scattering The high aspect ratio tabular grain emulsions of the present invention are superior to non-tabular grains and low aspect ratio tabular grain emulsions in that they exhibit reduced high-angle light scattering. It can be shown quantitatively. In FIG.
．． Although not shown in the drawings, the emulsion and support may be immersed in liquids having substantially matching refractive indices to minimize Fresnel reflections at the emulsion and support surfaces. desirable. The emulsion coating film is exposed by a parallel light source 5 from a direction perpendicular to the surface of the support. The light emanating from the light source passes through an optical path forming an optical axis, indicated by dotted line 7, and impinges on the emulsion coating at a point.

Light transmitted through the support and emulsion can be detected at a hemispherical sensing surface 9 placed at a distance from the emulsion. The maximum intensity level of light is detected at point B, which corresponds to the intersection of the first optical path extension and the sensing surface.

In FIG. 4, an arbitrarily chosen point C on the sensing surface is shown. The dotted line connecting AC makes an angle φ with the emulsion coating. By moving point C on the sensing surface, φ is reduced to O
It can be changed within the range of ~90°. By measuring the intensity of the scattered light as a function of the angle φ, it is possible to measure the cumulative light distribution as a function of the angle φ (because of the rotational symmetry of the light scattering around the optical axis 7). For a background description of cumulative light distribution, see Depa
lmm) and Gas A-(Ga5p@r), “Determining the Optical Gronogties
Ono Photographic Emulsion, 'N's Pies de Monte Cal Mouth Method', Photographic Emulsion
Science and Engineer, child y/s 1
Volume 6, Mu 3. May-June 1971, pp181-19
Please refer to 1.

Angle φ ranging from 0 to 90'' for emulsion 1 according to the invention
After measuring the cumulative light distribution as a function of , a conventional emulsion with the same average grain volume is coated with the same silver coverage on another part of the support 3 and the procedure described above is repeated. In comparing the cumulative light distribution as a function of the angle φ for these two emulsions, it is found that for values of φ up to 70° (in some cases up to 80° or more), the scattered light of the emulsion according to the invention is The amount of is small. In FIG. 4, the angle θ is shown as a complementary angle to the angle φ. The scattering angle line will be described here as an angle θ. Therefore, the high aspect ratio tabular grain emulsions of this invention exhibit much less high angle scattering. Since high angle light scattering severely reduces image sharpness, the high aspect ratio tabular grain emulsions of this invention can form images with excellent sharpness in either case.

The term “Collectio” used here
n) "Angle" means that half of the light impinging on the sensing surface lies within an area corresponding to the cone formed by the line AC rotating around the circumference of the polar axis with an angle of 0; Half of the hitting light refers to the value of the angle θ when hitting the detection surface within the area of the remaining beam.

While not wishing to be bound by reasoning to the property that the high aspect ratio tabular grain emulsions of this invention exhibit reduced high angle scattering, it is important to note that the large, flat primary crystals of the high aspect ratio tabular grains are It is believed that the orientation of the particles in the surface and in the coating contributes to the improvement of sharpness. It has been specifically observed that the tabular grains present in silver halide emulsion coatings are substantially aligned on the flat support surface on which they are formed. Light impinging on the emulsion layer from a direction perpendicular to the emulsion layer impinges substantially perpendicularly to one major crystal face of the tabular grains. The thinness of the tabular grains, combined with their orientation during coating, results in the high aspect ratio tabular grain emulsion layers of this invention being substantially thinner than conventional emulsion coatings, resulting in reduced sharpness. improves. However, the emulsion layer according to the present invention exhibits excellent sharpness even when coated to the same thickness as a conventional emulsion layer.

In particularly preferred forms of the invention, the high aspect ratio tabular grain emulsion layer is at least 1.0 micrometers;
More preferably it exhibits a minimum average particle diameter of at least 2 micrometers. Increasing the average particle diameter improves both sensitivity and sharpness. Although the maximum average grain diameter that is useful will vary depending on the graininess tolerated by the particular imaging application, the maximum average grain diameter of high aspect ratio tabular grain emulsions according to the present invention can be any In some cases it is less than 30 micrometers, preferably less than 15 micrometers, more preferably less than 10 micrometers.

Although the single layer coating of the high aspect ratio tabular grain emulsion according to the present invention can reduce high angle scattering,
Reduction of high angle scattering is not necessarily achieved with spectacular results in multicolored coatings. Although improved sharpness is achieved in certain multicolor coating configurations using the high aspect ratio tabular grain emulsions of the present invention, in other multicolor coating configurations, the high aspect ratio tabular grain emulsions of the present invention Grain emulsions can actually reduce the sharpness of the underlying emulsion layer.

Layer structure! Returning to , the blue recording emulsion layer is located closest to the exposing radiation source, while the underlying green recording emulsion layer is comprised of a tabular grain emulsion according to the present invention.

Additionally, a green recording emulsion layer is disposed over the red recording emulsion layer. As in many nontabular emulsions,
Unfortunately, if the green recording emulsion layer were to incorporate grains with an average diameter of 0.2 to 0.6 micrometers, there would be maximum scattering of light passing through it to the green and red recording emulsion layers. However, if the light is already scattered before it reaches the high aspect ratio tabular grain emulsion that forms the green recording emulsion layer, then the tabular grains allow light to pass through it to the red recording emulsion layer more easily than in conventional emulsions. It can be scattered much more. Therefore, this particular emulsion and layer configuration selection results in a greater reduction in the sharpness of the red recording emulsion layer compared to a layer configuration without emulsion according to the invention.

The emulsion layer underlying the high aspect ratio tabular grain emulsion layer according to the invention is designed to receive substantially unscattered (preferably specularly transmitted) light in order to achieve the sharpness object of the invention. In other words, to achieve the best sharpness in the emulsion layer located below the tabular grain emulsion in the photographic elements of this invention, it is desirable to locate the tabular grain emulsion layer in the photographic elements of this invention. Only if the layer itself is not located below the turbid layer. For example, a high aspic ground tabular grain green recording emulsion layer is disposed above a red recording emulsion layer and below a Rigman emulsion layer and/or a high aspic ground tabular grain blue recording emulsion layer according to the present invention. If the sharpness of the red recording emulsion layer is
19 may be improved by the presence of two or more tabular grain emulsion layers.

Quantitatively speaking, it is the collection of two or more layers on a high aspect ratio tabular grain green recording emulsion layer.

If the angle is less than about 10', the sharpness of the red recording emulsion layer is improved. Of course, as a limitation regarding the effect of the overlying layer on sharpness, it is not critical that the red recording emulsion layer itself be a high aspect ratio tabular grain emulsion layer according to the present invention.

In multicolor photographic elements formed by polymerizing multiple color-forming units, the emulsion layer closest to the exposing radiation source is comprised of at least a high aspect ratio tabular grain emulsion to achieve the sharpness benefits aimed at by the present invention. It is desirable to do so. In a particularly preferred form of the invention, each emulsion layer located closer to the exposing radiation source than the other deposited recording emulsion layers is comprised of a high aspect ratio tabular grain emulsion. The layer structure mentioned above ■
.

2, v, vt, and 2 represent layer arrangements of multicolor photographic elements according to the present invention that can significantly improve the sharpness of the underlying emulsion layers.

Although the superior contribution of high aspect ratio tabular grain emulsions to image sharpness in multicolor photographic elements has been discussed in detail with reference to multicolor photographic elements, the advantages for sharpness of multilayer emulsions intended to form silver It is also recognized in black and white photographic elements. It is a common technique to separate emulsions that form black-and-white images into fast and slow layers. The use of the high aspect ratio tabular grain emulsions of this invention in layers close to the exposing radiation source improves the sharpness of the underlying emulsion layers.

(4) Aspects The present invention will be explained in more detail with the following examples. In each instance, the reaction vessel contents were vigorously agitated throughout the introduction of the silver and chloride salts.

The term "/g-cent" means % by weight unless otherwise specified, and the term "rMJ" means molar concentration unless otherwise specified. ing. All solutions are aqueous solutions, except in cases where there is a break.In the case where the non-use is specifically stated for calculating the average diameter and projected area (ch) of tabular grains in the emulsion, all solutions are aqueous solutions. Although tabular grains (diameters less than O, S micron) were included, there were tabular grains with insufficient small diameters to significantly change the reported values. Comparative Example 1: This example describes the nonselective epitaxial growth of silver chloride on a tabular grain AgBrI emulsion containing 6 moles of iodide and not previously spectrally sensitized.

Emulsion IA Tabular AgBrI host grains (6 mol qb iodide) 0.
6.0 μl of a 1.5% gelatin solution at 55° C. containing 12 M potassium bromide was added with stirring and by the double jet method to 2.0 μl containing 0.12 mol of KI.
8 molar KBr solution and 2.0 molar AgNOs solution
0.92 pB during the addition period.
r was maintained (consumed 5.3s of the total amount of silver nitrate used)
. The subbromide and silver salt solutions described above were then added simultaneously to p
Addition over 41 minutes at an accelerated flow rate (6.0× from start to finish, i.e. the flow rate at the end is 6.0 times greater than that at the start) while maintaining Br −0.92 (94.7% of the total amount of silver nitrate used)
).

A total of 3.0 moles of silver were used. The emulsion was cooled to 35°C, washed by the coagulation method described in US Pat. No. 2,614,929, and measured at 40°C to give pAg = 7.
The resulting tabular grain AgBrI (iodide 6 mol's) emulsion had an average grain diameter of 3.0 μm, an average thickness of 0.09 μm, and an average aspect ratio of 33:1. .851 of the particles were tabular based on the projected area.

Emulsion IB Epitaxial growth of AgCj on the main crystal planes of host grains Tabular grain AgBrI emulsion I prepared as above
A 0.1 mol AgNO3 solution was added to 40 g of A (0.04 mol) to adjust the pAg at 40C to 7.2.
1. A 0.79 molar NaCt solution of OEj was added.

Then 0.54 mol of NaCL and O,S mol of AgNO3 were added while keeping the pAg at 7.5 at 40°C.
The solution was added over a period of 8.3 minutes.

AgC2 in an amount of 5 moles of the total amount of silver halide was obtained as a deposit by epitaxial growth. For simplicity,
This emulsion is referred to as the 5M Lskgct emulsion, and similar nomenclature applies to the following emulsions.

