JP3193381B2 - Method for producing tabular grains - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for producing a radiation (or radiation) sensitive silver halide emulsion.

BACKGROUND OF THE INVENTION In the 1980's, improved speed-granularity relationships in both single and multiple emulsion layer formats, increased covering power both on an absolute basis and as a function of binder cure, A wide range of photographic advantages such as faster developability, increased thermal stability, increased separation of natural and spectral sensitization to provide imaging sensitivity, and improved image sharpness have been achieved in high and medium aspect ratio tabular grains. Significant progress has been made in the field of silver halide photography based on the discovery that it can be obtained by using emulsions.

An emulsion is generally understood to be a "high aspect ratio tabular grain emulsion" if tabular grains having a thickness of less than 0.3 .mu.m have an aspect ratio greater than 8 and account for more than 50% of the total projected area. Have been. The aspect ratio of a tabular grain is its thickness (t) of its equivalent circular diameter (ECD)
Is the ratio to The equivalent circular diameter of a grain is the diameter of a circle having an area equal to the projected area of the grain. The term "medium aspect ratio tabular emulsion" refers to 5-8 tabular grains having a thickness greater than 0.3 μm and / or a lower grain average ECD.
Used when an average aspect ratio within the range is indicated. Generally, tabular grain emulsions exhibit an average tabular grain aspect ratio of at least 2. The term "lamellar grains" is generally understood to be tabular grains having a thickness of less than 0.2 μm. The term `` ultrathin tabular grains '' is generally 0.
It is understood to be tabular grains having a thickness of 06 μm or less. The term "high chloride" refers to particles containing at least 50 mole percent chloride, based on silver. For mixed halide containing grains, the halides are named in order of increasing molarity. For example, silver iodochloride contains a higher molar concentration of chloride than iodide.

The overwhelming major component of tabular grain emulsions includes tabular grains, which are irregular octahedral grains. An octahedral particle contains eight identical crystal planes, each of which is in a different {111} crystallographic plane. ｛11 for flat irregular octahedron
Includes two or more parallel twin planes that separate the two main crystal planes that lie within the 1｝ crystallographic plane. The {111} major faces of the tabular grains exhibit a triangular or hexagonal triple symmetry. The tabular form of the grains shows that after the inclusion of parallel twin planes, the twins form edge sites that favor silver halide precipitation, with the result that the grains grow on the sides, with a slight increase in thickness, if any. It is generally accepted that it is the result of making.

Although tabular grain emulsions are advantageously used in a wide variety of photographic and radiographic applications, the need for parallel twin plane formation and {111} crystal planes places limitations on both emulsion production and use. Bring. These disadvantages are most pronounced considering tabular grains containing high chloride concentrations. It is generally accepted that silver chloride grains are likely to form cubic grains, ie, grains bound by six identical {100} crystal faces. Tabular grains bound by {111} faces in silver chloride emulsions often return to nontabular if not morphologically stabilized.

1980 high and medium aspect ratio tabular grain silver bromide emulsion
Known in the art long before the decade, U.S. Pat. No. 4,399,215 to Wey et al. Produced first tabular grain silver chloride emulsions. The tabular grains were of the twin type showing the principal plane of triple symmetry existing on the {111} crystallographic plane. An ammoniacal double jet precipitation method was used. The thickness of the tabular grains was higher compared to contemporary silver bromide and silver bromoiodide tabular grain emulsions because the ammonia ripener thickened the tabular grains. In order to effect ammonia ripening, it was also necessary to precipitate the emulsion at a relatively high pH, which was known to produce elevated minimum concentrations (fog) in high chloride emulsions. Further, the tabular grains, for which both bromide and iodide ions were determined to prevent deterioration, were removed from the tabular grains at the beginning of their formation.

In U.S. Pat. No. 4,414,306 to Wey et al., A twinning method was developed to produce silver halide emulsions containing less than 40 mole percent chloride, based on total silver. This process has not been successfully extended to high chloride emulsions. The highest average aspect ratio reported in the example was 11.

No. 4,400,463 to Maskasky (hereinafter Maskasky)
I)) to produce high chloride emulsions containing tabular grains having tabular twin planes and {111} major crystal planes with significant advantages allowing significant internal inclusions of other halides. Strategy developed. The strategy was to use a specially selected synthetic polymeric deflocculant in combination with a grain growth modifier, whose function is to promote the formation of {111} crystal faces. It has been disclosed that adsorbed aminoazaindenes, preferably adenine and iodide ions, are useful grain growth modifiers.

Maskasky US Patent No. 4,713,323 (hereinafter Maskasky)
II) contains tabular grains having parallel twin planes and {111} major crystal planes using an aminoazaindene growth modifier and a gelatino-peptizer containing up to 30 micromol / g methionine. The production of high chloride emulsions has significantly advanced the state of the art. If the methionine content of the gelatino-peptizer is undesirably high, a strong oxidizing agent (or
Maskasky II can be readily reduced by treatment with an alkylating agent, King et al., U.S. Pat. High chloride tabular grain emulsions containing ions were within the skill of the art.

Maskasky I and II have stimulated further studies of grain growth modifiers that can produce high chloride emulsions of similar tabular grain content. U.S. Pat.No. 4,804, Tufano et al.
No. 621 uses di (hydroamino) as a particle growth modifier
Azines are used in U.S. Pat.No. 4,783,398 to Takada et al.
The term uses heterocycles containing divalent sulfur ring atoms,
U.S. Patent No. Is used.

Bogg U.S. Pat. No. 4,063,951 reports a first tabular grain emulsion in which the tabular grains have parallel {100} major crystal faces. Bogg's tabular grains exhibited square or rectangular main crystal faces, so there was no triple symmetry of conventional tabular grains {111} main crystal faces. In only one case, Bogg
The ammonia ripening method was used to produce silver bromoiodide tabular grains having an aspect ratio in the range of 4: 1 to 1: 1. The average aspect ratio of this emulsion was reported to be 2, and the highest aspect ratio grains (Grain A in FIG. 3) were reported to be only 4. Bogg states that this emulsion can contain up to 1% iodide, and uses only 99.5% bromide 0.5% iodide emulsions. Attempts to produce tabular grain emulsions by the Bogg method have been unsuccessful.

Mignot, U.S. Pat. No. 4,386,156, shows an improvement over Bogg that avoids the disadvantages of ammonia ripening in making silver bromide emulsions containing tabular grains having square and rectangular major crystal faces. Mignot specifically requires ripening in the absence of silver halide ripening agents other than bromide ions (eg, thiocyanates, thioethers or ammonia).

Endo and Okaj, "Empirical rules for modifying the crystal habit of silver chloride to form tabular grains in emulsions (An Empiric
al Rule to Modify the Habit of Silver Chloride to
form Tabular Grains in an Emulsion) ", The Journa
l of Photographic Science, 36, 182-188, 1988, discloses a silver chloride emulsion prepared in the presence of a thiocyanate ripening agent. Emulsion preparation by the disclosed method produced emulsions containing few tabular grains within the general grain population exhibiting mixed {111} and {100} crystal faces.

Mumaw and Haugh, "Silver halide precipitation coagulation method (Silv
er Halide Precipitation Coalescence Processe
s) ", Journal of Imaging Science, Vol. 30, No. 5, No. 9
Mon / October, 1986, pp. 198-299, essentially Endo and Oka
It is a repetition of ji and section IV-B is particularly relevant.

Symposium: Torino 1963, Photographic Scienc
e, C. semerano and U. Mazzucato, Ed., Focal Press, 52-5
Page 5 discloses the ripening of cubic grain silver chloride emulsions at 77 ° C. for several hours. During ripening, tabular grains appeared and the original cubic grains were reduced by Ostwald ripening. As shown by the comparative examples below, after 3 hours of ripening, the tabular grains occupied only a small portion of the total grain projected area, and only a small portion of the tabular grains were less than 0.3 μm thick. In further work that went beyond the practical teachings given, prolonged ripening removed many smaller cubic grains but also degraded many tabular grains to a thicker form.

JP-A-2-024643 published on January 26, 1990 is PCT
Although cited in the search report as being relevant to the claimed subject matter, it is not relevant in the applicant's view. The claims are directed to negative emulsions containing hydrazide derivatives and tabular grains having an equivalent circular diameter of 0.6 to 0.2 µm. Only conventional tabular grain production is disclosed, and only silver bromide and silver bromoiodide emulsions are illustrated.

In the production of silver halide emulsions, the most common method is to carry out the entire precipitation reaction in a single reaction vessel. Nevertheless, the so-called “dual-zon
e) Precipitation has also been reported. In a dual band configuration,
Silver and halide ions are combined in a first region to form grain nuclei and then transferred to a second region for grain growth.
For many years, emulsions have shifted from the second (growth) area to the first (nucleation)
Arrangement which, although more recently, does not recycle any portion of the emulsion from the second (growth) region to the first (nucleation) region, thereby completely separating grain nucleation from grain growth. Was reported. Mign is a specific illustration of double-zone precipitation
ot U.S. Pat.No. 4,334,012, Urabe U.S. Pat.
No. 208 and EP-A-326,852,
326,853, 355,535, 370,116, 368,2
Nos. 75 and 374,954.

SUMMARY OF THE INVENTION In one aspect, the present invention provides a method for manufacturing a semiconductor device comprising:
Tabular grains exhibiting {100} major faces with an adjacent edge ratio less than 0 account for at least 50% of the total grain projected area, and have iodide and at least 50 mol% chloride at their nucleation sites. (1) introducing a silver salt and a halide salt and a dispersion medium into a continuous double jet reactor to form at least 50 moles of a halide present in the dispersion medium. % Nucleation of tabular grains in the presence of iodide with chlorides in the proportion of 0.5% to maintain the pCl of the dispersing medium in the range of 0.5 to 3.5; The present invention is directed to a method comprising the step of completing grain growth in a reaction vessel that receives an emulsion from a continuous double jet reactor under conditions that maintain {100} major surfaces of the granular particles.

The present invention is based on the discovery of a novel approach to forming tabular grains. Brings flatness, thereby reducing
1｝ When forming grains to produce tabular grains with major faces, maintain chloride ions in solution within a selected pCl range instead of including parallel twin planes within grains In combination with this, if iodide was present in the dispersion medium during the high chloride nucleation step in a continuous double jet reactor, the tabular grains, when transferred to the second reactor, had {100} crystal faces Has been found to result in the formation of grain nuclei that can grow to form a more connected tabular grain emulsion.

The present invention not only represents the discovery of a new method of making tabular grain emulsions, but the emulsions made by this method are also new. The present invention falls within the art of tabular grains bound by {100} crystal faces having halide content, halide distribution and grain thickness not heretofore realized. The present invention provides a first ultrathin tabular grain emulsion in which the grains are linked by {100} crystal faces. In a preferred form, the present invention provides intermediates and high aspect ratio tabular grain high chloride emulsions that exhibit high levels of grain stability. Unlike high chloride tabular grain emulsions, in which the tabular grains have {111} major faces, the emulsions of the present invention have a morphological stability adsorbed to the major faces of the grains to maintain their tabular morphology. No agents are required. Finally, although obviously applicable to high chloride emulsions, the present invention extends beyond high chloride emulsions to those containing a wide range of bromide, iodide and chloride concentrations.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a photomicrograph with shadow of a carbon particle replica of an emulsion of the present invention.

FIG. 2 is a photomicrograph with shadow of a carbon particle replica of a control emulsion.

 FIG. 3 is an illustrative view of a dual zone reactor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The photographically useful radiation-sensitive emulsions that can be prepared by the process of the present invention include a dispersion medium and a halogenated Includes those composed of silver particles. {Ten
0｝ Among the tabular grains connected by the main surface, (1) 10
Selected based on smaller adjacent major edge ratio, (2) thickness less than 0.3 μm and (3) higher aspect ratio criterion than all remaining tabular grains satisfying criteria (1) and (2) Those that account for 50% of the total grain projected area have an average aspect ratio of at least 2, preferably at least 5, and optimally greater than 8.

The identity of emulsions and the significance of selection parameters that satisfy the requirements of this invention can be better appreciated by considering typical emulsions. FIG. 1 is a photomicrograph with shadow of a carbon particle replica of a representative emulsion of the present invention and is described in detail in Example 1 below. It is immediately apparent that most of the particles have right-angled square (square or rectangular) faces. The rectangular shape of the grain plane indicates that these are {100} crystal faces.

The projected area of a few grains in a sample that does not have a square or rectangular face is noted for inclusion in the calculation of total grain projected area, but these grains are clearly tabular grains with {100} major faces. Not part of a group.

Few particles, which are needle-like or rod-like particles (hereinafter referred to as rods), may be observed. These grains are ten times longer in one dimension than all other dimensions and are excluded from the desired tabular grain population based on their high ratio of edge length. The projected area occupied by the bars is low, but when the bars are present, their projected area is noted to determine the total grain projected area.

All the remaining grains have a square or rectangular major surface exhibiting a {100} crystal plane. Some of these particles are cubic particles. That is, they are particles having three mutually perpendicular edges of equal length. To distinguish cubic grains from tabular grains, it is necessary to measure grain shadow length. From knowledge of the shadow angle, it is possible to calculate the thickness of the particles from the measured shadow length. The projected area of a cubic grain is included in determining the total grain projected area.