FIG. 5 is a 7 replica electron micrograph of the emulsion. This photograph shows that silver chloride was deposited on the main crystal faces. The deposits formed are generally more or less random on the main crystal faces, although for some grains epitaxy appears to predominate near the edges of the main crystal faces. Note that no spectral sensitization of the AgBr1 (6 moles iodide S) host emulsion was performed prior to the addition of silver chloride.

Below is a margin LLr In this example, grain processing of a spectrally sensitized tabular grain AgBr emulsion and deposition of AgCA along the margin will be described.

mshiL Tabular AgBr host particles 1 at 80°C containing 0.073 mol of sodium bromide
．． 5 To 2.01 of the tisgelatin solution, while stirring it and by double jet method, 0.30 molar NaBr solution and 0.05 molar AgNO3 solution were added over 5 minutes; OpBr was maintained (0.4- of the total usage of glass was consumed). Then,
The bromide and silver salt solutions described above were added at the same time, pBr=1
．． 14 was added over 4 minutes at an accelerated flow rate (3, OX from start to finish) while maintaining nitrate II.
Consumes 0.66Is of l silver usage) 0 then 1.5
mol of NaBrjll solution and 1.5 mol of AgNO3
The solution was added over 25 minutes (consuming 66.21 of the silver nitrate usage) at an accelerated flow rate (143× from start to finish) while maintaining pBr −1.14.

The acceleration was then stopped and the solution was added at a constant flow rate over 6.6 minutes (consuming 32.81 of the silver nitrate usage), for a total of about 3.03 moles of silver salt used. The emulsion was cooled to 40° C. and the emulsion was cooled to 40° C.
and stored at pAg = 8.0 measured at 40°C.

The tabular grain AgBr emulsion obtained had an average grain diameter of 5.0 μm and an average thickness of 0.09 μm.
The average aspect ratio is 56:1 and, based on the total projected area, 85% of the grains are tabular.

Emulsion 2B Epitaxial Growth of AgCt on the Major Crystal Faces of the Host Grains The 9 μgBr host grain emulsion prepared as described above was spun down and resuspended in L85×10 −2 molar 11 NaCj solution. 2.5 moles of muggc
4 was added to a 40JF emulsion (0.04 mol) with 0.55 mol of N while maintaining the pAg at 40°C at 7.5.
Precipitation was carried out by double jet addition of aCA and 0.50 molar AgNO3 solution over 4.1 minutes. This emulsion was mixed with Ag 1 mol ml. The dye, anhydro-5-chloro-9-ethyl-5'-phenyl, L3'-es(3-sulfopropyl)oxacal, was spectrally sensitized with cyanine hydroxide, triethyl acetate #1.

Emulsion 2C Selective epitaxial growth of AgCj in Example 1 This emulsion was prepared according to the same procedure as described in Graph B above. However, in the case of this emulsion, NaCL
Spectral sensitization was performed with 1.0 mmol of Dye A (per mole of Ag) prior to addition of the solution of and AgNO3.

Spectral sensitization was performed after the addition of AgCL, and in the case of Emulsion 2B, iCAgCA was randomly attached to the crystal surface (see Figure 6). *Spectral sensitization was performed prior to the addition of AgCL. In the case of Emulsion 2C, most of the AgCj was deposited exclusively along the edges of the grains (see Figure 7). Generally, the few small grains present (shown as resting on the major crystal faces of the tabular grains) are not attached to the tabular grains by epitaxial growth, but are independent grains.

Emulsions 2B and 2C were prepared with silver 1,61 on a 4-reproduced support.
The gelatin was coated at a coverage of 3.583 mm. 0.54 ? on this emulsion layer. /d gelatin layer was applied. The emulsion coating film has a density of θ~6.0.

!・Tabley y) (0,30 steps f) t-600
Exposure to a tungsten light source at 2850@W for l/10 seconds and 20°C ON-methyl-p-ha,7
87-kat□7! -) (t...1) - Processed in a time development system with a hydroquinone developer for 1 to 20 minutes. The obtained sensitometric measurement results are listed in the table below.

Control 2B Random 235 0.1
0 Example 2C Engineering, Di 315 0.10 Example 3: This example describes the epitaxial growth of hgct at the corners of a tabular host crystal that is not spectrally sensitized.

Control Emulsion 3A Random epitaxial growth of AgCA on the main crystal planes of host grains Tabular host grains A described in Example 2, Paragraph A above
gBr emulsion 2A was centrifuged and 1.85 x 1
The 40P host emulsion (0.04 mol) was resuspended in a 0-''M NaCt solution.
while maintaining the pAg at 7.5 at 40°C.
．． Precipitated by double jet addition of 55 M NaCA and 0.5 M AgNO3 solution over 4.1 min, this emulsion was then precipitated with 1 mol Ag, bi, o mmol dye. Spectrally sensitized.

Emulsion 3B Selective epitaxial growth of MugCt on host grain corners 400 j' OAgBr host grain Emulsion 2M (0,4
0.5 molar of iodide (mol) was added by pouring a 4.0 x 10 molar Kl solution at 5.0114/min over 10 minutes. The emulsion was centrifuged and resuspended in 1.85 x 10 molar NaCj solution, then 2.5 molar AgCl was added to 40
0.55 mol of NaCA in the host emulsion (0.04 mol) of
The emulsion was then spectrally sensitized with 1.0 mmol of dye (per mole of Ag).

Control emulsion 3C Iodide-added control grains containing no AgCA Emulsion 3B
Emulsion 3C was prepared and spectrally sensitized following the same procedure. However, in this emulsion, epitaxial growth of AgCt was omitted.

In the case of Emulsion 3, which was spectrally sensitized after addition of AgCj, hgct was randomly deposited on the entire main crystal plane (see FIG. 8). 0.0 prior to the addition of AgCt.
In the case of emulsion 3B with 5 mol of KI added, most of the hgct was attached exclusively to the corners of the grains (9th
(see figure), the small particles resting on the main crystal planes were grown independently and were not allowed to grow epitaxially on the main crystal planes.

Emulsions 3A, 3B and 3C were coated as described in Example 2 above, exposed and processed in the ** system for hours. The obtained nine-sensitometric measurement results are listed in Table 2 below.

3 A AgC//AgBr Random 240 0.153B AgCA/(AgBr
+I-) Corner 326 0.153CA
gBr-)-I″″ None 2
45 0.15 Example 4: This example illustrates the epitaxial deposition of the bulk of MugCt exclusively at the corners of a spectrally sensitized tabular grain MugBr emulsion.

Emulsion 4 tabular AgBr host grains containing 0.067 moles of sodium bromide at 80°C.
．． 5th attack gelatin solution 3.0! Then, while stirring, 0.1 mol of Na11 was added by the Daturje method.
r solution and 0.1 molar AgNO3 solution were added over 3.75 minutes, during which time a pBr of 1.17 was maintained (consuming 0.22 g of total silver nitrate usage).
Then, 3.0M Na1ir solution and 3.0M AgNO3 solution were simultaneously introduced at an accelerated flow rate (24.8X from start to finish) while maintaining pBr=1.17.
(consumed 91.0% of the total amount of silver nitrate used) over a period of 31 minutes. The addition of the NaBr solution was stopped and the addition of the AgNO5 solution was continued until a pAg of 7.75 was achieved (consuming 6.8% of the total silver nitrate usage). A total of about 6.85 moles of silver nitrate were used. The emulsion was cooled to 40° C., as described in U.S. Pat.
(according to the coagulation method described in this issue) and stored at pAg = 8.5 measured at 40°C. The resulting tabular grain AgBr emulsion has tabular grains with an average grain diameter of 2.
9μm5 average thickness 0.11μm1 average aspect ratio 26:1. Then, based on the total projected area, 9 of the particles
Emulsion 4B in which 691 was tabular Epitaxial growth of AgCL on the corners of host grains Tabular grain AgBr host emulsion 4A (0°04 mol) 4 (0.1 mol of AgN in l) v4m as described above
pAg 1 to 7.2 at 40 °C by adding 0.5 solution
It was adjusted to This emulsion was mixed with 1.6 mmol Ag, 1 mol Dye B, 1. Spectrally sensitized with l'-diethyl-2,2'-cyanine p-toluefsulfonate and stirred at 40°C for 5 minutes. Then 1.0 mg of 0.5 molar NaC4 solution was added. Then 5.0 mol-01
gC1 in host grain emulsion, PAl at 4.0°C
Precipitation was carried out by double jet addition of 0.52 molar NaCA and 0.5 molar AgNO3 solution over 8 minutes while maintaining r at 7.2.

FIG. 1O is a Kagen Replica electron micrograph of the grains of an AgCl-gBr epitaxially grown emulsion.

Example 5: This example describes selective epitaxial corner growth K'' of hgct on tabular grain AgB r I emulsions.

Emulsion 5A Tabular AgBrI (6 moles of iodide) host grains 0.
1.51 gelatin solution at 55°C containing 12 moles of beautifying potassium 6.0! 1, containing 0.06 mol of KI, was mixed with stirring and by the double jet method.
A 12M KBr solution and a 1.0M 4g NOs solution were added over 8 minutes (5% of the total Nit #1 silver usage).
,0chi consumed). At the same time, the temperature was increased to 70° C. for 7 minutes. Then, 0.12 mole of KI is stored2
, 0 molar KBr solution and 2.0 molar AgNO3 solution were added simultaneously over 30 min at an accelerated flow rate (4.OX from start to finish) while maintaining pBr = 0.92 at 70 °C. In total, approximately 3.16 moles of silver salt were used (consuming 95.0% of the total amount of silver used). The emulsion was cooled to 35° C. and the emulsion was cooled to 35° C.
The resulting tabular grain AgBr1 (6 moles iodide) emulsion was washed by the coagulation method described in The average particle diameter is 2.7 Jim and the average thickness is 0.
The average aspect ratio was 34:1, and 85% of the grains were tabular, based on the total projected area.

Emulsion 5B Selective epitaxial growth of AgCA on the corners of host grains Tabular grain AgBr1 prepared as above Host emulsion 5A (0.04 mol) 0.1 mol of AgN in 40f
The pJkl at 40°C was adjusted to 7.2 by adding O3 solution *1. A 0.54 molar NaC6 solution of Qd was added. This emulsion was spectrally sensitized with 71 g of 1.0 mmol of dye and then 5.0 mole of OAgCj was added to the host tabular grain emulsion with a pAg of 7.0 mm at 40°C.
0.54 mol NaCA and 0.50 mol while holding at 5
Precipitation was carried out by double jet addition of molar AgNO3 solution over 7.8 minutes.

FIG. 111 and FIG. 11b respectively show 2 of emulsion 5B.
This is the next electron micrograph. These photographs show 5.0 moles of AgCA epitaxially deposited at the corners of a tabular Mu gBrI (6 moles of iodide) crystal.

Example 6: This example describes selective epitaxial growth corner deposition of AgBr on a spectrally sensitized tabular grain AgBr1 emulsion.

Emulsion 6 μm tabular AgBr1 (12 moles qb iodide) host grains 1.5 at 55°C containing 0.14 moles potassium bromide
% gelatin solution 9.0! 2. while stirring it.
A 0M AgNO3 solution was added over 15 seconds (consuming 0.41 of the total silver nitrate usage).

A 2.05 molar KBr solution containing 0.24-% Kl and a 2.0 molar KBr solution were then added by double jet addition method.
molar AgNO3 solution was added over 15 seconds (
(consumed 0.44 of the total amount of silver nitrate used).

The norodanide and silver nitrate solutions described above were then added simultaneously over a period of 7.5 minutes (consuming 2.3 hours of the total interdose of silver nitrate) while maintaining pBr = 0.92. Next, the above halide and silver nitrate solutions were simultaneously added while maintaining pBr = 0.92.
Added over 41 minutes at accelerated flow rate (6.6X from start to finish) (96.9 of total silver nitrate usage)
1), the emulsion was cooled to 35° C. and the emulsion was cooled to 35° C. and the emulsion was cooled to 35° C.
614,929 and measured at 40°C to determine pAg! Saved in 8.2. The resulting tabular grain AgBr1 (iodide 12 moles ts) emulsion had an average grain diameter of 2.14 m, an average thickness of 0.10 μm, an average asquid ratio of 21:1,
Based on the total projected area, 75- of the particles were tabular.

Emulsion 6B Selective epitaxial growth of AgBr on corners of host grains Tabular grain AgBr1 (12 moles of iodide) prepared by K as described above Host grain emulsion 6A (0.06 moles) 5
Add 0.2 mol AgNO3 solution to 6.8P and heat at 40℃
The pAg was adjusted to 7.6. This emulsion is 1.5
spectrally sensitized with mmol/mol of Ag, and
Na28203 was then added into a 4.2 mol-AgBr t host tabular grain emulsion held at 0°C for 5 minutes while holding the pag at 7.2 at 40°C.
・5H20 (20,8W/j) and KAuCA4 (20
, 8rtv/j) and 0.2 mol of NaBr containing
Precipitation was performed by double jet addition of solution g and 0.2M AgNO3 solution over 12.8 minutes.

The emulsion was heated to 60°C and held for 10 minutes.

Chemically sensitized tabular grains AgBr prepared as above
/AgBrI emulsion 6B on a cellulose ester support *1.07 t~ and gelatin 2.15 t/d coated with 600W 3000@D from a tungsten light source! An n□ exposure was given for 1P 100 seconds and then processed for 75 seconds at 20° C. in the Liwei liquid described below.

Current Salary Solution A Hydroquinone 10.0PNa2SO51
0,Of Sodium Metaborate 10.0? Add distilled water to total volume 1. Oj...=9,4 After development, the coating was immersed in an acetic acid stop bath for 1 minute and then washed with distilled water.

FIG. 12 is a gelatin capsule electron micrograph of partially developed particles. In this photo, the blackest part has been developed to represent the round steel. From the position of the developed silver,
It can be seen that most of the formation of latent cavities occurs exclusively at or near the corners of tabular grains.

Margin below Example 7: This example describes the sensitivity and minimum density as a function of epitaxy for both new and preserved samples. This example also describes the location of infiltration formation by inspection of partial 3J* completed particles.

Emulsion 7A Chemically and spectrally sensitized 9 mgBrl (6 moles of iodide)
Host Grain Emulsion IA Tabular MugBrI (6 moles iodide) Host Grain Emulsion IA 5 W/A g 1 mole Na2820s@5
Chemical sensitization was carried out using KAu CL4 at 20 and 5 Da/1 mole of Al at 60° C. for 10 minutes, and then spectrally sensitized using Dye A at 1.5 mmol/1 mole of Ax. This emulsion was applied onto a 4-reproduced support.
A coverage of 611 Pm'' and 3.589 Pm'' of gelatin was applied. This emulsion layer KO was overcoated with a 54 g thick layer.゛Emulsion 7B Spectrally sensitized epitaxial growth AgC4/Ag1lr
I Milk 1 Tabular AgBrI (6 moles of iodide) host grain emulsion I
A (0.04 mol) and 0.1 mol of AgN0. and 0,
40°C by simultaneously adding 006 mol of KI.
Adjust the pAg to 7.2 and then 1.01
of 0.80 molar NaCj solution was added. This emulsion was spectrally sensitized with 1.5 mmol/mol of Ag dye.

1.25 mol of AgCt was then added to the host tabular grain emulsion with 0.54 mol of NaCA and 0.50 mol of AfNO while maintaining the pag at 40°C at 7.5.
, the solution was precipitated by double jet addition over a period of 2 minutes.

Emulsion 7C Chemically and spectrally sensitized Evita Φdiyl grown AgC1/A
gBrI emulsion tabular AgBrI (6 mol iodide l host grain emulsion I
A contains 0.1 mol of AgN0. and 0.006 mol KI
pAg at 40°C by simultaneously adding
Adjusted to t 7.2. A 1.0-0.74 molar NaCL solution was then added. The emulsion was spectrally sensitized with a color mA of 1.5 mmol/mol Ag and at 40°C.
It was held for 0 minutes. The emulsion was centrifuged and resuspended twice in 1.85XIO Molar NaCj solution. Then 1.25 momoles of Aget
in a tabular grain host emulsion of 409 (0.04 mol) while maintaining the PAg at 40°C at 7.5.
Precipitation was carried out by double jet addition of a 4M NaCA and 0.50M AgNOs solution over 2.1 minutes. Add this emulsion to 0.5111VIA
g 1 mol Na2820.・5H20 and 0.5~/
Chemical sensitization was performed with 1 mol of At KAuC64.

The chemical sensitizer was added 15 seconds after starting the addition of NaCl, MugNo, and reagents. Figure 13 is an electron micrograph of this emulsion showing selective epitaxy at the corners.

Emulsion 7D Chemically and spectrally sensitized epitaxially grown AgCt/A
gBrI emulsion.

Emulsion 7D was prepared in the same manner as Emulsion 7C.

However, in the case of this emulsion, the emulsion was mixed with 1.01111f/Ag 1 mol of KAuCj4 and 1.01111f/Ag 1 mol KAuCj4 and 1. Qq/Ag 1 mol Na28203' 5
Chemical sensitization was performed with H2O.

The emulsion described above was coated, exposed and processed in a time development system as described in Example 2 above. The sensitometric measurement results are listed in Table y below.

Table y Emulsion Log sensitivity 1-carrier F A
I93 0.107B
311 0.107 C
3430,10 7D 346 0.
I O” 30 ” O-3log Ke E in the formula
is the exposure amount (meters-cantreux seconds).

As is clear from Table 1 above, spectrally sensitized epitaxially grown AgCA/AgBrI tabular grain emulsion 7
B, 7C and 7D are chemically and spectrally sensitized nine host particles AgBr with or without chemical sensitization added to it.
Significantly higher sensitivity (-1,2log E
). Furthermore, significantly less chemical sensitizer was used in Emulsions 7C and 7D than in Emulsion 7A.

In addition, the Ia[c of emulsions 7A and 7C was kept at 49°C and 50% relative humidity (R0H6) for one week and a step tablet of 1lfO to 6.0 (0,30
N-Methyl-p-aminophenol sulfate) (M
The film was treated with @tol■-hydroquinone developer for 6 minutes. Sensitometric measurements showed that epitaxially grown Ag Ct/AgBrI emulsion 7C was more sensitive and produced less capri than host grain AgBrI emulsion 7A. Please refer to Table 7.

Table V 7A 225 0.227
0 336 0°09 Studies on Inhibited Development Tabular grain AgBrI (6 moles iodide) emulsion 7A and epitaxial growth^gcj/AgBrI emulsion 7C on a cellulose ester support with silver 1.61! i/m”
The resulting emulsion layer was overcoated with a 0.54 flow gelatin layer.

Glue emulsion 7A coating from a tungsten light source at 600W and 2850°. ,! The exposure is given for 1/10 second,
Then, it was processed in the following developer B1 at 20° C. for 50 seconds. Emulsion 7C coating film Nomaku 600W285
Dm &

Developer B Hyde non-filling 0.4g
1iton (N-methyl-p-aminophenol sulfate)) 0.2Ji
lNm, 80s2.0 j' KBr
0.51i sodium metaborate 5.
Add OIi distilled water, total volume 1.0L
pH=10.0 Current**, the coating was immersed in a 5-thiacetic acid stop bath for 30 seconds and then washed with distilled water for 2 minutes.

FIG. 3 is a gelatin capsule electron micrograph of partially developed emulsion 7A grains. The location of the developed silver (blackest area) indicates that the formation of the IIF image occurred primarily randomly along the edges of the tabular grains. Shown in Figure 2 is a partially developed emulsion 7C (0 grains). From this Figure 2 it can be seen that most of the latent image formation occurred exclusively near the corners of the tabular grains. It turns out that.

Example 8: In this example, tabular grain epitaxial growth Ag(4/
The photographic response of the AgBrI emulsion is illustrated with respect to spectral sensitization before the deposition of AgCA and after the deposition of s-AgcA.

Emulsion 8A Selective epitaxial growth of AgCt on the corners of host grains (spectral sensitization was performed prior to silver chloride precipitation) Tabular AgBrI (6 moles iodide Is) host grain emulsion IA
and 0.10 mol of AgN0. and 0.006 mol KI
Solution I was added at the same time to adjust the pAg at 40°C to 7.2. 1.0 WLl of 0.74 molar NaCt solution was added. The emulsion was spectrally sensitized with 1.5 mmol/Ag 1 mole of color chart A and held at 40 °C for 30 min. The emulsion was then centrifuged and
．． 85
Cj in a tabular host emulsion, PAlg at 40°C
0.54 mol NaCA and 0 while holding at 7.5
．． 50 moles of AgN0. Precipitation was carried out by double jet addition of Solution II over 2 minutes.

15 seconds after start of addition of NaCL and MugNO, reagents, 0
．． 5ψN1□S20.・5H2Φ/Ag1 mol and 0.
5 Da KAu CL4/'Ag 1 mole was added.