To quantify the properties of the tabular grains, each grain-by-grain test of the residual grains representing a square or rectangular surface was performed.
-Grain examination) is required. The projected area of each grain is noted for determining the total grain projected area.

Each of the square or rectangular faces and particles having a thickness of less than 0.3 μm is tested. Focus on the projected area (product of edge length) of the upper surface of each particle. The ECD of the particle is calculated from the projected area of the particle. The thickness of the particle (t) and its aspect ratio of the particle (ECD / t) are then calculated.

After measuring all of the particles having a square or rectangular face and a thickness less than 0.3 μm, the particles are ranked by aspect ratio. The particles with the highest aspect ratio are ranked first and the particles with the lowest aspect ratio are ranked last.

Starting from the top of the aspect ratio rank, select enough tabular grains to account for 50% of the total grain projected area. Average the aspect ratio of the selected tabular grain population. In the emulsion of FIG. 1, the average aspect ratio of the selected tabular grain population is greater than 8. In particularly preferred emulsions according to the present invention, the selected tabular grain population has an average aspect ratio greater than 12, and optimally at least 20. The average aspect ratio of a typically selected tabular grain population is 50
Below, high aspect ratios of 100, 200 or more are feasible.

The selected tabular grain population, which accounts for 50% of the total grain projected area, preferably exhibits a major surface edge length ratio of less than 5, optimally less than 2. As the principal surface edge length ratio approaches 1 (ie, equal edge lengths), the probability of significant rod populations present in the emulsion decreases. It is further believed that tabular grains having smaller edge ratios are less susceptible to pressure desensitization.

Instead of ranking tabular grains occupying 50% of total grain projected area as described above to reach the average aspect ratio, the primary grain population in which tabular grains are present satisfies the requirements of the present invention. A simpler approach can be used in characterizing many of the emulsions.
According to this approach, the average grain ECD and average grain thickness (t) are obtained excluding only rods and grains without {100} major surfaces. The emulsions in each example require more effort when the average grain thickness is less than 0.3 μm and the average grain aspect ratio (ECD / t) meets selected criteria greater than 2, 5, or 8. It satisfies the above parameter requirements according to the ranking method.

In one particularly preferred form of the invention, the tabular grain population is selected on the basis of tabular grain thickness of less than 0.2 μm instead of 0.3 μm. In other words, in this example the emulsion is a thinner tabular grain emulsion.

Surprisingly, the ultrathin tabular grain emulsions prepared by the process of the present invention, the ultrathin tabular grain emulsions are prepared from tabular grains having a selected tabular grain population having a thickness of less than 0.06 μm. It was made. Prior to the present invention, the only ultrathin tabular grain emulsions of the halide moiety exhibiting a cubic crystal lattice structure known in the art include:
Tabular grains bound by 1｝ major surfaces were included.
In other words, it was thought to be essential to form tabular grains by the mechanism of containing parallel twins in order to obtain ultrathin dimensions. The selected tabular grain population extends to 0.02 μm
Emulsions having an average thickness as low as 0.01 μm can be produced according to the present invention. Ultrathin tabular grains have very high surface-to-volume ratios. This causes the ultrathin tabular grains to be processed photographically at an accelerated rate. Furthermore, when spectrally sensitized, the ultrathin tabular grains exhibit a very high sensitivity ratio in the spectral region of sensitization as compared to the spectral region of natural sensitivity. For example, ultrathin tabular grain emulsions prepared in accordance with the present invention have a completely negligible level of blue sensitivity, and thus exhibit minimal blue contamination even when arranged to receive blue light. Green or red records can be provided.

The characteristics of tabular grain emulsions that distinguish them from other emulsions are
It is the ratio to the thickness (t) of the ECD. This relationship has been quantitatively expressed in terms of the aspect ratio. Another quantification that is believed to more accurately assess the importance of tabular grain thickness is tabularity.

T = ECD / t ² = AR / t where T is the flatness, AR is the aspect ratio, ECD is the equivalent circular diameter in micrometers (μm), and t is the particle in micrometers. Thickness.

The selected tabular grain population accounting for 50% of the total grain projected area is preferably greater than 25, most preferably 100
Indicates greater flatness. Since the selected tabular grain population can be ultrathin, it is clear that very high tabularities, up to 1000 and higher, are within the contemplation of the present invention.

The selected tabular grain population may exhibit an average ECD of any photographically useful size. Average ECDs in most photographic applications rarely exceed 6 μm, but for photographic utility, an average ECD of less than 10 μm is contemplated. Within ultrathin tabular grain emulsions satisfying the requirements of the present invention, it is possible to meet intermediate aspect ratio requirements with an ECD of the selected tabular grain population of 0.10 μm and smaller. As generally understood by those skilled in the art, emulsions comprising a selected tabular grain population having a higher ECD are advantageous for obtaining relatively high levels of photographic speed, while
Selected tabular grain populations having a lower ECD are advantageous for obtaining low levels of granularity.

A photographically desirable grain population is available so long as the selected population of tabular grains satisfying the above parameters occupies at least 50% of the total grain projected area. 0.3μm
It is noted that the advantageous properties of the emulsions of the present invention increase as the population of tabular grains having a smaller thickness and {100} major faces increases. Preferred emulsions according to the present invention have at least 70% of the total grain projected area, optimally at least 90%.
% Is occupied by tabular grains having {100} major faces. It is specifically intended to provide an emulsion that satisfies the above grain description wherein the selection of ordered tabular grains is extended to tabular grains sufficient to account for up to 70% or even 90% of total grain projected area.

The remainder of the total grain projected area may be occupied by any combination of co-precipitated grains, as long as the tabular grains having the desired properties described above occupy the required ratio of total grain projected area. Of course, blending the emulsions to obtain a particular photographic objective is a common practice in the art. Blend emulsions that satisfy the selected tabular grain description above are specifically contemplated.

If tabular grains having a thickness of less than 0.3 .mu.m do not account for 50% of the total grain projected area, the emulsion does not satisfy the requirements of the present invention and is generally a photographically inferior emulsion. For most applications, especially those requiring spectral reprints, requiring rapid processing and / or requiring minimal silver coverage, for the most part all tabular grains will be relatively thick Emulsions, such as those containing a high proportion of tabular grains having a thickness greater than 0.3 μm, are poorly photographically.
Emulsions containing thicker (<0.5 μm) tabular grains with {111} major faces are generally inferior, but in the spectral region where silver halide exhibits natural sensitivity (eg, blue light) It has been suggested for use in the art to maximize light capture. If desired, emulsions containing thicker tabular grains having {100} major faces can be applied to similar applications.

More generally, poor emulsions made by methods that have failed to satisfy the requirements of the present invention have an excessive proportion of total grain projected area occupied by cubes, twin non-tabular grains and rods. Have. Such an emulsion is shown in FIG. Most of the grain projected area is occupied by cubic grains. It can also be asserted that the number of rod-like objects is much larger than that in FIG. Although there are a few tabular grains, they account for only a small portion of the total grain projected area.

FIG. 1 manufactured by a method satisfying the requirements of the present invention.
And the predominantly cubic grain emulsion of FIG. 2 were prepared under the same conditions except that iodine was controlled during nucleation. The emulsion in FIG. 2 is a silver chloride emulsion, while
The emulsion of FIG. 1 also contains a small amount of iodide contained during nucleation.

The preferred method for obtaining high chloride {100} tabular grain emulsions of the type described above has been realized by the discovery of a novel double zone precipitation method. A preferred dual zone precipitation apparatus is shown in FIG. In FIG. 3, a continuous double jet nucleation reactor 1
Is adapted to receive the dispersion medium through jet 2, the silver salt solution through jet 3, and the halide salt solution through jet 4. The silver salt and the halide salt react in the reactor to form grain nuclei. The reaction mixture containing the particle nuclei is then represented by arrow 5,
Liquid medium 7 consisting of the initially present dispersion medium and / or the faster transported part of the emulsion formed in the nucleation reactor
Is transferred to the growth reaction vessel 6 containing. A stirrer 8 is provided in the growth reaction vessel as shown. If desired, additional silver and halide ions can be provided to the growth reaction vessel.

In the dual zone precipitation process of the present invention, grain nucleation occurs in a high chloride environment in the presence of iodide under conditions favoring the appearance of {100} crystal faces. When grain formation occurs, the iodide content in the cubic crystal lattice formed by silver ions and the remaining halide ions is disintegrating due to the larger diameter of iodide ions compared to chloride ions. is there. The contained iodide ions cause crystal irregularities that become tabular grains instead of regular (cubic) grains during the next grain growth.

It is believed that the inclusion of iodide ions in the crystal structure at the onset of nucleation will result in the formation of cubic nuclei with one or more irregularities on one or more cubic crystal faces. The cubic crystal plane containing at least one disorder then accepts silver halide at an accelerated rate relative to the regular cubic crystal plane (ie, one lacking disorder). When only one of the cubic crystal faces contains irregularities, grain growth on only one face is accelerated and the grain structure obtained by continued growth is a rod. Cubic crystal structure 2
The same result occurs when only two opposing parallel planes contain growth acceleration irregularities. However, when any two adjacent cubic crystal faces contain irregularities, continued growth accelerates growth on both faces, creating a tabular grain structure.
The tabular grains of the emulsions of the present invention contain 2
It is believed to be made from these particle nuclei with one, three or four faces.

In accordance with conventional methods, both the nucleation reactor 1 and the growth reaction vessel 6 are fitted with a conventional silver and reference electrode for monitoring the halide ion concentration in the dispersion medium. At least 50 mol% is chloride, i.e., halide ions that are at least half the number of halide ions in the dispersion medium are chloride ions are placed in the nucleation reactor. The pCl of the dispersing medium is adjusted to favor the formation of {100} grain faces during nucleation, i.e. in the range from 1.0 to 3.0, optimally in the range from 1.5 to 2.5.

Since the precipitation is performed in the presence of a stoichiometric excess of halide ions, the dispersion medium jet and the halide jet are initially open. The grain nucleation step begins when the silver jet is open to introduce silver ions into the dispersion medium. The iodide ions are preferably introduced into the dispersion medium simultaneously with or optimally before the opening of the silver jet. Effective tabular grain formation can occur over a wide range of iodide ion concentrations, up to the saturation limit of iodide in silver chloride. The saturation limit of iodide in silver chloride was determined by H. Hirsch in “Photographic Emulsion Grains with Cores: Part IE
vidence for the Presence of Cores ", J.of Photog.Sci
ence, 10 (1962), pp. 129-134. In a silver halide grain having an equimolar ratio of chloride ion and bromide ion, iodide of 27 mol% or less based on silver can be contained in the grain. It is preferred to carry out grain nucleation and growth below the iodide saturation limit to avoid precipitation of the separated silver iodide phase and thereby avoid the creation of additional types of unwanted grains. It is generally preferred that the iodide ion concentration in the dispersing medium be kept below 10 mol% at the onset of nucleation. In fact, only a small amount of iodide is required during nucleation to obtain the desired tabular grain population. Initial iodide ion concentrations down to 0.001 mol% are contemplated. However, due to the reproducibility of the results, at least 0.01 mol%,
Optimally, it is preferred to maintain an initial iodide concentration of at least 0.05 mol%.

In a preferred embodiment of the present invention, silver iodochloride grain nuclei are formed during the nucleation step. Small amounts of bromide ions may be present in the dispersion medium during nucleation. During nucleation, any amount of bromide ion that is compatible with at least 50 mole percent of the halide in the grain nucleus, which is chloride, may be present in the dispersion medium. The grain nuclei preferably contain at least 70 mol%, optimally at least 90 mol% chloride, based on silver.

Grain nucleation occurs immediately upon introduction of silver ions into the dispersion medium. The nucleation reactor can be operated in a steady state continuous manner for any desired time. As precipitation continues, the reaction stream 5 can be switched from one growth reaction vessel to another.

During the nucleation step, any convenient sources of silver and halide can also be used. Silver ions are preferably introduced as an aqueous silver salt solution such as a silver nitrate solution. The halide ions are preferably introduced as alkali or alkaline earth halides, such as lithium, sodium and / or potassium chlorides, bromides and / or iodides.

During the nucleation step, silver chloride or silver iodochloride Lippmann grains can be introduced into the dispersion medium, but are not preferred. In this case, particle nucleation has already occurred, and what is shown above as a nucleation step is actually a step of introducing irregularities in the particle surface. The disadvantage of slowing the introduction of grain-plane irregularities is that this makes tabular grains thicker than would otherwise be obtained.

The dispersion medium introduced into the nucleation reactor consists of water and peptizer. The dispersing medium may exhibit a pH within any convenient conventional range for silver halide precipitation, typically between 2 and 8. Increase the pH of the dispersion medium to the neutral acidic side (ie, <7.0)
It is preferred, but not necessary. Mineral acids such as nitric acid or hydrochloric acid and bases such as alkali hydroxides can be used to adjust the pH of the dispersion medium.
It is also possible to include a pH buffer.

The peptizers may take any convenient conventional form known to be useful in the precipitation of photographic silver halide emulsions, especially tabular grain silver halide emulsions. For an overview of conventional peptizers, see Research Disclosure, Volume 308, December 1989.
Month, Item 308119, given in Section IX. Resea
rch Disclosure is available from Kenneth Mason Publications, Ltd ,.
Emsworth, Hampshire P010 7DD, published from the UK. Maskasky I, cited above and incorporated herein by reference.
However, it is preferred to use gelatino-peptizers (eg, gelatin and gelatin derivatives). The use of deionized gelatino-peptizers when manufactured and used in photography is a known method, but gelatino-peptizers typically contain significant concentrations of calcium ions. . In the former example, it is preferred to compensate for calcium ion removal by adding alkaline earth or earth metal ions, preferably divalent or trivalent metal ions such as magnesium, calcium, barium or aluminum ions. . Particularly preferred peptizers are low methionine gelatin peptizers (ie, per gram of peptizer)
Containing less than 30 micromoles of methionine), and optimally containing less than 12 micromoles of methionine per gram of deflocculant. These deflocculants and their manufacture are described in the disclosures cited above. Maskasky II and King et al., Supra, which are incorporated herein by reference. However, grain growth modifiers of the type taught to be included in the Maskasky I and II emulsions (e.g., adenine) are those in which these grain growth modifiers are twinned and tabular having {111} major faces. It should be noted that it promotes the formation of particles and is not suitable for inclusion in the dispersion medium of the present invention. Generally, at least about 10%, typically 20-80%, of the dispersion medium forming the finished emulsion will be present in the reaction vessel at the beginning of the nucleation step. It is conventional practice to maintain relatively low levels of peptizer, typically 10-20% of the peptizer present in the finished emulsion, in the reaction vessel at the beginning of precipitation. To increase the proportion of thin tabular grains having {100} faces formed during nucleation, the concentration of the deflocculant in the dispersing medium is between 0.5 and 0.5% of the total weight of the dispersing medium at the start of the nucleation step. Preferably it is in the range of 6% by weight. It is conventional practice to add gelatin, gelatin derivatives and other vehicles and vehicle extenders to make the emulsion for coating after precipitation. Any naturally occurring levels of methionine may be present in the gelatin and gelatin derivatives added after precipitation is complete.

The nucleation step can be performed at any convenient conventional temperature for precipitation of silver halide emulsions. Temperatures near ambient temperature, for example in the range of 30 ° C to about 90 ° C, are contemplated, with temperatures in the range of 35-70 ° C being preferred.

Since grain nucleation occurs almost instantaneously, only a very small proportion of the total silver used to form the emulsion needs to be introduced during the nucleation step. Typically,
About 0.1 to 10 mole% of total silver is introduced through the nucleation reactor during the nucleation step.

In the growth reactor, the particle nuclei are {100} of the desired average ECD.
It grows until tabular grains having a major surface are obtained. While the purpose of the nucleation step is to form a population of particles having the desired contained crystal structure disorder, the purpose of the growth step is to avoid or minimize the production of additional particles.
The deposition of additional silver halide over existing (growing) grain populations. If additional grains are formed during the growing step, the polydispersity of the emulsion will increase and the additional steps generated in the growing step unless the conditions in the reaction vessel are maintained as described above for the nucleation step. Will not have the desired tabular grain properties described above.

It is generally preferred to produce a photographic emulsion having the most geometrically uniform grain population achievable. This is because this optimally sensitizes a higher percentage of the total grain population and would otherwise be optimally manufactured for photographic applications. Further, it is generally more common to blend relatively monodisperse emulsions to obtain the desired sensitometric profile than to precipitate a single polydisperse emulsion that matches the desired sensitometric profile. More convenient.

In preparing the emulsion according to the present invention, it is preferred to complete the nucleation step before adding additional silver and / or halide ions to the growth reaction vessel. In other words, it is preferable that there be a holding period in the growth reaction vessel before continuing the growth step of the manufacturing method. The emulsion is held in the above temperature range for nucleation for a period of time sufficient to reduce grain dispersity. The retention period can range from one minute to several hours,
Typical retention periods range from 5 minutes to 1 hour. During the holding period, the smaller grain nuclei are Ostwald ripened over the remaining larger grain nuclei, the overall result is a reduction in the particle dispersity.

If desired, the rate of ripening can be increased by the presence of a ripening agent in the emulsion during the retention period. The traditional simple approach to accelerating ripening is
The purpose is to increase the halide ion concentration in the dispersion medium. This forms a complex of silver ions with multiple halide ions that accelerate ripening. When using this approach, it is preferable to increase the chloride ion concentration in the dispersion medium. That is, it is preferred to lower the pCl in the dispersion medium to a range where increased silver chloride solubility is observed.
Also, by using conventional ripening agents, ripening can be accelerated and the percentage of total grain projected area occupied by {100} tabular grains can be increased. Preferred ripening agents are sulfur-containing ripening agents such as thioethers and thioisocyanates. Typical thioisocyanates are described in U.S. Pat.
No. 64; Lowe et al. U.S. Pat.No. 2,448,534 and Illingswort
h, U.S. Pat. No. 3,320,069, the disclosure of which is incorporated herein by reference. A typical thioether ripening agent is McBride U.S. Pat.No. 3,271,157, Jone
No. 3,574,628 to Rosenvrantz et al., US Pat. No. 3,737,313, the disclosures of which are incorporated herein by reference. More recently, the use of crown thioethers as ripening agents has been suggested. Ripening agents containing primary or secondary amino units such as imidazole, glycine or substituted derivatives are also effective. Sodium sulfite has also been shown to be effective in increasing the percentage of total projected area occupied by {100} tabular grains.

Once the desired population of particle nuclei is formed, particle growth is
It may be proceeded by any convenient conventional precipitation method for precipitating silver halide grains bound by {100} grain faces. Grain growth is continued until tabular grains having a thickness of less than 0.3 μm exhibit an average aspect ratio greater than 8. To be considered tabular, the grains must have an aspect ratio of at least 2.

Iodide and chloride ions need to be included in the grains during nucleation, so they are present in the grains completed at the internal nucleation sites, but during the growth process a cubic crystal lattice structure is formed. Any halide or combination of halides known to form can also be used. The disordered grain nuclei that result in tabular grain growth, once introduced, are independent of the halide that precipitates during subsequent grain growth, as long as the halide or combination of halides forms a cubic crystal lattice. There is no need to include iodide or chloride ions in the grains during the growth step since they remain. This is the level of only iodide above 13 mol% (preferably 6 mol%) when precipitating silver iodochloride and 40 mol% (preferably 30 mol%) when precipitating silver iodobromide.
(Mole%) higher iodide levels and proportionate intermediate levels of iodide in precipitating bromide and chloride containing silver iodide. During the growth process, when depositing silver bromide or silver iodobromide, pBr in the dispersion medium
Is maintained in the range of 1.0 to 4.2, preferably 1.6 to 3.4. During the growth step, when depositing silver chloride, silver iodochloride, silver bromochloride or silver iodobromochloride, the pC
It is preferred to keep l within the ranges described above when describing the nucleation step.

It was quite unexpectedly found that by including certain halides during grain growth, less than a 20% reduction in tabular grain thickness could be achieved. Surprisingly, the addition of bromide in the range of 0.05 to 15 mol%, preferably 1 to 10 mol%, based on silver, during the growth step, can be achieved under the same precipitation conditions in the absence of bromide ions. It was observed that relatively thin {100} tabular grains were produced. Similarly, 0.00 on a silver basis during the growth process
It has been observed that the addition of iodide in the range of 1 to <1 mol% produces {100} tabular grains that are relatively thinner than can be achieved under the same precipitation conditions in the absence of iodide ions. Was done.

During the growth step, both the silver salt and the halide salt are preferably introduced into the dispersion medium. In other words, double jet precipitation is contemplated, if any, with the remaining halide salt or with the added iodide salt being introduced through one independent jet. The rate at which the silver and halide salts are introduced is adjusted to avoid renucleation-the formation of a new grain population. The addition rate control to avoid renucleation is described in Wilgus, German Offenlegungsschrift (OL
S) No. 2,107,118; Irie U.S. Pat. No. 3,650,757; Kur
U.S. Patent No. 3,672,900 to Z; U.S. Pat.No. 4,242,4 to Saito
No. 45, Teitschied et al., European Patent Application No. 80102242 and Wey, "Growth Mechanism of AgBr Crystals in Gelatin Solutions"("G.
rowth Mechanism of AgBr Crystals in Gelatin Soluti
on "), Photographic Science and Engineering, Volume 21,
No. 1, January / February, 1977, pages 14 et seq., Which are generally well known in the art.

In one embodiment of the present invention, dual zone precipitation can be performed by recycling the contents of the growth reaction vessel to a nucleation reactor. Referring to FIG. 3, in this embodiment, a liquid medium 7 in a growth reaction vessel is supplied through a jet 2 to a nucleation reactor. This type of precipitation arrangement is disclosed in U.S. Pat.No. 3,790,386 to Posse et al., U.S. Pat.
No. 7,935, Finnicum et al. U.S. Pat.No. 4,147,551 and Verh
Illustrated by U.S. Pat. No. 4,171,224 to ille et al., which is incorporated herein by reference.

Various parameters important for regulation of particle formation and growth, such as pH, pAg, ripening, temperature and residence time, can be adjusted independently in separate nucleation and growth reaction vessels. In order to make the particle nucleation completely independent of the growth of particles occurring in the growth reactor below the nucleation reactor, a portion of the contents of the growth reactor is transferred to the nucleation reactor. Should not circulate. A preferred arrangement for separating particle nucleation from the contents of the growth reaction vessel is Mi
US Patent No. 4,334,012 to gnot, which also discloses useful features of ultrafiltration during particle growth, Urab
e U.S. Pat.No. 4,879,208 and Published European Patent Application Nos. Urabe et al. Published European Patent Application No. 0
No. 374954 and Onishi et al., JP-A-2-172817 (1990).
Year).

Emulsions which can be prepared by the method of the present invention include silver iodochloride emulsions, silver iodobromochloride emulsions and silver iodochlorobromide. Up to 10 ^-2 moles per mole of silver, typically 1
The dopant may be present in the grains at a concentration of less than 10 ^-4 mole per mole. Compounds of metals such as copper, thallium, lead, mercury, bismuth, zinc, cadmium, rhenium and Group VIII metals (eg, iron, ruthenium, rhodium, palladium, osmium, iridium and platinum) may be present during particle precipitation. , Preferably during the growth phase of the precipitate. Modification of photographic properties is related to the level and location of the dopant within the grain. When the metal forms part of a coordination complex, such as a hexacoordination or tetracoordination complex, a ligand may be included within the particle, and the ligand may further affect photographic properties. obtain. Ligands such as halo, aquo, cyano, cyanate, thiocyanate, nitrosyl, thionitrosyl, oxo and carbonyl ligands are contemplated and may be expected to modify photographic properties.

Dopants and their addition are described in U.S. Pat.
195,432; Hochstetter U.S. Patent No. 1,951,933; Tri
U.S. Pat.No. 2,448,060 to velli et al., U.S. Pat.No. 2,628,167 to Overman, U.S. Pat.
U.S. Pat.No. 3,287,136 to cBride, U.S. Pat.No. 3,488,709 to Sidebotham, U.S. Pat.
U.S. Pat.No. 3,687,676 to Spence et al., U.S. Pat.No. 3,761,267 to Gilman et al., U.S. Pat.No. 3,790,390 to Shiba et al.
U.S. Pat.No. 3,890,154 to Ohkubo et al., U.S. Pat.No. 3,901,711 to Iwaosa et al., U.S. Pat.No. 4,173,483 to Habu et al.
U.S. Pat.No. 4,269,927 to Atwell, U.S. Pat.No. 4,835,093 to Janusonis et al., U.S. Pat.No. 4,933,27 to Mcdugle et al.
Nos. 4,981,781 and 5,037,732, Keevert et al., U.S. Pat.No. 4,945,035, and Evans et al., U.S. Pat.
No. 024,931 (the disclosures of which are incorporated herein by reference). For background on alternatives known in the art, see BH Carroll,
“Iridium Sensit: Literature Review” (“Iridium Sensit
ization: A Literature Review "), Photographic Scien
ce and Engineering, Vol. 24, No. 6, November / December, 1980
Note, pp. 265-267, and published European Patent Application 0 264 288 to Grzeskowiak et al.

Conventional high chloride tabular grain emulsions with tabular grains linked by {111} are inherently unstable and the presence of morphological stabilizers to prevent the grains from reverting to nontabular shape The present invention is particularly advantageous in providing high chloride (greater than 50 mol% chloride) tabular grains because they require Particularly preferred high chloride emulsions are those according to the invention which contain more than 70 mol% (optimally more than 90 mol%) chloride.

Although not essential to the practice of the present invention, another method that can be used to maximize the population of tabular grains having {100} major faces is to provide non- {100} The purpose is to contain an agent capable of suppressing the appearance of the crystal plane of the particles. When used, this inhibitor
It may be active during particle nucleation, during particle growth or through precipitation.

Useful inhibitors under the intended conditions of precipitation are organic compounds containing a nitrogen atom with a resonance-stabilized π-pair of electrons. Resonance stabilization prevents protonation of the nitrogen atom under relatively acidic conditions of precipitation.

Aromatic resonance can be expected for the stabilization of the pi pair of nitrogen atoms. The nitrogen atom may be contained in an aromatic ring such as an azole or azine ring, or the nitrogen atom may be a ring substitute for an aromatic ring.