Emulsion 8B Emulsion 8B was prepared by random epitaxial growth of hgct on the major faces of the host grains (spectral sensitization was performed after silver chloride precipitation).
It was prepared according to the same procedure as Emulsion 8A. However, in the case of this emulsion, HGCT deposition was followed by spectral sensitization with a dye concentration of 1.5 mmol/Ag1 mole.

Emulsion 8A subjected to spectral sensitization prior to the addition of kgcL
From the electron micrograph of Ag (A is exclusively tabular AgBr)
It was found that it was deposited near the corners of the I crystal. However, in the case of emulsion 8B (where spectral sensitization was performed following AgCA deposition), AgCt is the subject J
It was found that the emulsions 8A and 8Bt were deposited randomly on the 8A and 8Bt cellulose triacetate supports.
It was coated at a coverage of 6°011/m" and gelatin 3.589/*- and exposed and processed in a development system for a time similar to that described in Example 2 above. From the sensitometric measurements, At equal Dmin (0,10), emulsion 8A was found to be 0.701 ogE more sensitive than emulsion 8B.

Example 9: This example describes the photographic response of a tabular AgCA/AgBrI emulsion with spectral sensitization performed prior to the addition of AgCA.

Emulsion 9A Selective epitaxial growth of AgCA on the corners of host grains 40 g of tabular AgBrI (6 moles of iodide) host grains emulsion IA with 0.10 moles of AgN0. and 0.00
6 mol of KI was added simultaneously to reduce the pAg at 40°C to 7.
．． Adjusted to 2. Then 1.01 of 0.8M NaCl
solution was added. This emulsion was mixed with cyanine hydroxide and triethylamino salt at 1.8 mmol/1 mol of Ag. Spectrally sensitized and held at 40°C for 30 minutes. Then 1.25 mole of AgC6 was added to the tabular grain host emulsion with 0.54 mole of NaCt and 0.50 mole of AgN while maintaining the pAg at 40°C at 7.5.
0. Precipitation was carried out by double-jet addition of the @ solution over a period of 2 minutes.

Emulsion 9B AgCA (DAu sensitized selective ebitaxyl growth on the corners of the host grains) Emulsion 9B was prepared following the same procedure as emulsion 9A above, except that for this emulsion, NaC1 and AgN0. , 11 moles of hBo47A of 1.0~ were added.

Emulsion 9C Sulfur sensitized selective epitaxylic growth of AgCt on the corners of the host grains Emulsion 9C was prepared following the same procedure as Emulsion 9A above. However, in the case of this emulsion, 1.0111p of Na2820 was added 15 seconds after the start of addition of NaCL and AgNO3 reagents.
1 mole of 3'5 H,O/Ag was added. Furthermore, after the formation of the precipitate was completed, heating was performed on Emulsion 1i-60p for 10 minutes.

Emulsion 9D AgCA O selenium on the corners of host grains (
S.) Sensitized selective epitaxial growth emulsion 9D was prepared according to the same procedure as emulsion 9A. However, in the case of this emulsion, khcL and AgN0. After starting the addition of reagents,
15 seconds, 0.17 ~ sodium selenite (NazS
@Os)/Ag 1 mol was added.

$1JIJ9A-9Di cellulose triacetate film support was coated at a coverage of 1.15 c. silver and 3.51 m/m'' gelatin. In addition, 1.871 mg/mole of tabular AgBrI host grain emulsion IA was coated on a JIJ9A-9Di cellulose triacetate film support. The tabular grain AgBrI host emulsion was first coated with 5 Da KAuCA7Ag and coated as described above.
1 mol + 51q/ Na 2s 201' 5
Chemically sensitized with 1 mole of HzO/Ag at 60° C. for 10 minutes and then spectrally sensitized with 1 mole of 1.8711 M1//Ag of Dye C and coated as above. These coatings were exposed to a 600W 5500"K tungsten light source for VIO seconds through a delayed wedge tablet from 0 to 4.0, and then exposed to N-methyl-
p-aminophenol sulfate (Metal■)-
Processed in hydroquinone developer at 20°C for 6 minutes. From the sensitometric measurement results, epitaxy
AgCtAgBrI emulsions 9A to 9D are spectrally sensitized.
Significantly higher sensitivity (>2.01og) than gBr4 host grain emulsions (with and without chemical sensitization)
E) is υ and higher. .

It turns out that it has Please refer to Table ■ below.

Example 1O: This example describes the epitaxial growth of AgBr at the corners of a spectrally sensitized tabular AgBr I crystal.

Emulsion 10A Tabular AgBrI (6 moles iodide) Selective epitaxial growth of AgBr on the corners of host grains Tabular AgBrI (6 moles iodide 9G) Host emulsion I
A was spectrally sensitized with 1.5 mmol/1 mole of Ag dye A. Following spectral sensitization, the emulsion was centrifuged and suspended twice in distilled water.

Then, 0.6M AgBr was spectral sensitized with 409 A.
gBrI host grain emulsion (0.04 mol) at 40°C.
0.2 mol N while keeping the pAg at 7.5
aBr and 0.2 mol of AgN0. The solution was precipitated by double jet addition over 1.5 minutes. Naar and AgN0. Start adding reagent [15 seconds #
1.01v(2) Ni2820.・5 H20/A
g 1 moA, and 1.0 da KAuCLa/A g
1 mol was added. Ebitaxil growth AgBr/Ag
See Figure 14 for a cardan replica electron micrograph of the BrI emulsion.

4. Tabular AgBrI host grain emulsion IA. KAuCA of OM9, /Ag 1 mol and 5.0 mol Na2S2
0. Chemically sensitized with 5H20/1 mol of Ag for 10 min at 60°C and then with 1.5 mmol/Ag
Spectrally sensitized with 1 mole of dye A. Host grain emulsion IA and epitaxially grown AgBr/AgBr1 emulsion were coated, exposed, and processed as described in Example 2 above.

From the sensitometric measurement results, epitaxial growth emulsion 1 was sensitized at low temperature using a significantly small amount of chemical sensitizer.
0A is approximately 0.801o compared to sensitized AgBrI host grain emulsion IA at equal Dmln (o, t o ).
It can be seen that only gE has high sensitivity.

Below is the margin - Φ Φ φ - Example 11: In this example, the tabular AgB sensitized with a supersensitizing dye conjugate
Ebitaxyl growth of AgCA on r-grain emulsions will be described.

Emulsion 11A This emulsion was used as the tabular AgBv host grain emulsion 2 of Example 2.
It was prepared in the same way as humans. The resulting emulsion had an average grain diameter of 3.9 k+% and an average grain thickness of 0.09 μm. Thickness less than 0.3 micrometer and moth low 0
．． The grains with a diameter of 6 micrometers exhibited an average aspect ratio of 43:1 and occupied 90 Ft of the total projected area of the silver bromide grains on the host grain corners of the emulsion spectrally sensitized with emulsion 11B dye conjugates. AgC4/AgBr Oim selective epitaxy in 1
AgBr host grain emulsion 11A (0,
04 mol) to 0.1 mol of AgN0. Add solution for 40 minutes
The pAg at °C was adjusted to 7.20 then 1.0
1 of 0.61 mol NaCLi! 1 solution was added. This emulsion was spectrally sensitized with Dye B at 1.5 mmol/mol of Ag.

1.25 moles of Aget in the host tabular grain emulsion while maintaining the pAg at 40°C of 7.5.
By double jet addition of 4M NaCA and 0.50M AgNOs solution over 2 minutes.
precipitated.

Sensitometric measurement results Paint film 1: Flat kgB? Host grain emulsion 11A was spectrally sensitized with 1.5 mmol/mol of Ag and 0.15 mmol/mol of Ag of dye B, and then the polyester Silver 1.73,9Δ- and gelatin 3.
A coverage of 58 seams was applied. 0.541 in this emulsion layer
1/>- gelatin was coated with O74.

Coating film 2: Tabular AgBr host grain emulsion 11At-1,5111
fKAu CL 4/'A g 1 mol + 1.511 g
Na2S20. -5H20/Ag1 mole at 65℃
It was chemically sensitized in a minute. This emulsion was then spectrally sensitized and coated as described for Coating I above.

Coating 3: Tabular grain ebitaxyl grown AgC4/AgBr emulsion] IB spectrally sensitized with Dye B, followed by silver chloride deposition, further sensitized with 0.15 mmol/Ag1 mol of dye; It was then coated as described for Coating 1 above.

The resulting m-film was exposed as described in Example 2 above and processed in a time development system. The obtained sensitometric measurement results are shown in Table 1 below.

Margin below As can be seen from the above, the epitaxially grown AgCA/AgBr emulsion 11B, which was spectrally sensitized prior to the deposition of AgBr, has a 1.
It was highly sensitive by 31 log sensitivity units.

In addition, this emulsion 11B was chemically sensitized and then physically sensitized to 631 o
The sensitivity was high by g sensitivity units.

Example 12: In this example, fine grain kgc is added to the tabular grain AgBr1 emulsion.
VjA was made by adding L emulsion, and the epitaphΦ
The silage-grown AgC4/AgBrI emulsion will be explained.

Emulsion 12A Fine grain Aget emulsion 3.4X, 3.3% containing 10 moles of N-Ct.
Gelatin solution 3. A 4.0 molar sodium chloride solution and a 4.0 molar silver nitrate solution were added to the solution over 0.4 minutes at 9, pAg = 6.9, while stirring it and by the double jet method. Next. A 0.24 molar hgct emulsion was obtained.

Emulsion 12B Epitaxially grown AgC2/AgBrI emulsion 309 tabular grains AgBr I containing 2.5 moles of Aget (6 moles of iodide, spectrally sensitized with Dye A at 1.1 mmol/1 mole of Ag) , and held at 40°C for 15 minutes. Then, the 10S AgCt prepared as above
Emulsion 12A (IXIO moles) was added to tabular grain AgBrI emulsion IA (0.04 moles) and incubated at 40°C for 30
Stir for a minute.

The electron micrograph shows that the AgC6 was deposited at the corners of the tabular AgBrI crystal as a result of selective epitaxial growth. Please refer to FIG. 15, which shows an electron micrograph.

Margin Example 13: In this example, when a sufficient amount of iodide is present in the tabular silver bromoiodide host grains, even if the adsorbed locally dominant substances are absent, their The ability to selectively epitaxially grow AgCA on the corners of host grains will be explained.