In one preferred form, the inhibitor has the formula: Wherein Z represents the atoms necessary to complete a 5- or 6-membered aromatic ring structure, preferably formed by carbon and nitrogen ring atoms. The preferred aromatic ring is 1
, Two or three nitrogen atoms. Particularly contemplated ring structures include 2H-pyrrole, pyrrole, imidazole, pyrazole, 1,2,3-triazole, 1,2,4-triazole, 1,3,5-triazole, pyridine, pyrazine, pyrimidine and pyridazine. Is included.

When the stabilized nitrogen atom is a ring substituent, preferred compounds have the formula: (Wherein, Ar is an aromatic ring structure having 5 to 14 carbon atoms, and
R ¹ and R ² are independently hydrogen, Ar or any convenient aliphatic group or together form a 5- or 6-membered ring).

Ar is preferably a carbocyclic aromatic ring such as phenyl or naphthyl. Also, any of the above nitrogen and carbon containing aromatic rings may be attached to the nitrogen atom of Formula II via a ring carbon atom. In this example, the resulting compound has the formula I and
II Satisfy both. Any of a wide variety of aliphatic groups can be selected. The simplest intended aliphatic group is an alkyl group, preferably an alkyl group having 1 to 10 carbon atoms, most preferably an alkyl group having 1 to 6 carbon atoms. Known to harmonize with silver halide precipitation,
A functional substituent of any alkyl group may be present. Cycloalkanes, cycloalkenes and oxygen and / or
It is also contemplated to use dry aliphatic substituents that exhibit a 5- or 6-membered ring, such as an aliphatic heterocycle, such as those containing a nitrogen heteroatom. Cyclopentyl, cyclohexyl, pyrrolidinyl, piperidinyl, furanyl and similar heterocycles are specifically contemplated.

The following are representative of compounds intended to satisfy Formulas I and / or II.

4 The selection of a preferred inhibitor and its useful concentration can be obtained by the following selection method. Compounds contemplated for use as inhibitors are added to silver chloride emulsions consisting essentially of cubic grains having an average grain edge length of 0.3 µm. This emulsion is 0.2M in sodium acetate, 2.1 p
It has Cl and has a pH at least one unit greater than the pKa of the compound under consideration. The emulsion is maintained at 75 ° C. for 24 hours with the inhibitor present. In the microscope test 24 hours later,
If the cubic particles have sharper {100} crystal face edges than the control, differing only in the point lacking the considered compound, the compound introduced acts as an inhibitor. The meaning of the sharper edges of the {100} crystal plane intersection lies in the fact that the particle edge is the most active site on the particle for ions re-entering the dispersion medium.
By retaining sharp edges, the inhibitor acts to suppress the appearance of non- {100} crystal faces, such as those present at rounded edges and corners. In some instances, instead of exclusive dissolved silver chloride deposition on the edges of cubic grains, a new population of grains bound by {100} crystal faces is formed. Optimum inhibitor activity occurs when the new grain population is a tabular grain population in which tabular grains are bound by {100} major crystal faces.

It is specifically contemplated to deposit the silver salt epitaxically on the tabular grains acting as hosts. Conventional epitaxy deposition on high chloride silver halide grains
asky U.S. Patent No. 4,435,501 (especially Example 24B); Ogawa et al. U.S. Patent Nos. 4,786,588 and 4,791,053;
Other U.S. Patent Nos. 4,820,624 and 4,865,962, Sugi
moto and Miyake, “Mechanism of Br ^- ion-converted colloidal AgCl microcrystal halides”
Halide Conversion Process of Colloidal AgCl Micro
crystals by Br ^- Ions "), Part I and Part II, Journal
of Colloid and Interface Science, 140, 2, 199
Dec. 0, pp. 335-361, Houle et al. U.S. Pat.No. 5,035,992
And JP-A-3-252649 (priority date: February 3, 1990)
JP-A-051165 Japan) and JP-A-3-288143 (priority date: April 4, 1990-JP 089380 Japan). The disclosures of the above U.S. patents are incorporated herein by reference.

The emulsion produced by the method of the present invention is
Author, The Theory of the Photographic Process ", 4th
Edition, Macmillan, 1977, pp. 67-76, or as described in Research Disclosure, 120.
Volume, April 1974, Item 12008, Research Disclosure, 13
4, June 1975, Item 13452, Sheppard et al., U.S. Pat.No. 1,623,499, Matthies et al., U.S. Pat.No. 1,673,522,
U.S. Pat.No. 2,399,083 to Waller et al., U.S. Pat.No. 2,642,361 to Damschroder et al., U.S. Pat.No. 3,297,447 to McVeigh
U.S. Pat.No. 3,297,446 to Dunn; British Patent No. 1315,755 to McBride; U.S. Pat.No. 3,772,031 to Berry et al., Gilm
an et al., U.S. Pat.No. 3,761,267; Ohi et al., U.S. Pat.
7,711; Klinger et al., U.S. Pat.No. 3,565,633; Oftedah
l U.S. Patent Nos. 3,901,714 and 3,904,415 and S
As shown in British Patent No. 1,396,696 of imons,
At a temperature of 30-80 ° C. at a pAg level of 5-10 and a pH level of 5-8, sulfur, selenium, tellurium, gold, platinum, palladium,
It can be chemically sensitized with an iridium, osmium, rhenium or phosphorus sensitizer or a combination of these sensitizers, optionally with chemical sensitization, as described in Damschroder U.S. Pat.
U.S. Pat.No. 2,521,926 to Lowe et al., U.S. Pat.No. 3,021,215 to Williams et al.
, A thioether compound as disclosed in
U.S. Patent No. 3,411,914; Kuwabara et al. U.S. Patent No.
U.S. Pat.No. 3,565,631 and Ofted et al.
Azaindene, azapyridazine and azapyrimidine, Miyo as described in U.S. Pat.No. 3,901,714 to Ahl
elemental sulfur as described in shi et al., European Patent Application EP 294,149 and Tanaka et al., European Patent Application EP 297,804, and thiosulfonates as described in Nishikawa et al., European Patent Application EP 293,917 Done in the presence of Additionally or alternatively, the emulsions may be prepared, for example, from Janusonis U.S. Pat.
U.S. Patent No. 3,984,249 to Bcock et al. with hydrogen, low pAg (e.g., below 5), high pH (e.g., above 8) treatment, or Allen et al.
2,983,609, Oftedahl et al., Research Disclosure, 136
Vol., August 1975, Item 13654, U.S. Pat.
U.S. Patent Nos. 8,698 and 2,739,060 to Roberts et al.
U.S. Pat.Nos. 2,743,182 and 2,743,183, Chambers et al., U.S. Pat.No. 3,026,203, and Bigelow et al., U.S. Pat.
Reduction sensitization can be achieved using reducing agents such as stannous chloride, thiourea dioxide, polyamines and amine borane as shown in No. 4.

Chemical sensitization is described in US Pat. No. 3,628,960 to Philippaerts et al.
U.S. Pat.No. 4,439,520 to Kofron et al., U.S. Pat.No. 4,520,098 to Dickerson, U.S. Pat.
No. 4,693,965 to Ihama et al. And U.S. Pat. No. 4,791,053 to Ogawa, in the presence of spectral sensitizing dyes. Chemical sensitization is directed to specific sites or crystallographic planes of silver halide grains as described in Haugh et al., British Patent Application 2,038,792A and Mifune et al., Published European Patent Application EP 302,528. Good. Sensitivity centers obtained by chemical sensitization are described in Morgan U.S. Pat.No. 3,917,485 and Becker U.S. Pat.
Issue and Research Disclosure, Vol.181, May 1979, Item
Partially or wholly by precipitation of an additional layer of silver halide using means such as twin-jet addition or pAg circulation with alternating addition of silver and halide salts as described in 18155. May be occupied by Also, as described in Morgan, cited above, the chemical sensitizer can be added before or simultaneously with the additional silver halide formation. Chemical sensitization may occur during or after halide conversion, as described in Hasebe et al., European Patent Application EP 273,404. In many instances, the epitaxy deposition on selected tabular grain sites (eg, edges or corners) is directed to chemical sensitization or to perform functions normally performed by chemical sensitization itself. Can be used for either.

The emulsions of the present invention can be spectrally sensitized with dyes from various types, including polymethine dye types, which include cyanine, merocyanine, complex cyanine, and merocyanine (ie, tri-, tetra-, and polynuclear). Cyanine and merocyanine), styryl, merostyryl, streptocyanin, hemicyanine, arylidene, allopolar cyanines and enamine cyanine.

Cyanine spectral sensitizing dyes include quinolinium, pyridinium, isoquinolinium, 3H-indolium, benzindolium, oxazolium, thiazolium, selenazolinium, imidazolium, benzoxazolium, benzothiazolium, benzoselenazolium, benzo Derived from terrazolium, benzimidazolium, naphthoxazolium, naphthothiazolium, naphthoselenazolium, naphthotellazolium, thiazolinium, dihydronaphthothiazolium, pyrylium and imidazopyrazinium quaternary salts And two basic heterocyclic nuclei linked by a methine bond.

The merocyanine spectral sensitizing dye includes one cyanine dye type basic heterocyclic nucleus bonded by a double bond or a methine bond, and barbituric acid, 2-thiobarbituric acid, rhodanine, hydantoin, Thiohydantoin, 4-thiohydantoin, 2-pyrazolin-5-one, 2-isoxazolin-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,
Benzoylacetonitrile, malononitrile, malonamide, isoquinolin-4-one, chroman-2,4-dione, 5H-furan-2-one, 5H-3-pyrrolin-2-one, 1,1,3-tricyanopropene and tellurium Acidic nuclei, as can be derived from cyclohexanedione.

One or more spectral sensitizing dyes can be used. Dyes are known which have a sensitizing maximum at wavelengths throughout the visible and infrared spectra and have a great variety of spectral sensitization curve shapes. The choice and relative ratio of dyes will depend on the region of the spectrum where photosensitivity is desired and the shape of the desired spectral sensitization curve. Dyes with overlapping spectral sensitization curves
Often the combination will result in a curve in which the sensitivities at each wavelength within the region of overlap are approximately equal to the sum of the sensitivities of the individual dyes. That is, in order to obtain a spectral sensitization curve having an intermediate maximum value with respect to the sensitization maximum value of each dye, it is possible to use a combination of dyes having different maximum values.

Supersensitization-that is, a combination of spectral sensitizing dyes that result in spectral sensitization greater than that obtained from all concentrations of one dye alone or from the additive effect of a dye in a spectral region. Can be used. Supersensitization is a spectral sensitizing dye, a stabilizer and an antifoggant, a development accelerator or an inhibitor,
It can be achieved in selected combinations with other additives such as coating aids, optical brighteners and antistatic agents. One of several mechanisms and compounds that can cause color sensitization is described by Gilman in Photographic Science and E
ngineering, 18, 1974, pp. 418-430.

Spectral sensitizing dyes can also affect emulsions in other ways. For example, spectral sensitizing dyes can increase photographic sensitivity within the spectral region of intrinsic sensitivity. Brooker et al. U.S. Pat.No. 2,131,038, Illingsworth
Other U.S. Pat.No. 3,501,310, Webster et al. U.S. Pat.
630,749; U.S. Pat.No. 3,718,470 to Spence et al. And Shib.
a As disclosed in other U.S. Pat.No. 3,930,860,
Spectral sensitizing dyes can also function as antifoggants or stabilizers, development accelerators or inhibitors, reducing agents or nucleating agents, and halogen or electron acceptors.

Particularly useful photosensitizing dyes for sensitizing the emulsions of the present invention are British Patent No. 742,112; Brooker U.S. Pat.
No. 846,300, No. 1,846,301, No. 1,846,302, No.
Nos. 1,846,303; 1,846,304; 2,078,233 and 2,089,729; Brooker et al., U.S. Pat.
No. 2,213,238, No. 2,493,747, No. 2,493,74
No. 8, No. 2,526,632, No. 2,739,964 (Reissue No. 24,
No. 292), No. 2,778,823, No. 2,917,516, No. 3,3
No. 52,857, No. 3,411,916 and No. 3,431,111, Spra
gue U.S. Pat.No. 2,503,776; Nys et al. U.S. Pat.
No. 2,933, Riester U.S. Pat.No. 3,660,102, Kampfer et al. U.S. Pat.No. 3,660,103, Taber et al. U.S. Pat.
No. 010, No. 3,352,680 and No. 3,384,486, Lincoln
Other U.S. Pat.No. 3,397,981, Fumia et al. U.S. Pat.
Nos. 2,978 and 3,623,881, U.S. Pat.
No. 718,470 and Mee U.S. Pat. No. 4,025,349, the disclosures of which are incorporated herein by reference. Examples of useful supersensitizing dye combinations, non-light absorbing additives or useful dye combinations that function as supersensitizers include McFall et al. U.S. Pat.No. 2,933,390, Jones et al. U.S. Pat. No.Motter U.S. Pat.No. 3,506,4
No. 43 and U.S. Pat. No. 3,672,898 to Schwan et al., The disclosures of which are incorporated herein by reference.

The spectral sensitizing dye may be added at any stage during emulsion preparation. These are Wall, Photographic Emulsions, Americ
an Photographic Publishing Co., Boston, 1929, 65
Page, Hill U.S. Pat.No. 2,735,766, Philippaerts et al., U.S. Pat.No. 3,628,960, Locker U.S. Pat.
U.S. Pat.No. 4,225,666 to Locker et al., Research Disc.
losure, vol. 181 May 1979, Item 18155 and EP 301,508 to Tani et al. can be added at the beginning or during the beginning of precipitation. These are described in U.S. Pat.No. 4,439,520 to Kofron et al., Dickerson.
U.S. Pat.No. 4,520,098; Maskasky U.S. Pat.
It can be added before or during chemical sensitization as described in US Pat. No. 5,501 and Philippaerts et al. Cited above. These are published by Asami et al. In published European patent application EP 287,
No. 100 and published European patent application EP 291,39 by Metoki et al.
As described in No. 9, it can be added before or during emulsion washing. The dye is a U.S. patent to Collins et al.
It can be mixed immediately before application as described in 2,912,343. As described by Dickerson cited above, a small amount of iodide can be adsorbed on the emulsion grains to promote aggregation and adsorption of the spectral sensitizing dye. As described by Dickerson, post-processing dye stain can be reduced by the proximity of fine high iodide grains to the dyed emulsion layer. Depending on their solubility, spectral sensitizing dyes can be either water or a solution such as methanol, ethanol, acetone or pyridine dissolved in a surfactant solution as described in Sakai et al., U.S. Pat. U.S. Patent No.
As described in JP-A-3,469,987 and JP-B-46-24185, it can be added to the emulsion as a dispersion. Mi
As described in Fune et al., published European Patent Application EP 302,528, this dye selectively adsorbs to specific crystallographic surfaces of emulsion grains as a means of suppressing chemical sensitization centers to other surfaces. Can be done. Published European Patent Applications 270,079, 270,082 and 278,51 by Miyasaka et al.
As described in No. 0, spectral sensitizing dyes can be used with less adsorbed luminescent dyes.

 The following illustrates a particular spectral sensitizing dye selection.

SS-1 Anhydro-5'-chloro-3'-di- (3-sulfopropyl) naphtho [1,2-d] thiazolothiocyanin hydroxide, sodium salt SS-2 Anhydro-5'-chloro-3 ' -Di- (3-sulfopropyl) naphtho [1,2-d] oxazolothiocyanine
Hydroxide, sodium salt SS-3 Anhydro-4,5-benzo-3'-methyl-4'-phenyl-1- (3-sulfopropyl) naphtho [1,2-d]
Thiazolotiathiazolocyanine hydroxide SS-4 1,1'-Diethylnaphtho [1,2-d] thiazolo-2'-cyanine bromide SS-5 Anhydro-1,1'-dimethyl-5,5'-di- (Trifluoromethyl) -3- (4-sulfobutyl) -3 ′-(2,
2,2-trifluoroethyl) benzimidazolocarbocyanine hydroxide SS-6 anhydro-3,3 '-(2-methoxyethyl) -5,5'-
Diphenyl-9-ethyloxacarbocyanine, sodium salt SS-7 Anhydro-11-ethyl-1,1'-di- (3-sulfopropyl) naphtho [1,2-d] oxazolocabocyanine
Hydroxide, sodium salt SS-8 Anhydro-5,5'-dichloro-9-ethyl-3,3'-di- (3-sulfopropyl) oxaselenacarbocyanine hydroxide, sodium salt SS-9 5,6- Dichloro-3 ', 3'-dimethyl-1,1', 3-triethylbenzimidazolo-3H-indolocarbocyanine
Bromide SS-10 Anhydro-5,6-dichloro-1,1-diethyl-3- (3
-Sulfopropyl) benzimidazolooxacarbocyanine hydroxide SS-11 anhydro-5,5'-dichloro-9-ethyl-3,3'-di- (2-sulfoethylcarbamoylmethyl) thiacarbocyanine hydroxide, sodium Salt SS-12 Anhydro-5 ', 6'-dimethoxy-9-ethyl-5
Phenyl-3- (3-sulfobutyl) -3 '-(3-sulfopropyl) oxathiacarbocyanine hydroxide, sodium salt SS-13 Anhydro-5,5'-dichloro-9-ethyl-3- (3
-Phosphonopropyl) -3 '-(3-sulfopropyl)
Thiacarbocyanine hydroxide SS-14 Anhydro-3,3'-di- (2-carboxyethyl)-
5,5'-Dichloro-9-ethylthiacarbocyanine bromide SS-15 Anhydro-5,5'-dichloro-3- (2-carboxyethyl) -3 '-(3-sulfopropyl) thiacyanine sodium salt SS-16 9- (5-barbituric acid) -3,5-dimethyl-3'-
Ethyltellurate carbocyanine bromide SS-17 anhydro-5,6-methylenedioxy-9-ethyl-3
-Methyl-3 '-(3-sulfopropyl) tellurachiacarbocyanine hydroxide SS-18 3-Ethyl-6,6'-dimethyl-3'-pentyl-9,11
-Neopentylene lentiazicarbocyanine bromide SS-19 anhydro-3-ethyl-9,11-neopenthylene-3 '
-(3-sulfopropyl) thiadicarbocyanine hydroxide SS-20 anhydro-3-ethyl-11,13-neopenthylene-
3 '-(3-sulfopropyl) oxathiatricarbocyanine hydroxide, sodium salt SS-21 anhydro-5-chloro-9-ethyl-5'-phenyl-
3 '-(3-Sulfobutyl) 3- (3-sulfopropyl) oxacarbocyanine hydroxide, sodium salt SS-22 Anhydro-5,5'-diphenyl-3,3'-di- (3-sulfobutyl) -9 -Ethyloxacarbocyanine hydroxide, sodium salt SS-23 Anhydro-5,5'-dichloro-3,3'-di- (3-sulfopropyl) -9-ethylthiacarbocyanine hydroxide, triethylammonium salt SS- 24 Anhydro-5,5'-dimethyl-3,3'-di- (3-sulfopropyl) -9-ethylthiacarbocyanine hydroxide, sodium salt SS-25 Anhydro-5,6-dichloro-1-ethyl- 3- (3-
Sulfobutyl) -1 '-(3-sulfopropyl) benzimidazolonaphtho [1,2-d] thiazolocarbocyanine hydroxide, triethylammonium salt SS-26 anhydro-11-ethyl-1,1'-di- ( 3-sulfopropyl) naphtho [1,2-d] oxazolocarbocyanine hydroxide, sodium salt SS-27 Anhydro-3,9-diethyl-3'-methylsulfonylcarbamoylmethyl-5-phenyloxathiacarbocyanine p- Toluenesulfonate SS-28 Anhydro-6,6'-dichloro-1,1'-diethyl-3,
3'-di- (3-sulfopropyl) -5,5'-bis (trifluoromethyl) benzimidazolocarbocyanine hydroxide, sodium salt SS-29 anhydro-5'-chloro-5-phenyl-3,3 '-Di- (3-sulfopropyl) oxathiocyanine hydroxide, sodium salt SS-30 Anhydro-5,5'-dichloro-3,3'-di- (3-sulfopropyl) thiocyanine hydroxide, sodium salt SS -31 3-ethyl-5- [1,4-dihydro-1- (4-sulfobutyl) pyridine-4-ylidene] rhodanine, triethylammonium salt SS-32 1-carboxyethyl-5- [2- (3-ethyl Benzoxazoline-2-ylidene) ethylidene] -3-phenylthiohydantoin SS-33 4- [2-((1,4-dihydro-1-dodecylpyridine-ylidene) ethyl) Den] -3-phenyl-2-isoxazolin-5-one SS-34 5- (3-ethylbenzoxazolin-2-ylidene)-
3-phenylrhodanine SS-35 1,3-diethyl-5-{[1-ethyl-3- (3-sulfopropyl) benzimidazoline-2-ylidene] ethylidene} -2-thiobarbituric acid SS-365 -[2- (3-ethylbenzoxazoline-2-ylidene) ethylidene] -1-methyl-2-dimethylamino-
4-oxo-3-phenylimidazolinium p-toluenesulfonate SS-37 5- [2- (5-carboxy-3-methylbenzoxazoline-2-ylidene) ethylidene] -3-cyano-4-
Phenyl-1- (4-methylsulfonamido-3-pyrrolin-5-one SS-38 2- [4- (hexylsulfonamido) benzoylcyanomethine] -2- {2-} 3- (2-methoxyethyl)
-5-[(2-methoxyethyl) sulfonamido] benzoxazoline-2-ylidene {ethylidene} acetonitrile SS-39 3-methyl-4- [2- (3-ethyl-5,6-dimethylbenzotellrazolin-2-) Ilidene) ethylidene] -1
-Phenyl-2-pyrazolin-5-one SS-40 3-heptyl-1-phenyl-5- {4- [3- (3-
Sulfobutyl) -naphtho [1,2-d] thiazoline] -2
-Butenylidene} -2-thiohydantoin SS-41 1,4-phenylene-bis (2-aminovinyl-3-methyl-2-thiazolinium] dichloride SS-42 anhydro-4- {2- [3- (3-sulfo Propyl)
Thiazoline-2-ylidene] ethylidene {-2-} 3-
[3- (3-sulfopropyl) thiazoline-2-ylidene] propenyl-5-oxazolium hydroxide,
Sodium salt SS-43 3-carboxymethyl-5- {3-carboxymethyl-
4-oxo-5-methyl-1,3,4-thiadiazoline-2-
Ilidene) ethylidene] thiazoline-2-ylidene｝ rhodanine, dipotassium salt SS-44 1,3-diethyl-5- [1-methyl-2- (3,5-dimethylbenzotellrazolin-2-ylidene) ethylidene]-
2-thiobarbituric acid SS-45 3-methyl-4- [2- (3-ethyl-5,6-dimethylbenzotellrazolin-2-ylidene) -1-methylethylidene] -1-phenyl-2-pyrazoline -5-one SS-46 1,3-diethyl-5- [1-ethyl-2- (3-ethyl-5,6-dimethoxybenzotellrazolin-2-ylidene) ethylidene] -2-thiobarbituric acid SS -47 3-ethyl-5-{[(ethylbenzothiazoline-2-
Ilidene) -methyl]-[(1,5-dimethylnaphtho [1,2
-D] selenazoline-2-ylidene) methyl] methylene} rhodanine SS-48 5- {bis [(3-ethyl-5,6-dimethylbenzothiazoline-2-ylidene) methyl] methylene} -1,3-diethyl- Barbituric acid SS-49 3-Ethyl-5-{[(3-ethyl-5-methylbenzotellrazolin-2-ylidene) methyl] [1-ethylnaphtho [1,2-d] -tellrazolin-2-ylidene) Methyl] methylene｝ rhodanine SS-50 Anhydro-5,5'-diphenyl-3,3'-di- (3-sulfopropyl) thocyanine hydroxide, triethylammonium salt SS-51 Anhydro-5-chloro-5'-phenyl -3,3'-di- (3-sulfopropyl) thiacyanine hydroxide, triethylammonium salt A negative emulsion that does not increase the minimum density (i.e., fog) of the emulsion coating. Qualitative include stabilizers, antifoggants, kink inhibitor (antikinking agent), by incorporating in the emulsion and contiguous layers prior to applying the latent image stabilizers and similar additives,
Can be protected. CEKMees, The Theory of the
Photographic Process, Second Edition, Macmillan, 1954, 6
As shown on pages 77-680, most of the antifoggants effective in the emulsions of the present invention can also be used in developers and can be classified under a few general subjects. it can.