Emulsion 13A Tabular AgBrI (12 moles of iodide) host grains This emulsion, prepared by double-jet precipitation, has a 3.6μ
It had an average grain diameter of m, and an average grain thickness of 0.09IRn. Particles with a thickness of less than 0.3 micrometers and a diameter of at least 0.6 micrometers are
It had an average aspect ratio of 0:1 and occupied more than 85% of the total projected area of all particles present. The particles contained 9 to 12 momoles of iodide that were uniformly introduced during the double jet precipitation process. This emulsion was spectrally sensitized with 0.6 mmol/A11 mol of dye.

Margin Emulsion 13B Emulsion 13B was prepared in the same manner as Emulsion 13A. However, in the case of the emulsion, chemical sensitization of the emulsion was performed prior to spectral sensitization. This chemical sensitization consisted of 3.4 W/Na2S, 0. - Performed at 65° C. for 10 minutes using 1 mole of 5H20/A and 1 mole of 1.7μ KAuCA,/Ag.

Emulsion 13C: Spectrally sensitized tabular grain AgBrI after selective epitaxial corner growth (iodide 12 mole emulsion 13C) at 40° C. by simultaneous addition of 0.1 mole AgN0. and 0.012 mole KI solution to emulsion 13C. pAg
was adjusted to 7.2. This emulsion was centrifuged and 1
．． 9.2.5 mol of Aget was resuspended in 85 x 10 mol of NaC411 in a 4011 tabular host grain emulsion (0.04 mol) at phi at 140°C.
0.55 mol NaC4 and 0 while holding at 7.5
．． 54 ru AgN0. The solution was double-jet added over 4 minutes, causing precipitation. This emulsion
It was then spectrally sensitized with 90.6 mmol of dye per 11 moles of A1.

In the case of emulsion 13C, which was spectrally sensitized after addition of hgct, most of the hllct was deposited exclusively at the corners of the tabular gBrl crystals. Figure 16 shows
This is a carbon replica electron micrograph of Emulsion 13C.

Emulsions 13A, 13B and 13C were coated, exposed and processed in a time development system as described in Example 2 above.

The results of the cefcytometry measurements are listed in Table M1 below.

Example 14: This example illustrates that epitaxial growth of AgCt on spectrally sensitized tabular grain MugBrI emulsions can be confined to less than an entire corner region.

Selective epitaxial growth of Ag ('A) on the corners of emulsion 14 host grains Emulsion 14 was prepared similarly to AgBr host grain emulsion IA described in Example 1 above. After precipitation, this emulsion was
．． 0 moles of AgN0. The pAg at 40° C. was adjusted to 7.2 by simultaneously adding 0.12 mol of Kl and 0.12 mol of Kl. Sodium chloride was then added to bring the chloride ions in the emulsion to 1.8 x 10-2 mol/I.

The emulsion was spectrally sensitized with 1.5 mmol/mg mol of dye and held at 40°C for 30 min.
Then, 1.2 mol-〇mu gct was added to a 9.51 ml host emulsion (3.9 mol) with 7.2 mol of PAg at 40°C.
2.19 mol NICA and 2.0 mol MugNo were precipitated by double jet addition of the solution over 4 minutes while holding at .

From the electron micrograph of Emulsion 14A, the Ag on the spectrally sensitized tabular grain AgBrI (6 mole iodide) emulsion
It was found that CA growth was generally confined to one corner of no more than six corners for each hexagonal tabular crystal. FIG. 17 shows a representative electron micrograph of this.

Example 15: This example describes the selective epitaxial growth of AgCt in the central annular region of a tabular silver bromoiodide host grain with low iodide content.

Emulsion 15A Tabular AgBrI (12 mole % iodide) host grains with a central band of AgBr 1,5-2-ten solution containing 0.12 moles of potassium bromide6. 1,12-1-yl KBrIil containing 0.12-1-il KI and 1.04
(7) AgNO, the solution was added in 1 minute at pBr = 0.92 (consuming 0.6- of the total amount of silver nitrate used), then the temperature was raised to 70 °C in 7 minutes. Ta.

Then, while maintaining constant pBr, 0.24 mol of! 2.0 molar KBr solution containing 0.0 molar and 2.0 molar AlN0. The solutions were added simultaneously at an accelerated flow rate (2.75X from start to finish) over 17.6 minutes (consuming 29.2- of the silver nitrate usage).

2.0 molar KBr solution and 2.0 molar AgNO while lowering the temperature to 55°C and maintaining a pBr of 900.92.
The solution was added over 2.5 minutes (consuming 11.7- of the total amount of silver nitrate used), then 2.0 mol of a 2.0 mol KBr solution containing 0.24 mol KI was added. AgN0. The solution was simultaneously added over 12.5 minutes at 55°C while maintaining a pBr of 0.92 (consuming 58.5- of the total amount of silver nitrate used).

In total, about 3.4 moles of silver salt were used. Add this emulsion to 3
Cool to 5°C, US Patent J112.614.9294
# and stored at pAgm 8.4 measured at 40°C. Obtained tabular grains A
gBrI (12 moles qb iodide) has a tabular grain with an average grain diameter of 1.8 μm and an average grain thickness of 0.
．． 13 μm and 9. Particles with a thickness of less than 0.3 micrometers and a diameter of at least 0.6 micrometers had an average aspect ratio of 13.8:1 and occupied 80-80% of the total projected area of the particles. .

Emulsion 15B Selective epitaxial growth of AgCt on annular sites of host grains 409 tabular I (iodide 12 mol Is) prepared as above 0.1 mol in host grain Emulsion 15A (0.04 mol) AgN0. Its pAg at 40 °C was adjusted to 7.2 by adding solution 0, then i, O
mA of 0.74 molar NaCLi1I-solution was added.

Next, 5 mol-0 μg gcA was added to the tabular host grain emulsion at a pAg of 1.0 while maintaining the pAg at 40CK at 7.5.
4 mol NaCl and 1.0 mol AgN0. 1 solution
Precipitation was achieved by double jet addition over a period of minutes.

Emulsion 15C Mug in a small number of sites included in the annular region of the host grain
Ct selective epitaxial growth emulsion 15C was prepared in the same manner as emulsion 15B. However, in the case of this emulsion,
0 while holding PAlr at 7.5 at 40°C.
．． 55 mol %aCA and 0.5 mol AgN0. Add reagents over 7.8 minutes.

A carbon replica electron micrograph of epitaxially grown AgCA/AgBrI emulsion 15B is shown in FIG. In the precipitation formation process of tabular MugBrI crystals, AgBr
Concentric internal hexagonal (triangular) rings were formed and AgCj was selectively deposited onto such AgBrI crystals. Here, AgC by epitaxial growth
It may be noted that A deposition can occur on the AgBr rings as discontinuous crystals and that the iodide 12 mole-0 tabular crystals were not spectrally sensitized. Similar results were observed for emulsion 15C. However, in the case of this emulsion, the slower the deposition of silver chloride by epitaxial growth, the fewer the number of epitaxially grown grains, and therefore the greater the degree of individual growth.

Example 16: This example describes the epitaxial growth of AgCt in the peripheral AgBr region of tabular AgBrI grains. Emulsion 16A A round platelet AgBrI (12 mol % iodide) host with peripheral AgBr region (16.6 mol% total) Particle 0.
1,5 Tigelatin solution containing 12 moles of potassium bromide 6,0! 1, containing 0.12 mol of KI, was mixed at 55°C with stirring and by the double jet method.
12 molar KBr solution and 1.0 molar AgN0. The solution was added in 1 minute at pBr = 0.92 (consuming 0.5 s of the total amount of silver nitrate used). The temperature was then raised to 70°C within 7 minutes.

Then, while maintaining constant pBr, a 2.0 molar KBr solution containing 0.24 molar Kl and 2.0 molar AgN0. The solutions were added simultaneously at an accelerated flow rate (4.OX from start to finish) over 30 minutes (
82.9- of the total amount of silver nitrate used).

The temperature was lowered to 55°C. 2.0 Molar KBr solution and 2.0 Molar AgN while maintaining a pBr of 0.92.
The 0° solution was added over a period of 3.75 minutes (consuming 16.6% of the total amount of silver nitrate used). A total of about 3.6 moles of silver salt were used. The emulsion was cooled to 35°C, washed by the coagulation method described in US Pat. No. 2,614,929, and stored at pAg = 8.4 as measured at 35°C. Obtained dried plate-like particles AgBrI (12 moles of iodide)
The emulsion had a tabular grain size of 2.2 grains and an average thickness of 0.09 μm. The particles with a thickness of less than 0.3 micrometers and a diameter of at least 0.6 micrometers had an average aspect ratio of 24=1 and occupied 80IIk of the total projected area of the particles.

Emulsion 16B Epitaxial growth of mugct in peripheral area Tabular shape A
A 16 μm gBrI (12 moles iodide) host grain emulsion was dispersed in 2.5 times its volume of distilled water, centrifuged, and then resuspended in distilled water. The final silver content was 1 mole Ag (9! in emulsion 1). Then 2
．． 5 mol of AgCj in 0.04 mol of host emulsion 16
To do this, 0.25 mol of NaC was precipitated onto A while maintaining the pAg at 6.75 at 40°C.
1 and 0.25 mol of AgN0. The solution was double jet added over 0.8 minutes. Next, this emulsion was subjected to 1.
Spectral sensitization was performed with a dye concentration of 0 mmol/1 mole of Al.

Electron micrographs of emulsion 16B reveal that the AgCt was deposited epitaxially along the edges of the spectrally unsensitized AgBr1 (12 moles iodide-)phos) grain emulsion. Selective growth of AgCt occurred in the peripheral region of the AgBr1 host crystal. FIG. 19 shows a representative electron micrograph of this.

Emulsion 16C Part K of sensitized emulsion 16j of emulsion 16A 3. OWvAir-F:
Le (7) Na28203'5H20 and 1.5 V'A
g 1 mol of KAuct4 was added. 10% of this mixture
Heat to 65°C for 1 minute, cool at 40″ct, and finally add 1.0 mm/mg 1 mole of pigment.

Emulsions 16B and 19C were coated on a cellulose triacetate support at a coverage of 1.619 silver/m2 and 3.58 Ii/m'' of silver and exposed and exposed in a development system for a time similar to that described in Example 2 above. The processed sensitometric measurements revealed that at equal Dmin (0,15), Emulsion 16B was 0.16 mgE more sensitive than Emulsion 16CK.

Note that emulsion 16B was not treated with either the chemical sensitizers Na28□O6 or KA a C10.

Example 17: This example describes selective deposition of AgCA on the MugBr core of a tabular grain AgBrI emulsion. Mu gct growths were internally sensitized with iridium. In the case of this emulsion, no spectral sensitization was performed prior to the addition of AgCt.Blank Emulsion 17A Tabular AgBr I grains with central AgBr region This emulsion was prepared by double jet precipitation. This emulsion consisted of a central AgBr region (6.7 moles of total grain) and a cyclic AgBrI (12 moles of iodide) region laterally surrounding this region. This emulsion layer,
Average particle diameter is 1.9 μm.

And the average particle thickness is 0.08 μm. Particles with a thickness of less than 0.3 micrometers and a diameter of at least 0.6 micrometers exhibited an average aspect ratio of 24:1 and occupied 80-80 of the total projected area of the particles.

Emulsion 17B This emulsion was prepared by spectrally sensitizing a portion of Emulsion 17 above with 0.6 mmol/mol Ag of Dye A.

Emulsion 17C Selective epitaxial growth of AgC2 on the central region of host grains A portion of the emulsion 17A was dispersed in distilled water, centrifuged, and then resuspended in a 1.85×10 mol N*CL solution. 0 then 10 momoles of *gct to 4
In the tabular host grain emulsion (0.04 mol) of No. 09, 4
0.55 mol NaCL and 0.5 mol AgN0.5 while maintaining the PAg at 0°C at 7.5. 17.
By double jet addition over 6 minutes,
precipitated. This emulsion was then mixed with 0.6 mmol/Ag
Spectrally sensitized with 1 mole of dye.

Emulsion 17D Emulsion 17D was prepared in the same manner as Emulsion 17c. However, in the case of this emulsion, the iridium sensitizer was added to the emulsion 15 seconds after starting the addition of the NaCl and AgN0° reagents.

Emulsions 17B, 17C and 17D were coated on a polyester support with 1.61117 m'' of silver and 3.5817 m2 of gelatin.
A layer of 410.54 g/m" Oce9 was coated on the emulsion layer with a coating weight of
**600W through o~6.0 step tablet
Exposure to 2850° for tungsten light source Kl/10 seconds. These coatings were prepared using N-methyl-p-aminophenolsulfur (Ilon')-ascorbic acid developer (Ilon') or N-methyl-p-7-aminophenolsulfite containing 10 g/l of sodium sulfite. 20 in ascorbic acid developer (B)
℃ for 6 minutes.

both surface and internal properties through the addition of sodium sulfite
became possible. Therefore, developer B was an "internal" developer (also referred to as a "total" developer) as used in the art. The percentage of actual round iron was determined by X-ray fluorescence. A curve of percentage of silver developed versus light exposure was then constructed. The results are reported in Table ■ below.

Emulsion 17 doped with iridium during the adhesion process of margin AgCt
The highest relative sensitivity was obtained when 1) was internally developed (surface plus). Emulsion 17D had low sensitivity when it was processed in a surface-only developer.

Comparable results could not be obtained with either emulsion 17B or 17C, which contained no iridium.90 These data were exposed to iridium and described in U.S. Pat. The samples were processed for 1 minute at 20° C. in a total (surface plus internal) developer of the same type. Another set of coatings was exposed and treated in a potassium dichromate bleach bath (1,3
2Cr207.4.7X10- to X 10-2 molar
% OH2So4) for 10 minutes at 20°C.

As shown in Table X, emulsion 17D is control emulsion 1.
The sensitivity was 1.05 log E higher than that of 7B. Bleaching of the control emulsion 17B coating removed most of the latent image. However, when the coating of Emulsion 170 was bleached, no significant loss of latent image occurred. This indicated that the bleaching properties of the latent image were very poor (because the latent image was located below the surface of the epitaxially grown HGCT phase).

FIG. 20 is an electron micrograph of emulsion 17C, showing p on the central AgBr region of the tabular AgBrI grains,
The epitaxial growth of get is shown.

View 21 is a secondary electron micrograph of emulsion 17C, further showing that the AgCt epitaxy is centrally located.

Example 18: In this example, A
Controlled local epitaxial growth of g5CN will be described.

Selective epitaxial growth of AgSCN at the edges as described in Example 1 above. P tabular AgBrI (6 mole iodide) host grain emulsion IA (0.04 mole)
．． 1 mol of AgN0. and 0.006 mol of KI at the same time, the PAg at 40°C was reduced to 7.
．． Adjusted to 2. Next, 1. Q ml of 0.13 molar Na5CN solution was added. Then 5 mol of Ag
S CN was added to the host emulsion with 0.25 mol of Na5CN and 0.25 mol of Na5CN at 40°C while maintaining the PAg at 7°5.
．． 25 moles of AgN0. The solution was precipitated by double jet addition over 16 minutes.

Emulsion 18B AgSCN Selective Epitaxial Growth in the Corners Emulsion 18B was prepared in the same manner as Emulsion 18A. However, in the case of this emulsion, 1.1 mmol/Ag of the emulsion was added prior to the double jet addition of Na5CN and AgN0°.
Spectrally sensitized with 1 mole of dye A.

From the electron micrographs of Emulsions 18A and 18B, it can be seen that Emulsion 18A, which was not spectrally sensitized prior to the addition of soluble silver salts and thiocyanate salts, showed selective deposition based on epitaxial growth of silver thiocyanate at the edges of the tabular AgBrI grains. It turns out that it happened. Figure 22 shows
A typical electron micrograph of Emulsion 18A. Emulsion 18
B (which was subjected to spectral sensitization prior to epitaxy formation) also resulted in the deposition of silver thiocyanate;

Example 19: This example describes further chemical sensitization of a tabular grain AgBr1 emulsion with selective Ag5CN epitaxy at the corners.

Emulsion 19A Chemically sensitized, selectively epitaxially grown Ag5CN growths in corners, tabular AgBr1 (6 mol% iodide) host grain Emulsion IA with 0.10 mol AgN0. and 0.006 molar KI solution were simultaneously added to give a pAg of 7.2 at 40°C.
It was adjusted to The emulsion was centrifuged and resuspended in distilled water. 1.0 in 409 emulsion (0.04 mol)
ml of 0.13M Na5CN solution was added. This emulsion was then mixed with 1.1 mmol/Ag of dye A.
was spectrally sensitized. Then 2.5 mol of Ag5CN was added into the host emulsion, 0.25 mol of Na5CN and 0.25 mol of A while maintaining the pAg at 40°C at 7.5.
gN0. The solution was precipitated by double jet addition over 8.1 minutes. Add this emulsion to 1.0
■Na2S2O3・5H2o/Ag1 mol and 1.0
■KAuCl4/Ag 1 mol (Na5CN and Ag
N0. Chemical sensitization was carried out by (adding 1 minute after starting the addition of reagents).

Emulsion 19A, prepared as described above, was coated, exposed and processed in a time development system as described in Example 2 above. Tabular AgBrI host grain emulsion IA with 7.5 inches of N
a2S20.・5H20/1 mole of Ag and 2.5 ■ K
Chemically sensitized with 1 mole of AuCl4/Ag for 10 minutes at 65°C, spectrally sensitized with 1.10 mmol/1 mole of Dye A, and then coated and tested as described for Emulsion A above. did. From the sensitometric measurement results, equal Dml. At level (0,10), the epitaxially grown Ag5CN/AgBrI emulsion is tabular AgBrI
It can be seen that the sensitivity was higher by 0.34 Log 'B sensitivity units than the host grain emulsion.

Example 20: In this example, AgS on tabular grain AgCt emulsion
The epitaxial growth of CN will be explained.

Tabular AgCt host particles containing 0.35% by weight of adenine and 0 CaC42
．． 5% # and NaBr is 1.25X10-mol
625% by weight of synthetic polymer, poly(3-thiapentyl methacrylate)-co-acrylic acid-co-2-methacryloyloxyethyl-1-sulfonic acid, sodium salt (2 nia), solution (P at 55°C) l= 2.6) 2.0
In step 1, 2.0 mol CaCl2 solution and 2.0 mol AgN
The O3 solution was added over a period of 1 minute (consuming o, oss of the total amount of silver nitrate used).

The chloride and silver nitrate solutions described above were then injected simultaneously at a controlled pCt and at an accelerated flow rate (2.3× from start to finish) over a period of 15 minutes (28.5× of the total amount of silver nitrate used). (consumes 8%). The chloride and silver nitrate solution described above was then added over a further 264 minutes (71.1 of the total amount of silver nitrate used).
%). 0 during approximately the first third of precipitation formation.
A 2 molar NaOH solution (3Q, QmA') was added slowly to maintain - at 55°C at 2.6. Approximately 2 in total
．． 6 moles of silver nitrate were used. The emulsion was cooled to room temperature, dispersed in 1 x 10-5 molar HNO3, precipitated and decanted. The solid phase was resuspended in a 3% by weight gelatin solution and the pAg at 40° C. was adjusted to 7.5 by addition of NaCl solution. The resulting tabular grain AgCt emulsion had an average grain diameter of 4.
3 μm, and the average thickness was 0.284.

The particles with a thickness of less than 0.3 micrometers and a diameter of at least 0.6 micrometers had an average aspect ratio of 15:l and occupied 8(l) of the total projected area of the particles.

Emulsion 20B Selective epitaxial growth of AgSCN at the edge Tabular AgCt host grain emulsion 20A (0.04 mol) prepared as described above 0.5 mol Na5 in 401
CN and 0.5 mol AgN0. Five moles of AgS CN were precipitated into the emulsion by adding the solution by double jet addition over 7.8 minutes.

From the electron micrograph of emulsion 20B, most of the Ag5CN is exclusively tabular AgC/! It became clear that the particles were attached to the edges of the crystal.

Figure 24 is a typical electron micrograph of this emulsion. The tabular AgCt crystals contained (110) and (111). However, in the case of Ag5CN, it was deposited without selection at both types of edge sites.

Example 21: This example describes controlled local deposition of AgBr on a spectrally sensitized tabular grain AgBr emulsion. The additional AgBr was deposited primarily on the corners, with some growth along the edges.

Emulsion 21A Controlled local growth of AgBr on AgBr host grains Tabular AgBr host grain emulsion 4A (as described in Example 4 above)
0.04 mol) 0.1 mol of AgN0. The PAg at 40° C. was adjusted to 7.2 by adding the solution.

This emulsion was mixed with 2.4 mmol/Ag 1 mol of dye E1 anhydro-5,5',6.6'-tetrachloro-1,1
Spectrally sensitized with '-diethyl-3,3'-bis(3-sulfobutyl)benzimidazolocardocyanine hydroxide triethylamine and held at 40°C for 5 minutes. 625 mol AgBr was then added to this tabular host grain emulsion to give a pAg of 7.2 at 40°C.
Precipitation was carried out by double jet addition of a 0.2M NaBr and 0.2M AgNO3 solution over 15.7 minutes while holding at .