To avoid such instability in emulsion coatings, halide ions (eg, bromide salts), chloropalladates and chloroparadite as shown in US Pat. No. 2,566,263 to Trivelli et al. (Chloropalladites), water-soluble inorganic salts of magnesium, calcium, cadmium, cobalt, manganese and zinc as shown in Jones U.S. Pat. No. 2,839,405 and Sidebotham U.S. Pat. No. 3,488,709; Allen et al. U.S. Pat. Mercury salt, Bro, as indicated in the issue
selenols and diselenides as shown in wn et al., British Patent 1,336,570 and Pollet et al., British Patent 1,282,303; Allen et al., U.S. Patent 2,694,716; Brooke
r Other U.S. Pat.No. 2,121,038; Graham U.S. Pat.
U.S. Pat.No. 3,596,478; quaternary ammonium salts as shown in U.S. Pat.No. 3,954,478 to Arai et al .; azomethine desensitizing dyes as shown in U.S. Pat.No. 3,630,744 to Thiers et al .; U.S. Pat. No. 3,220,839 and U.S. Pat.No. 2,514,650 to Knott et al., Thiazolidine as shown in U.S. Pat.No. 3,565,625 to Scavron, and U.S. Pat. New peptide derivatives, pyrimidine and 3-pyrazolidone, as shown in Welsh U.S. Pat.No. 3,161,515 and Hood et al.
Azotriazole and azotetrazole as shown in U.S. Pat. No. 3,925,086 to ldassarri et al., Heimbach
U.S. Pat.No. 2,444,605; Knott U.S. Pat.
No. 8, Williams U.S. Pat.No. 3,202,512, Research Dis
closure, Volume 134, June 1975, Item 13452 and 148, 19
August 1 76, Item 14851 and Nepker et al., British Patent 1,338,
Azaindenes, such as those shown in No. 567, especially tetraazaindene, Kendall et al.Tokyo U.S. Pat.No. 2,403,927, Ke
nnard et al., U.S. Pat.No. 3,266,897, Research Disclosur
e, Volume 116, December 1973, Item 11684, Mercaptotetrazole, mercaptotriazole and mercaptodiazole, peterson, as shown in Luckey et al., U.S. Pat.
U.S. Pat.No. 2,271,229 and Research Did.
azole, S as shown in sclosure, Item 11684, S
U.S. Pat.No. 2,319,090 to Heppard et al., U.S. Pat.No. 2,152,460 to Birr et al., Research Disclosure, Item cited above.
Purine as shown in 13452 and Dostes et al., French Patent 2,296,204; 1,3-dihydroxy (and / or) as shown in Saleck et al., US Pat. No. 3,926,635.
Polymers of 1,3-carbamoxy) -2-methylenepropane, tellurazole, tellrazoline, tellrazolium and tellurazolium salts as shown in Gunther et al. U.S. Pat. No. 4,661,438, and Gunther U.S. Pat.
No. 81,330 and U.S. Pat.No. 4,661,43 to Przyklek-Elling et al.
Stabilizers and antifoggants such as the aromatic oxatellradinium salts shown in US Pat. No. 8,677,202 and US Pat. No. 4,677,202 can be used. High chloride emulsions are disclosed in Miyoshi et al., Published European Patent Application EP 294, especially during chemical sensitization.
No. 149 and published European patent application EP 297,80 by Tanaka et al.
Elemental sulfur as described in No. 4 and Nishikawa
It can be stabilized by the presence of thiosulphonates as described in other published European patent application EP 293 917.

A particularly useful stabilizer for gold sensitized emulsions is Yutzy
Water-soluble gold compounds of benzothiazole, benzoxazole, naphthothiazole and certain merocyanine and cyanine dyes as shown in other U.S. Pat.No. 2,597,915, and are shown in U.S. Pat. Such a sulfinamide.

Particularly useful stabilizers in layers containing poly (alkylene oxide) are described, inter alia, in Carroll et al., US Pat.
No. 6,062, British Patent No. 1,466,024 and Habu et al., U.S. Pat.No. 3,929,486, Group VIII noble metals or resorcinol derivatives, quaternary ammonium salts of the type shown in Piper U.S. Pat. Water-insoluble hydroxides as shown in U.S. Pat.No. 2,953,455 to Maffet; U.S. Pat.
Phenol, Dersch as shown in 2,955,038
Ethylene diurea as shown in U.S. Pat.
Boranes as shown in 3,725,078, 3-pyrazolidinones as shown in Wood's British Patent 1,158,059 and aldoximines, amides as shown in Butler et al. In British Patent 988,052. , Tetraazaindene in combination with anilides and esters.

This emulsion is a sulfocatechol-type compound, such as that shown in Kennard et al., U.S. Pat.
Additives such as aldoximine as shown in other U.S. Pat.No. 623,448 and meta- and polyphosphates as shown in Draisbach U.S. Pat. By containing ethylenediaminetetraacetic acid as described above, fog and desensitization caused by trace amounts of metals such as copper, lead, tin, iron and the like can be protected.

Particularly useful stabilizers in layers containing synthetic polymers of the type used as vehicles and for improving covering power are mono- and polyhydric phenols such as shown in Forsgard U.S. Pat.No. 3,043,697. , UK Patent 897,
No. 497 and the sugars as shown in Stevens et al., British Patent 1,039,471, and Dersch et al., U.S. Pat.
No. 8 quinoline derivatives.

Particularly useful stabilizers in protecting the emulsion layer against bicolor fog are the salts of nitrones, such as those shown in U.S. Patent Nos. 3,679,424 and 3,820,998 to Barbier et al.
Mercaptocarboxylic acids as shown in U.S. Pat. No. 3,600,178 to Illems et al. and Birr, "Stabilization of Photographic Silv.
er Halide Emulsion "), Focal Press, London, 1974
, Pages 126-218.

Particularly useful stabilizers in protecting the emulsion layer against development fog are Bloom et al., British Patent No. 1,356,142 and U.S. Pat.No. 3,575,699, Rogers U.S. Pat. Azabenzimidazoles as shown in Brooker et al., U.S. Pat.No. 2,131,038, Land U.S. Pat.
Substituted benzimidazoles, benzothioazoles, benzotriazoles and the like as shown in other U.S. Pat.
ch et al. U.S. Patent No. 3,081,170; Weyerts et al. U.S. Patent No.
Nos. 3,260,597, Grasshoff et al., U.S. Pat.No. 3,674,478 and Arond U.S. Pat. Urea derivatives, and U.S. Pat.No. 3,364,028 to von Konig and British Patent 1,186,441 to von Konig et al.
Additives such as thiodiazole derivatives as indicated in the article.

When an aldehyde type hardener is used, the emulsion is Shep
Monohydric and polyhydric phenols of the type shown in U.S. Pat.No. 2,165,421 to Pard et al.
Nitro-substituted compounds of the type shown in No. 8, poly (alkylene oxides) as shown in Valbusa British Patent 1,151,914 and U.S. Pat. No. 3,232,7
No. 3,295, U.S. Pat.No. 3,295,61 in combination with urazole as shown in U.S. Pat.
It can be protected with an antifoggant, such as mucohalic acid in combination with maleic hydrazide as shown in 980.

To protect emulsion layers coated on a linear polyester support, paravanic acid, hydantoic hydrazide and urazole as shown in Anderson et al. U.S. Pat.No. 3,287,135 and Rees et al. U.S. Pat.
Additives such as piazines containing two symmetrically fused six-membered carbocycles can be used, such as those indicated in US Pat.

Emulsion kink desensitization is described by Overman in U.S. Pat.
Thallium nitrate as indicated in US Pat. Nos. 2,759,821 and 2,759,822 to Jones et al., Polymer latexes and dispersions, Rese
Arch Disclosure, Vol. 116, December 1973, Azole and mercaptotetrazole hydrophilic colloid dispersions of the type disclosed in Item 11684, Milton et al., U.S. Pat.No. 3,033,
Plasticized gelatin compositions of the type disclosed in No. 680, R
by emulsion polymerization in the presence of a water-soluble interpolymer of the type disclosed in US Pat. No. 3,536,491 to Ees et al., poly (alkylene oxide) as disclosed in US Pat. No. 3,772,032 to Pearson et al. Polymer Latexes Made and Rakoczy U.S. Pat.
It can be reduced by including a gelatin graft copolymer of the type disclosed in U.S. Pat.

If the photographic element must be processed at elevated bath and drying temperatures, such as in a rapid access processor, pressure desensitization and / or increased fog can result from Abbott et al., US Pat. No. 3,295,976, Barnes Other U.S. Patent No. 3,545,9
No. 71, Salesin U.S. Pat.No. 3,708,303, Yamamoto et al. U.S. Pat.No. 3,615,619, Brown et al. U.S. Pat.
No. 3, Taber U.S. Pat.No. 3,671,258, Abele U.S. Pat.No. 3,791,830, Research Disclosure, Vol. 99, July 1972
Moon, Item 9930, Florens et al. U.S. Patent No. 3,843,364, P
As shown in U.S. Pat.No. 3,876,152 to riem et al., U.S. Pat.No. 3,967,965 to Adachi et al. and U.S. Pat.Nos. 3,947,274 and 3,954,474 to Mikawa et al.
It can be controlled by a selected combination of vehicle, hardener and / or development conditions.

In addition to raising the pH or lowering the pAg of the emulsion and adding gelatin, which are known to delay latent image regression, Ezekiel GB 1,335,923, U.S. Pat.
Nos. 1,378,354, 1,387,654 and 1,391,672, E
British Patent 1,394,371 to zekiel et al., U.S. Patent 3,843,372 to Jefferson, British Patent 1,412,294 to Jefferson et al.
Carbonyl-bisulfite addition in combination with amino acids such as those shown in U.S. Pat.No. 1,343,904 to Thurston, hydroxybenzene or aromatic amine developing agents as shown in U.S. Pat. Products, cycloalkyl-1,3 diones as shown in U.S. Pat.No. 3,447,926 to Beckett et al., Enzymes of catalase type as shown in U.S. Pat.No. 3,600,182 to Matejec et al., U.S. Pat. Halogen-substituted hardeners in combination with certain cyanine dyes as shown in U.S. Pat.No. 3,881,933, hydrazides as shown in Honig et al. U.S. Pat.No. 3,386,831, U.S. Pat. 95
Alkenyl benzothiazolium salts as shown in U.S. Pat. No. 4,478, Thurston's British Patent 1,308,777 and Ezeki
el et al., Hydroxy-substituted benzylidene derivatives as shown in British Patent Nos. 1,347,544 and 1,353,527;
Mercapto-substituted compounds of the type disclosed in Sutherns U.S. Pat.No. 3,519,427; Matejec et al. U.S. Pat.
Ezek, a metal-organic complex of the type disclosed in US Pat.
penicillin derivatives as shown in U.S. Pat. , 90
Combinations of iridium and rhodium compounds as disclosed in U.S. Pat.
Sidnone or sydnonimine as shown in No. 9, thiazolidine derivatives as shown in Ezekiel British Patent No. 1458,197 and Research Disclosure, 13
Latent image stabilizers can be included, such as thioether-substituted imidazoles as shown in Volume 6, August 1975, Item 13651.

Apart from the features specifically mentioned, the tabular grain emulsion making process, the tabular grains made by this process and further use in photography can take any convenient conventional form. It is generally intended to replace conventional emulsions with the same or similar silver halide compositions, and that replacing silver halide emulsions with different silver halide compositions, especially tabular grain emulsions, is not an option. It is feasible in applications. The low level of native blue sensitivity of the high chloride {100} tabular grain emulsions of this invention is due to both the layer ordering of photographic elements containing tabular grain emulsions and other conventional features, as described by Kofron et al. To enable the emulsion to be used in all desired layer order arrangements of a multicolor photographic element, including all layer order arrangements disclosed in U.S. Pat. No. 4,439,520, the disclosure of which is incorporated herein by reference. I do. The conventional configuration is
This is further illustrated by the disclosure below, which is incorporated by reference.

ICBR-1 Research Disclosure, Volume 308, December 1989
Mon, Item 308, 119; ICBR-2 Research Disclosure, Vol. 225, January 1983
Moon, Item 22,534; ICBR-3 Wey et al., U.S. Patent No. 4,414,306, November 1983.
Issued on August 8; ICBR-4 Solberg et al., U.S. Pat. No. 4,433,048, 1984
Issued February 21, 1993; ICBR-5 Wilgus et al., U.S. Pat. No. 4,434,226, 1984.
Issued February 28, 1980; ICBR-6 Maskasky U.S. Pat. No. 4,435,501, 1984
Issued March 6, 1987; ICBR-7 Maskasky, U.S. Pat. No. 4,643,966, 1987
Issued February 17, 1998; ICBR-8 Daubendiek et al., US Pat. No. 4,672,027, 1
Issued Jan. 9, 987; ICBR-9 Daubendiek et al., U.S. Pat. No. 4,693,964, 1
Published September 15, 987; ICBR-10 Maskasky U.S. Pat. No. 4,713,320, 1987
Issued December 15, 1998; ICBR-11 Saitou et al., U.S. Patent No. 4,797,354, 1989.
Issued January 10, 2001; ICBR-12 Ikeda et al., U.S. Patent No. 4,806,461, issued February 21, 1989; ICBR-13 Makino et al., U.S. Patent No. 4,853,322, 1989.
Issued August 1, 1998; ICBR-14 Daubendiek et al., US Pat. No. 4,914,014, 1
Published April 3, 990; photographic elements containing high chloride {100} tabular grain emulsions prepared according to the present invention were prepared in the ultraviolet and visible (eg, actinic) and infrared regions of the electromagnetic spectrum, and electron beam. And beta radiation, gamma rays, X-rays, alpha particles,
Imagewise exposure to neutrons and various forms of energy, including particles in either the incoherent (random phase) form or the interfering (in phase) form as produced by lasers and other forms of wavy radiant energy Can be. The exposure can be monochromatic, orthochromatic or panchromatic. THJames, Photo Processing Theory (The The
ory of the Photographic Process), 4th edition, Macmill
an, 1977, as indicated in Chapters 4, 4, 6, 17, 18 and 23, high or low intensity exposure, continuous or intermittent exposure, ranging from minutes to relatively short duration in the millisecond to microsecond range. Using ambient, imagewise exposure at high and low temperatures and / or pressures, including exposure times and solarizing exposure, within useful response ranges determined by conventional sensitometric techniques Can be.

Examples The invention can be better appreciated by reference to the following examples. In the following example, the acronym AP
MT is used to refer to 1- (3-acetamidophenyl) -5-mercaptotetrazole. The term "low methionine gelatin," unless otherwise indicated, is used to refer to gelatin that has been treated with an oxidizing agent to reduce its methionine content to less than 30 micromol / g. The acronym DW is used to indicate distilled water. Acronym mp
pm is used to indicate parts per million, while ppm is used to indicate parts per million on a weight basis. The term "Rsens"
Is used in some examples to indicate relative sensitivity.

Examples 1 and 2 These examples use a dual zone growth method in which the growth reactants are premixed in a continuous reactor before addition to the growth reactor to produce tabular grains having an ECD greater than 2 μm. Production of an emulsion satisfying the requirements of the present invention will be described.

Example 1 A stirred reaction vessel containing 1.77 wt% bone gelatin, 0.0056 M sodium chloride, 1.86 × 10 ⁻⁴ M potassium iodide and 2945 mL of a solution at 55 ° C. and pH 6.5, 15 mL of 4.0 M silver nitrate solution and 4.0 15 mL of M sodium chloride solution were each added simultaneously at a rate of 30 mL / min.

The mixture was then held for 5 minutes while adding 7000 mL of distilled water and raising the temperature to 65 ° C., while adjusting the pCl to 2.15 and the pH to 6.5. Following this hold, the size of the resulting particles was increased through growth using a dual zone method. In this method, a solution of 0.67M silver nitrate was premixed with a 0.67M solution of sodium chloride and a solution of 0.5% by weight bone gelatin at pH 6.5 in a continuous reactor with a total volume of 30 mL and mixed well. . The effluent from this premix reactor was then added to the first reaction vessel that served as the growth reactor during this step. During the growth step, the microcrystals from the continuous reactor were aged on the first crystal by Ostwald ripening. The total suspension volume in the growth reactor during this growth step was kept constant at 13.5 L using ultrafiltration.

The flow rates of the 0.67 M silver nitrate solution and the 0.67 M sodium chloride solution were increased from 20 mL / min to 80 mL / min, 150 mL / min and 240 m at 25-minute intervals.
Increased linearly to L / min. The flow rate of the 0.5% gelatin reactant was kept constant at 500 mL / min. A continuous reactor premixed with these reagents was maintained at 30 ° C. and 2.45 pCl, while the growth reactor was maintained at a temperature of 65 ° C., 2.15 pCl and 6.5 pC.
PH was maintained.

In this manner, 6 moles of high aspect ratio tabular grain iodochloride emulsion containing 0.01 mole percent iodide was obtained. More than 90% of the total projected grain area was provided by tabular grains having {100} major faces, an average ECD of 2.55 μm and an average thickness of 0.165 μm. Thus, the tabular grain population had an average aspect ratio of 15.5 and an average tabularity of 93.7.

Example 2 In a 30 mL well-stirred continuous reactor, a 0.447 M silver nitrate solution (100 mL / min) was mixed with a 0.487 M sodium chloride and 0.00377 M potassium iodide solution (100 mL / min) and a 2.0 wt% bone gelatin solution (1 / min). ) With a pCl of 2.3 and a temperature of 40 ° C. to form silver iodochloride nuclei. The resulting mixture containing the nuclei is placed in a stirred semi-batch reactor for 1.5
Minutes. The semi-batch reactor was maintained at 65 ° C. and a constant volume of 13.5 L (using ultrafiltration), initially 2.15
PCl, a pH of 6.5 and a bone gelatin concentration of 0.37% by weight. During the nuclear transfer from the continuous reactor to the semi-batch reactor, the latter pCl was maintained at 2.15 by adding 1M sodium chloride solution.

After holding for 5 minutes, initial nucleus growth was performed by the dual zone method as described below. A solution of 0.67M silver nitrate, a solution of 0.67M sodium chloride and a solution of 0.5% by weight bone gelatin at a pH of 6.5 were premixed in a 30 mL continuous reactor and then transferred to a semi-batch reactor. Crystals from the continuous reactor were dissolved in the semi-batch reactor and the first nuclei grew by Ostwald ripening of increasing size. The total suspension volume of the semi-batch reactor was kept constant at 13.5 L during this step as well as during the nucleation step.

During the growth step, the flow rates of the 0.67 M silver nitrate solution and the 0.67 M sodium chloride solution were increased from 20 mL / min to 80 mL / min at 25-minute intervals, 150 m
It was increased linearly to L / min and 240 mL / min. The flow rate of the 0.5% gelatin reactant was kept constant at 500 mL / min. A continuous reactor premixed with these reactants was placed at 30 ° C and 2.45 ° C.
maintained at pCl, while the growth reactor was maintained at a temperature of 65 ° C. and a p of 2.15.
Cl and a pH of 6.5 were maintained.

In this manner, 6 moles of a large high aspect ratio tabular grain iodochloride emulsion containing 0.01 mole percent iodide was obtained. For more than 80% of total projected grain area, {100} major surface, 2.28μ
It was tolerated by tabular grains having an average ECD of m and an average thickness of 0.195 μm. So this tabular grain population
It had an average aspect ratio of 11.7 and an average tabularity of 60.0.

Example 3 This example illustrates the preparation of an ultrathin tabular grain silver iodochloride emulsion satisfying the requirements of the present invention.

2030 mL of a solution containing 1.75 wt% low methionine gelatin, 0.011 M sodium chloride and 1.48 × 10 ⁻⁴ M potassium iodide was prepared in a stirred reaction vessel. The contents of the reaction vessel were maintained at 40 ° C. and the pCl was 1.95.

While stirring this solution vigorously, 30 mL of 1.0 M silver nitrate solution
And 30 mL of 0.99 M sodium chloride and 0.01 M potassium iodide solutions were added simultaneously at a rate of 30 mL / min each.
This resulted in nucleation, producing crystals having an initial iodide concentration of 2 mol%, based on total silver.

The mixture was then held at a temperature that remained at 40 ° C. for 10 minutes. Following this hold, then a 1.0 M silver nitrate solution and 1.0 M
The sodium chloride solution was maintained at 2 mL /
At the same time for 40 minutes.

The resulting emulsion was a tabular grain silver iodochloride emulsion containing 0.5 mole percent iodide, based on silver. Of the total grain projected area
50% is an average of 0.84 μm, selected based on the aspect ratio ranking of all {100} tabular grains having a thickness of less than 0.3 μm and a major surface edge length ratio of less than 10.
Provided by ECD and tabular grains having {100} major faces with an average thickness of 0.037 μm. The selected tabular grain population had an average aspect ratio (ECD / t) of 23 and an average tabularity (ECD / t ² ) of 657. The ratio of the major surface edge length of the selected tabular grains was 1.4. 72% of the total grain projected area was composed of tabular grains having {100} major faces and an aspect ratio of at least 7.5. These tabular grains had an average ECD of 0.75 μm, an average thickness of 0.045 μm, an average aspect ratio of 18.6 and an average tabularity of 488.

 A representative sample of the grains of this emulsion is shown in FIG.

Example 4 (Comparative) This emulsion demonstrates the importance of iodide in the precipitation of the initial grain population (nucleation).

This emulsion was precipitated as in Example 1 except that no iodide was intentionally added.

The obtained emulsion mainly has an edge length of about 0.1 to 0.5 μm.
And a rectangular particle having a very small aspect ratio. There were a few large rods and high aspect ratio {100} tabular grains,
It did not constitute a useful amount of the particle population.

 A representative sample of the grains of this emulsion is shown in FIG.

Example 5 This example shows that 90% of the total grain projected area is {100} major surface and
1 shows an emulsion according to the invention consisting of tabular grains having an aspect ratio greater than 7.5.

2030 mL of a solution containing 3.52 wt% low methionine gelatin, 0.0056 M sodium chloride and 148 × 10 ⁻⁴ M potassium iodide was prepared in a stirred reaction vessel. The contents of the reaction vessel were maintained at 40 ° C. and the pCl was 2.25.

While stirring this solution vigorously, 30 mL of 2.0 M silver nitrate solution
And 30 mL of a 1.99 M sodium chloride and 0.01 M potassium iodide solution were added simultaneously at a rate of 60 mL / min each.
This resulted in nucleation, producing crystals having an initial iodide concentration of 1 mol%, based on total silver.

The mixture was then held at a temperature that remained at 40 ° C. for 10 minutes. Following this hold, then 0.5M silver nitrate solution and 0.5M
The sodium chloride solution was added at 8 mL /
At the same time for 40 minutes. Then, 0.5M silver nitrate solution and 0.5M sodium chloride solution were added to pCl in a linearly increasing flow from 8 mL / min to 16 mL / min in a linearly increasing flow over 130 min.
It was added simultaneously while maintaining at 35.

The resulting emulsion was a tabular grain silver iodochloride emulsion containing 0.06 mol% iodide, based on silver. Of the total grain projected area
50% is an average of 1.86 μm, selected based on the aspect ratio ranking of all {100} tabular grains having a thickness of less than 0.3 μm and a major surface edge length ratio of less than 10.
Provided by ECD and tabular grains having {100} major faces with an average thickness of 0.082 μm. The selected tabular grain population had an average aspect ratio (ECD / t) of 24 and an average tabularity (ECD / t ² ) of 314. The major surface edge length ratio of the selected tabular grains was 1.2. 93% of the total grain projected area was composed of tabular grains having {100} major faces and an aspect ratio of at least 7.5. These tabular grains had an average ECD of 1.47 μm, an average thickness of 0.086 μm, an average aspect ratio of 17.5 and an average tabularity of 222.

Example 6 This example shows an emulsion prepared in the same manner as the emulsion of Example 3 except that the initial iodide was 0.08 mol% and the final iodide was 0.04 mol%.

2030 mL of a solution containing 3.52 wt% low methionine gelatin, 0.0056 M sodium chloride and 3.00 × 10 ⁻⁵ M potassium iodide was prepared in a stirred reaction vessel. The contents of the reaction vessel were maintained at 40 ° C. and the pCl was 2.25.

While stirring this solution vigorously, 30 mL of 5.0 M silver nitrate solution
And 30 mL of 4.998 M sodium chloride and 0.002 M potassium iodide solutions were added simultaneously at a rate of 60 mL / min each. As a result, nucleation takes place, and 0.08 mol% based on total silver
A crystal having an initial iodide concentration of

The mixture was then held at a temperature that remained at 40 ° C. for 10 minutes. Following this hold, then 0.5M silver nitrate solution and 0.5M
The sodium chloride solution was added at 8 mL /
At the same time for 40 minutes.

The resulting emulsion was a tabular grain silver iodochloride emulsion containing 0.04 mole percent iodide, based on silver. Of the total grain projected area
50% is an average of 0.67 μm selected based on the aspect ratio ranking of all {100} tabular grains having a thickness of less than 0.3 μm and a major surface edge length ratio of less than 10.
Provided by tabular grains having an ECD and {100} major faces with an average thickness of 0.035 μm. The selected tabular grain population had an average aspect ratio (ECD / t) of 20 and an average tabularity (ECD / t ² ) of 651. The major surface edge length ratio of the selected tabular grains was 1.9. 52% of the total grain projected area was composed of tabular grains having {100} major faces and an aspect ratio of at least 7.5. These tabular grains had an average ECD of 0.63 μm, an average thickness of 0.036 μm, an average aspect ratio of 18.5 and an average tabularity of 595.

Example 7 This example shows an emulsion in which the initial grain population contains 6.0 mol% iodide and the final emulsion contains 1.6 mol% iodide.

2030 mL of a solution containing 3.52 wt% low methionine gelatin, 0.0056 M sodium chloride and 3.00 × 10 ⁻⁵ M potassium iodide was prepared in a stirred reaction vessel. The contents of the reaction vessel were maintained at 40 ° C. and the pCl was 2.25.

While stirring this solution vigorously, 30 mL of 1.0 M silver nitrate solution
And 30 mL of 0.97 M sodium chloride and 0.03 M potassium iodide solution were added simultaneously at a rate of 60 mL / min each.
This resulted in nucleation, yielding crystals having an initial iodide concentration of 6.0 mol%, based on total silver.

The mixture was then held at a temperature that remained at 40 ° C. for 10 minutes. Following this hold, then a 1.00 M silver nitrate solution and 1.0
2 mL of 0 M sodium chloride solution while maintaining pCl at 2.35
/ Min at the same time for 40 minutes.

The resulting emulsion was a tabular grain silver iodochloride emulsion containing 1.6 mole percent iodide, based on silver. Of the total grain projected area
50% is an average of 0.57 μm selected based on the aspect ratio ranking of all {100} tabular grains having a thickness of less than 0.3 μm and a major surface edge length ratio of less than 10.
Provided by ECD and tabular grains having {100} major faces with an average thickness of 0.036 μm. The selected tabular grain population had an average aspect ratio (ECD / t) of 16.2 and an average tabularity (ECD / t ² ) of 494. The major surface edge length ratio of the selected tabular grains was 1.9. 62% of the total grain projected area was composed of tabular grains having {100} major faces and an aspect ratio of at least 7.5. These tabular grains had an average ECD of 0.55 μm, an average thickness of 0.041 μm, an average aspect ratio of 14.5 and an average tabularity of 421.

Example 8 This example demonstrates that 2 mol% iodide is present in the initial population,
Add additional iodide during growth to final iodide level 5
The ultra-thin high aspect ratio {100} tabular grain emulsion in mol% is shown.

2030 mL of a solution containing 1.75 wt% low methionine gelatin, 0.0056 M sodium chloride and 1.48 × 10 ⁻⁴ M potassium iodide was prepared in a stirred reaction vessel. The contents of the reaction vessel were maintained at 40 ° C. and the pCl was 2.2.