FIG. 25 shows a carbon replica electron micrograph of this emulsion. It appears that there was some adhesion of silver bromide along the edges of the tabular grains. However, it is judged that the adhesion of the additional amount of silver bromide was mainly limited to the corners of the tabular grains. As seen in electron micrographs, small grains overlying the major faces of tabular grains are independent of the grains below them.

Example 22: In this example, A
Controlled local deposition of gBrI is described. Additional AgBrI was chemically sensitized during deposition and selectively deposited at the corners of the host particles.

Emulsion 22A Tabular AgBrI (6 mol% iodide) host grain Tabular AgBrI (6 mol% iodide) host grain Emulsion IA
4■ Na2S2O3・5H20/Ag1 mol + 4■
of KAuC1a/kg for 10 min at 60°C and then 1.2 mmol/kg
Spectral sensitization was performed with Dye A at 1 mol of Ag.

Selective growth of AgBr in the corners of Emulsion 22B AgBr I
I (6 mol % iodide) host grain emulsion 22A at 1.2
Spectrally sensitized with mmol/1 mol of Ag dye A, centrifuged and resuspended in distilled water. Then, 2.5 moles of AgBrI containing 6 moles of iodide were added to the above emulsion (40.10.04 moles) at a pA of 40°C.
A solution containing 0.188 mol KBr and 0.012 mol KI and 0.2 mol Ag while keeping g at 7.5
N0. The solution was precipitated by double-jet addition over 9.9 minutes. 1 from the start of precipitation
After 5 seconds, 1.0■ Na2S20.・5H20/Ag
1 mole and 1.0 μ of KAu ('t4/AN) were added. After precipitation was complete, the resulting emulsion was heated at 60° C. for 10 minutes.

From the electron micrograph of emulsion 22B, AgBr is AgB.
It was found that the r I host grains were deposited at the corners of the emulsion. FIG. 26 shows a typical electron micrograph.

Emulsions 22A and 22B were coated on a cellulose triacetate support at a coverage of 1.611/m2 silver and 73.5811/m2 gelatin and exposed and processed in a time development system similar to that described in Example 2 above. did. Sensitometric measurements revealed that at equal Dmin (0,2), emulsion 22B was more sensitive than emulsion 22A by 0.62 tag E.

Margin Example 23: In this example, a silver halide emulsion having tabular grains with an average aspect ratio greater than 8=1 will be described. These tabular grains have 2,44 moles of silver chloride deposited primarily at their corners and edges.

Emulsion 23A Tabular grain AgB with an average aspect ratio of 8.1:1
Preparation of rI Host A1 Tabular Grain AgBr Core Emulsion 0, well-stirred bone gelatin containing 142 moles of potassium bromide (1
, 5% by weight) aqueous solution 6. A 1.15 molar potassium bromide solution and a 1.0 molar silver nitrate solution were added to Ot at a constant flow rate over 2 minutes using the double jet addition method.

Upon this addition, the controlled pBr =0.
85 t-applied (consuming 1.75% of total silver usage). After a 30 second hold, a 2.0 molar silver nitrate solution was added to the emulsion at a constant flow rate over 7.33 minutes, resulting in a pBr f of 1.2 at 65°C.
2 (6.42%'i consumption of total usage of til). Then under controlled pBr (at 65°C) a 2.29 molar potassium bromide solution and 2.0
26 molar sodium nitrate solution by double-jet addition method at an accelerated flow rate (5.6X from start to finish).
(37.6* of total silver usage)
t' consumption). The emulsion was then adjusted to its pBr at 65°C of ~2.32 by adding a 2.0 molar silver nitrate solution at a constant flow rate over 6.25 minutes (6.85 molar of the total amount of silver used). ). 2.29
Addition of molar potassium bromide solution and 2.0 molar silver nitrate solution over 54.1 minutes with pBr = 2.32 (at 6.5 °C) controlled by double jet addition method applying constant flow rate. (4 of the total amount of silver used)
A total of about 9.13 moles of silver was used to prepare this emulsion. After precipitation, emulsion
Cool to -40°C and 1.65t of phthalated gelatin (
15.3 wt. Then 1
．． 551 bone gelatin (13.3% by weight) solution was added and the pH'i of the emulsion at 40° C. was adjusted to 5.5 and the PAir to 8.3.

The resulting tabular grain AgBr emulsion has an average grain diameter of 1
．． The average thickness was 0.12 μm and the average aspect ratio was 11.2=1.

B. Addition of the AgBr shell to 2.5 t of a well-stirred 0.4 molar aqueous potassium nitrate solution containing 1479.9 (1.5 mol) of the core emulsion.
A 7 molar potassium bromide solution and a 1.5 molar silver nitrate solution were added at a constant flow rate over 135 minutes using the double jet addition method. During this addition, a controlled pAg=8.2 (at 6s°C) was applied (5.
06 moles of silver consumed). After precipitation, the emulsion was cooled to t-40°C, and 1. A solution of Oj's phthalated gelatin (19,0 wts) was added and the emulsion was washed three times by the coagulation method described in Yutzi and Russell, US Pat. No. 2,614,929. Then 1.0 t of bone gelatin (14,5% by weight) solution was added and heated at 40 °C.
The PI-1'i of the emulsion was 5.5, and the pAg was 8.
．． Adjusted to 3.

The resulting tabular grain AgBr emulsion has an average grain diameter of 2
．． The average thickness was 0.27 μm and the average aspect ratio was 8.1:1. Further, a projected area of 80 seconds or more was provided by the tabular grains.

Emulsion 23B Soluble iodide (0.5 molti) locally dominant substance 40.0#
(0.04 mol) of host emulsion 23A at 40°C.
0.5 mole of iodide was added by introducing 0.4 mole of potassium iodide solution at a constant flow rate over a period of 10 minutes. This emulsion was centrifuged and the total volume was 40. (l
Resuspended in 1.8×10 molar sodium chloride solution until . Then 2.44 momoles of AgcL
91-7 PAg at 40°C in host grain emulsion
．． 0.55 mol NaCl and 0.5 while holding at 5
0 moles of AgN0. The solution was precipitated by double-shot addition at a constant flow rate over 3.9 minutes.

Most of the epitaxially grown AgCt was present exclusively at the corners of the tabular grains.

Emulsion 23C Spectral sensitizer locally dominant substance 40.0II (0.04 mol) in Emulsion 23A with 0.10
Moles of AgN0. pA at 40°C after adding the solution
g was adjusted to 7.2. Next, 1. Otnl's 0.
A 61 molar NaCt solution was added. This emulsion i0.84
mmol/Ag1 mole of anhydro-5,5',6
, 6'-tetrachloro-1,1'-diethyl-3,3
'-No(3-sulfobutyl)benzimidazolocal added cyanine hydroxide and held at 40°C for 16 minutes. Then 2.44 momoles of kgC
pAg' at 40°C in the l i host grain emulsion
0.55 mol NaCl and 0.50 mol AgN0. while holding at fr 7.5. The solution was precipitated by double jet addition at a constant flow rate for 3.9 minutes. Epitaxially grown hgct was formed at the corners and along the edges of the AgBr tabular grains.

Emulsion 23D (pair 1 ft) No Local Dominant Deposition by epitaxial growth was repeated in the absence of both iodide and spectral sensitizing dye.

Agct was randomly deposited over the entire surface of the host tabular grains.

Example 24: This example uses the previously cited Maskassky
We demonstrate that selective orientation of complex salt Φ-seeds at staggered edge sites can be achieved using high aspect ratio tabular grains of the type disclosed in the literature of K.K. According to such a host tabular grain, there are six edges existing in the dodecagonal projection plane, that is, the - set of crystal planes [this is considered to be the (111) plane], and six edges that alternate with these. 6 present in the second set of crystal planes [which are considered to be (110) crystal planes]
A projection surface formed from the edges is given.

The following margin emulsion 24A is a tabular host grain with a dodecagonal projection surface/IJ (3-
Thiopentylmethac, ryetokoacrylic acid-co-2-methacryloyloxyethyl-1-sulfonic acid, sodium salt) (polymer 0.625*, molar ratio 1:2 near), adenine (0,021 mol), odor Sodium (0)
,0126 mol) and calcium chloride (0.50 mol)
A 3.0 t aqueous solution was prepared at 55° C. and pH 2.6.

An aqueous solution of calcium chloride (2.0 mol) and nitrate mf & (2.0 mol) was added by double jet addition method at a constant flow rate over 2 minutes (3.98 of the total amount of silver used).
%). The halide and silver salt solutions described above were then added using accelerated flow rates (2.3X from start to finish) for an additional 15 minutes (consuming 49.7% of the total volume of the chute).

The solution of halide and silver salt described above was then added at a constant flow rate over a period of 10 minutes (consuming 46.4% of the total amount of silver used). The voice value was maintained at ~2.6 throughout. A total of 226 moles of silver was used to make this emulsion t-X. The tabular grains contained in the obtained AgCtBr(99,6:σ,4) emulsion have a dodecagonal projection surface, an average grain size of 3 μm, an average thickness of 0.25 μm, and 1
It has an aspect ratio of 2:1 and a projection area of 85-
The above was given by tabular grains.

Emulsion 24B Preferential attachment of AgBr on the tabular grains of AgCtBr emulsion 2615.9 kg of unwashed tabular grains kg C1Br emulsion 24A (1.13 mol) bromide) IJum aqueous solution (
0,128 mol) was added at a constant flow rate using the single jet addition method (5 minutes at 55° C.). Approximately 3.0 moles of bromide was added. (11) of tabular silver halide grains
1) Silver bromide was preferentially deposited on ethu.

Emulsion 24Bt was cooled to 20 DEG C., diluted in about 14,000 ml of distilled water, stirred, and allowed to settle. The supernatant was decanted, redispersed in emulsion t-3309 in 10% bone gelatin in water and adjusted to pi (5.5 and pAg 7.5) at 40°C.

Emulsion 24B'io, 5 mmol/kg 1 mol Anhi P
rho5-chloro9-ethyl-5'-phenyl-3'
-(3-sulfobutyl)-3-(3-sulfopropyl)
Sensitized with oxacardocyanine hydroxide and triethylamine salt. Then, this emulsion y21 o1n9/A
g 1 mole sodium thiosulfate 5 H2O, 160
0 m9/Ag 1 mole sodium thiocyanate and 5
Chemically sensitized with sodium tetrachloroaurate at ~/Ag1 mole and held at 55°C for 5 minutes.

Emulsion 24C A portion of AgBr emulsion 24A deposited randomly on the tabular grains of AgC4Br emulsion was washed in a manner similar to that described for emulsion 24B above. Then, the emulsion 't”0 after washing
．． 5 mmol/1 mole of Ag anhydro-5-chloro-
Spectrally sensitized with 9-ethyl-5'-phenyl-3'-(3-sulfobutyl)-3-(3-sulfopropyl)oxacalgecyanine hydroxide, triethylamine salt.

To this emulsion was then quickly added a sufficient amount of IJium bromide solution to provide it with 3 mole percent bromide (based on the moles of halodanide present in Emulsion 24A). This emulsion was then chemically sensitized according to the method described for Emulsion 24B.

Electron micrographs of this emulsion revealed that silver bromide was randomly deposited on the bottom surface of the grains.

Emulsion 24B and 24Ct 2.15 N/m of silver and 5.381 N/m of gelatin on cellulose triacetate support
It was applied at a coverage of 2. The resulting coating was exposed to a 600W 5500° tungsten light source for 1150 seconds through a continuous density wedge of gold θ˜4.0.

These coatings were processed in iN-methyl-p-aminophenol sulfate (Eton)-ascorbic acid surface developer at 20 DEG C. for 10 minutes.

From the sensitometric measurements, it was found that emulsion 25B, which has silver bromide epitaxially grown on (111) silver halide ethu, was different from the control emulsion 24C (randomly deposited on silver halide host tabular grains). It was found that the sensitivity was higher by about 0.25 togE compared to that of the present invention (with a reduced amount of silver bromide).

In the case of emulsion 24B, chemical and spectral sensitization was achieved in the presence of relatively low (0.1 molar) concentrations of soluble iodide.
When done, it was possible to gain additional photographic sensitivity. An additional emulsion of the same type as Emulsion 24B was prepared. These emulsions contain a spectral sensitizer of 0.6 mmol/Ag 1 mol, and 7.5~/Ag 1 mol of sodium thiosulfate 5H20, 16001! 1 mol of sodium thiocyanate and 1 mol of potassium tetrachloroaurate at 65°C.
In addition, these two
To one of the emulsions, 0.1 mol of sodium iodide was added before spectral sensitization. These emulsions were evaluated for photographic speed as described above. The coating containing the iodide treated emulsion had a high sensitivity that was 0.38 togE greater when it was compared to that of the non-iodide treated emulsion.

Margin Example 25 This example illustrates that emulsions according to the invention can exhibit higher forces and faster fixing speeds than comparable emulsions containing non-tabular host grains. explain.

Emulsion 25A Non-tabular silver bromoiodide host emulsion This emulsion was subjected to a conventional double jet precipitation method (=
4.5 and pAg=5. 9. Prepared at + (79°C).

The formation of a precipitate can be achieved by:
It was carried out in the same manner. The molar ratio of bromide to iodide is 77:
23 and 69, determined by tX-ray diffraction. Furthermore, the iodide was evenly distributed, as determined by X-ray diffraction. It had a volume.

! Epitaxial Growth of Mugct on Nontabular Emulsion 25A Based on the total amount of halide, 2.5 moles of silver chloride was epitaxially grown on the host octahedral grains of Emulsion 25A according to the following procedure. Emulsion 25A in an amount of 0.075 moles was placed in a reaction vessel and distilled water was added to give a final weight of 50.011.

A 0.735 molar NaCl solution of 1.25- was added.

Next, 2.5 mol of Aget was added to this emulsion at 40°C.
0.55-11-l NaCAl solution and 0.5 molar AgN under pAg = 7.5 controlled by
Precipitation was achieved by double jet addition of O3 solution at a constant flow rate for 5.5 minutes. Epitaxial growth occurred primarily at the corners of the host grains.

Emulsion Scheme 5C--Tabular grain silver bromoiodide host emulsion A high aspect ratio tabular grain silver bromoiodide emulsion was selected on the basis of an average grain volume of 2.6 cubic microns. This emulsion was qualitatively identical to Emulsion 25A; X-ray diffraction determined that the bromide to iodide molar ratio was 80:20 and that the iodide distribution was uniform. The emulsion had an average tabular grain diameter of 4.0 microns, an average tabular grain thickness of 0.21 tcm, an average aspect ratio of 19:1%, and an average grain volume of 2.6 tcm. More than 90 inches of the total projected area of the rodanized grains was occupied by tabular grains.

Emulsion 25D Epitaxial growth of hgct on the tabular grains of Emulsion 25C The same silver chloride deposition process as described in the preparation of Emulsion 25B was used. However, in the case of this emulsion, emulsion 25
Instead of Emulsion 25C, emulsion 25C was initially placed in the reaction vessel. Epitaxial attachment was observed primarily at the corners and edges of the host tabular grains.

Control emulsion 258t$ pan 2 on recycled steril film support
．． It was applied with a planting machine amount of 8397 m2 and gelatin 109/J. This coating film was coated with Stellate Butapure with a concentration of 0 to 6.0.
) (0,3011 degrees Ste, De) 600W 3
000° to a tungsten light source for 172 seconds and 2
Processed for 20 minutes at 0°C. emulsion 25D with silver 2
．． Emulsion 25D was coated at a coverage of 89 g/WL2 and gelatin lOvm2 and exposed and processed in the same manner as Emulsion 25B above. It exhibited better coverage compared to Emulsion 26B. Emulsion 25D exhibited a minimum density of 0.16 and a maximum density of 1.25 compared to a minimum density of 0.10 and a maximum density of 0.54 for control emulsion 25B. X-ray fluorescence analysis showed that 97.2- silver was developed at Dffl□ for the control emulsion coating and 100- for the tabular grain emulsion coating.
It became clear that - silver was developed.

Mutually independent untreated portions of Emulsion 25B and Emulsion 25D coatings are treated with thiosulfate) Lium fixing bath (Kodak F
-5) for various times at 20°C and then washed for 30 minutes. Silver remaining in m1JI was analyzed by X-ray fluorescence. As shown in Table X below, the fixing speed of the tabular grain epitaxially grown emulsion coatings was also greater than that of the octahedral grain epitaxially grown emulsion coatings.

Table X Control emulsion 25B Tabular grain emulsion 25D (Ji'/
m2) (Vn2)30' 2.12
2591 1.51 48160' 1.
29 541s 0.54 81%90'
0.60 7911 0.03 99112
0' 0.05 981 0 100q
I1150' 0 100s 0 1
00% (5) Effects and Advantages of the Invention The tabular halo l"sp silver emulsion of the present invention has high sensitization sites because the sensitization sites are located in relation to the tabular grains and preferably in relation to each other. It has a high sensitivity.

The present invention represents a significant improvement over the prior art in this field. In one aspect of the invention, Iia! The technique used, namely,
Very high sensitivities can be achieved with tabular grain emulsions according to the present invention that have not been sensitized with reduction, gold (Kikai II) and/or sulfur (intermediate chalcodan) sensitizers. Furthermore, a number of additional advantages can be directly attributed to the presence of the epitaxially deposited silver salt. These advantages are described in detail below. The emulsions of this invention also offer unique photographic response advantages over conventional non-tabular emulsions which carry epitaxially deposited salts on the grain surfaces.

By using emulsions according to the invention, especially emulsions with a large average grain diameter, the sharpness of the true image can be improved. When the emulsions of the present invention are spectrally sensitized outside the true region of the spectrum, they exhibit greater sensitivity separation in the curved region of the spectrum than in the region to which they are spectrally sensitized. Present. Negatively sensitized emulsions containing tabular silver bromide and silver bromoiodide host grains according to the present invention have much less sensitivity to blue light than to negative blue light and are also sensitive to, e.g. When exposed to neutral light, such as daylight, filter maintenance is unnecessary to produce an acceptable negative exposure record. Using a back spectral photosensitizer, it was possible to achieve a very large increase in growth sensitivity compared to the original sensitivity exhibited by the emulsions of the present invention.

The emulsions according to the invention can be used in any photographic application, for example in radiographic elements coated on both major sides of a radiolucent support.

A comparison of a radiographic element containing an emulsion according to the invention with a similar radiographic element containing a conventional emulsion shows that reduced crossover can be achieved with the emulsion according to the invention. I understand. In some cases, emulsions of the present invention may be used to provide a comparable or loss-of-loss ratio when using reduced silver coverage and/or when providing an improved speed-granularity relationship.
A 9-value can be achieved.

The emulsions according to the invention can also be used in mounted transfer film units. Image transfer films≧nits can form a visible image with a short elapsed time after the start of processing. A transfer image with higher contrast can be realized with a shorter development time. Furthermore, by using such an image transfer film unit, it is possible to form images with improved sharpness.
more efficient use of dye image-forming materials in image transfer films, more advantageous layer configurations, omission or reduction of yellow filter material, and in general! Enables reduction of temperature dependence of iI#.

Margin below

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between granularity and sensitivity; Figure 4 is a conceptual diagram of an apparatus for quantitatively measuring light scattering;
2, 3, 5, 6, 7, 8, 9, 10, 14a, 11b, Ir12, 13, 14 Fig. 1515N, Fig. 16, Fig. 1
7, 818, 19, 20, Ir21, 22, 23, 24, 25, and 26 are electron micrographs of emulsion samples, respectively. In Figure 1, Yu, 2. ．． l, 4-. ';'', 6.'i' vertical g+
cl derede"r, ha0geni and nod 1'JJ$7゜Patent applicant Eastman Koda, Ri Kanno mother's patent application agent Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney 1) Yukio Patent Attorney Akira Yamaguchi FIG, / 2 3 111 RG, 4 FIG, 5 ゛FIG, /2 bσ15 FIG 23 F/ni 24

Claims (1)

[Scope of Claims] 1. A tabular grain silver halide emulsion comprising a dispersion medium and silver halide grains, wherein at least 50 of the total projected area of the silver halide grains has a thickness of 0.5 Less than a micrometer, with a diameter of at least 0
．． 6 micrometers, and the average aspect ratio is 8=
It is occupied by tabular silver halide grains having a size larger than l, the opposing parallel (111) main crystal planes forming a boundary between the tabular silver halide grains, and the remains of the tabular grains. A tabular grain silver halide emulsion characterized in that a silver salt is arranged on the separated surface portions.