While stirring this solution vigorously, 30 mL of 1.0 M silver nitrate solution
And 30 mL of 0.99 M sodium chloride and 0.01 M potassium iodide solutions were added simultaneously at a rate of 90 mL / min each.
This resulted in nucleation, producing crystals having an initial iodide concentration of 2 mol%, based on total silver.

The mixture was then held at a temperature that remained at 40 ° C. for 10 minutes. Following this hold, then a 1.00 M silver nitrate solution and 1.0
A 0 M sodium chloride solution was added simultaneously at 8 mL / min for 10 minutes while maintaining pCl at 2.35 while simultaneously adding 3.375 × 10 ⁻² M potassium iodide at 14.6 mL / min.

The resulting emulsion was a tabular grain silver iodochloride emulsion containing 5 mol% iodide, based on silver. 50 of total grain projected area
% Is an average EC of 0.58 μm, selected based on the aspect ratio ranking of all {100} tabular grains having a thickness of less than 0.3 μm and a major face edge length ratio of less than 10.
D and given by tabular grains having {100} major faces with an average thickness of 0.030 μm. The selected tabular grain population had an average aspect ratio (ECD / t) of 20.6 and an average tabularity (ECD / t ² ) of 803. The ratio of the main surface edge length of the selected tabular grains was 2. Of the total grain projected area
87% were composed of tabular grains having {100} major faces and an aspect ratio of at least 7.5. These tabular grains are
It had an average ECD of 0.54 μm, an average thickness of 0.033 μm, an average aspect ratio of 17.9 and an average tabularity of 803.

Example 9 This example demonstrates that 1 mol% iodide was present in the initial grain population, 50 mol% bromide was added during growth, and the final emulsion was 0.3 mol% iodide, 36 mol% bromide and 63.7 mol% bromide. The high aspect ratio {100} tabular grain emulsion converted to mol% chloride is shown.

2030 mL of a solution containing 3.52 wt% low methionine gelatin, 0.0056 M sodium chloride and 1.48 × 10 ⁻⁴ M potassium iodide was prepared in a stirred reaction vessel. The contents of the reaction vessel were maintained at 40 ° C. and the pCl was 2.25.

While stirring this solution vigorously, 30 mL of 1.0 M silver nitrate solution
And 30 mL of 0.99 M sodium chloride and 0.01 M potassium iodide solutions were added simultaneously at a rate of 60 mL / min each.
This resulted in nucleation.

The mixture was then held at a temperature that remained at 40 ° C. for 10 minutes. Following this hold, then 0.5M silver nitrate solution as well as 0.
25 M sodium chloride and 0.25 M sodium bromide solution, pC
Simultaneous addition at 8 mL / min for 40 minutes, maintaining l at 2.60, produced crystals having an initial iodide concentration of 2 mol%, based on total silver.

The resulting emulsion was a tabular grain silver iodochloride emulsion containing 0.27 mole percent iodide and 36 mole percent bromide, based on silver, with the balance being chloride. 50% of the total grain projected area is 0.3μ
0.4 μm average ECD and 0.032 μm, selected based on the aspect ratio ranking of all {100} tabular grains having thicknesses less than m and major surface edge length ratios less than 10.
given by tabular grains having {100} major faces with an average thickness of m. The selected tabular grain population had an average aspect ratio (ECD / t) of 12.8 and an average tabularity (ECD / t
t ² ). The major surface edge length ratio of the selected tabular grains was 1.9. 71% of the total grain projected area is $ 10
It was composed of tabular grains having a 0 ° major surface and an aspect ratio of at least 7.5. These tabular grains had an average ECD of 0.38 μm, an average thickness of 0.034 μm, an average aspect ratio of 11.3 and an average tabularity of 363.

Example 10 This example illustrates the preparation of an emulsion satisfying the requirements of the present invention using phthalated gelatin as a peptizer.

At 40 ° C., 6.0 mL of a 0.1 M aqueous silver nitrate solution and 0.11 M of a 0.1 M silver nitrate solution were placed in a stirred reaction vessel containing 310 mL of a solution containing 1.0% by weight of phthalated gelatin, 0.0063 M sodium chloride, and 3.1 × 10 ⁻⁴ M potassium iodide. 6.0 mL of sodium chloride solution was added simultaneously at a rate of 6 mL / min each.

The mixture was then held at a temperature that remained at 40 ° C. for 10 minutes. Following this hold, the silver and salt solutions were added for 15 minutes.
The mixture was added simultaneously while maintaining the pCl at 2.7 at a linearly accelerated flow from 3.0 mL / min to 9.0 mL / min.

The resulting emulsion was a high aspect ratio tabular grain silver iodochloride emulsion. 50% of the total grain projected area is 0.37 μm, selected based on the aspect ratio ranking of all {100} tabular grains having a thickness of less than 0.3 μm and a major surface edge length ratio of less than 10. Provided by tabular grains having {100} major faces with average ECD and average thickness of 0.037 μm. The selected tabular grain population had an average aspect ratio (ECD / t) of 10 and an average tabularity (ECD / t ² ) of 330. 70% of the total grain projected area was composed of tabular grains having {100} major faces and an aspect ratio of at least 7.5. These tabular grains have an average ECD of 0.3 μm, 0.04 μm.
m and an average tabularity of 210.

Electron diffraction studies of the square and rectangular surfaces of the tabular grains confirmed the principal plane {100} crystallographic orientation.

Example 11 This example illustrates the preparation of an emulsion satisfying the requirements of the present invention using native bone gelatin as a peptizer.

At 55 ° C. and pH 6.5, 0.69% by weight bone gelatin, 0.0056M
In a stirred reaction vessel containing 2910 mL of a solution of sodium chloride and 1.86 × 10 ⁻⁴ M potassium iodide, 60 mL of a 4.0 M silver nitrate aqueous solution and 60.0 mL of a 4.0 M sodium chloride solution were simultaneously added at a rate of 120 mL / min. Was added.

The mixture was then held for 5 minutes, during which time a 16.6 g / L low methionine gelatin, 5000 mL solution, was added to bring the pH to 6.
Adjusted to 5 and pCl to 2.25. Following this hold, the silver and salt solutions were added simultaneously at a linearly accelerated flow from 10 mL / min to 25.8 mL / min over a 63 minute period, maintaining the pCl of the mixture at 2.25.

The resulting emulsion was a high aspect ratio tabular grain silver iodochloride emulsion containing 0.01 mol% iodide. About 65% of the total projected grain area was provided by tabular grains having an average diameter of 1.5 μm and a thickness of 0.18 μm.

Example 12 This example compares the photographic performance of a {100} silver chloride tabular emulsion according to the present invention to a silver chloride cubic grain emulsion of similar average grain volume.

Emulsion A. Silver iodochloride tabular emulsion having {100} major faces Precipitation (reproducing emulsion 3 which was scaled up 3 times Example 3) 3.52% by weight of low methionine gelatin, 0.0056M sodium chloride and 1.48 × 10 ^-4 6090 mL of a solution containing M potassium iodide was prepared at 40 ° C. in a stirred reaction vessel. While stirring this solution vigorously, 90 mL of 2.0 M silver nitrate and 1.99 M sodium chloride and 0.01 M potassium iodide solution
90 mL were added simultaneously at a rate of 180 mL / min each. The mixture was then held at a temperature that remained at 40 ° C. for 10 minutes.
Following this hold, the 0.5M silver nitrate and 0.5M sodium chloride solutions were then accelerated linearly from 24 mL / min to 48 mL / min for 30 min at 24 mL / min, followed by 130 min, while maintaining pCl at 2.35. And added simultaneously. The pCl was then adjusted to 1.30 with sodium chloride, then 2.0 ml using ultrafiltration.
Of pCl, and then add 1.65 pCl with sodium chloride.
Was adjusted to. The resulting emulsion contains 0.06 mol% iodide, has an average equivalent circular grain diameter of 1.45 μm and 0.13 μm
Was a tabular grain silver chloride emulsion having an average grain thickness of

Sensitization A number of small-scale finishing experiments with varying levels of sensitizing dyes, sodium thiosulfate pentahydrate and diautanous dithiosulfate dihydrate, and retention times at 65 ° C, yielded optimal green light. Sensitization was found for Emulsion A. The optimum finish was as follows. 0.800 mmol / mol of green photosensitizing dye A was added to 0.5 mol part of emulsion A, which was melted at 40 ° C. and stirred well, and then kept for 20 minutes. 0.10mg /
Mole sodium thiosulfate pentahydrate and 0.20 mg / mol sodium aurous sodium dithiosulfate dihydrate
dithiosulfate dihydrate). The temperature was then raised to 65 ° C. over 9 minutes, then held at 65 ° C. for 4 minutes and rapidly cooled to 40 ° C.

Sensitizing dye A Emulsion B. Silver chloride cubic grain emulsion (control) Precipitation Monodispersed silver chloride cubic with a cubic edge length of 0.59 μm was added to 8.2 g / L sodium chloride, 28.2 g / L bone gelatin and 0.212 g / L 1 Prepared by simultaneous addition of 3.75 M silver nitrate and 3.75 M sodium chloride to a well-stirred solution containing, 8-dithiadioctanediol, maintaining the temperature at 68.3 ° C. and the pCl at 1.0. Temperature up to 40 ° C
And the emulsion was washed to 2.0 pCl by ultrafiltration and then adjusted to 1.65 pCl with sodium chloride.

Sensitization Optimal green light sensitization was found in the same manner as described for Emulsion A. The conditions for optimization were as follows. Emulsion B, which was melted at 40 ° C. in 0.05 mol amount and stirred well,
0.2 mmol / mol of sensitizing dye A was added and then held for 20 minutes. To this was added 0.25 mg / mol of sodium thiosulfate pentahydrate and 0.50 mg / mol of sodium gold (I) dithiosulfate dihydrate. The temperature is then raised to 65 over 9 minutes.
C., then held for 10 minutes and rapidly cooled to 40.degree.

Photographic performance Each of the sensitized emulsions is used as an anti-halation support,
Coated with 0.85 g / m ² silver with 1.1 g / m ² cyan dye-forming coupler C and 2.7 g / m ² gelatin. 1.6 g / m ²
Overcoated with gelatin, 1.7% based on total gelatin
Cured with wt% bis (vinylsulfonylmethyl) ether. The coating film is a mercury vapor lamp 365nm as a light source
Lines were evaluated for intrinsic sensitivity by exposing for 0.02 seconds in a step wedge sensitometer. Sensitivity to green light is determined by filtering to simulate a daylight V light source and transmitting only green and red light through a Kodak Wratten ^™ 9 filter (transmitting wavelengths longer than 450 nm). The exposure was measured by exposing the coatings for 0.02 seconds using a step wedge sensitometer with a 3000 K tungsten lamp filtered through.
The coating film is made of Kodak Flexic Color (Kodak Flexic Color) described in Brit. J. Photog. Annual 1988, pp. 196-198.
olor) The development was performed using the ^TM C-41 color negative development method and the dye density was measured using Status M red filtration.

Coupler C The photographic results are summarized in Table I.

Table I shows that for intrinsic sensitivities measured by 365 line exposure, both Emulsion A and Emulsion B are very similar, as would be expected to be based on their similar grain volumes. ing. Comparison of green light sensitivity as measured by Wratten ^™ 9 exposure shows that tabular emulsions are 2.9 times more sensitive to green light than cubic emulsions. This clearly shows the advantage of the flat configuration.

Example 13 This example was sensitized using gold sulfide and a blue spectral sensitizing dye and compared with a low silver coating on a resin coated paper support.
The sensitization and photographic performance of a 0 ° silver chloride tabular emulsion and a silver chloride cubic emulsion of similar average grain volume are described.

Precipitation of a silver chloride tabular emulsion having {100} major faces. This emulsion was prepared in the same manner as the {100} silver chloride tabular emulsion described in Example 10.

Precipitation of a silver chloride cubic emulsion This emulsion was the same as the cubic emulsion described in Example 10 except that the ripening agent 1,8-dithiadioctanediol was omitted and the flow rate and precipitation time were adjusted to obtain an emulsion of the same size. Manufactured in the same manner.

Sensitization Both emulsions were sensitized to blue light using the following method. A certain amount of each emulsion was melted at 40 ° C, and 660 mg / mol Ag of sensitizing dye B was added to {100} tabular emulsion based on their specific surface area, and 220 mg / mol of the same dye was added to cubic emulsion. And then held for 20 minutes. 2.0 mg / mol of gold sulfide was added to each emulsion and then held for 5 minutes. Then raise the temperature to 60
C. and hold for 30 minutes, then 90 mg / mol APMT
Was added and the emulsion was cooled and solidified.

Photographic performance Each of the sensitized emulsions was applied on a resin-coated paper support at 1.1 g / m
It was coated with silver 0.28 g / m ² with ² of the yellow dye-forming coupler B and 0.82 g / m ² gelatin. The coatings were evaluated for inherent sensitivity by exposing the coatings to a 365 nm line of a mercury vapor lamp as a light source in a step wedge sensitometer for 0.1 seconds. The sensitivity to white light was measured by exposing the coatings for 0.1 second with a 3000 ° K tungsten lamp using a step wedge sensitometer. The coating film is Research Disclosure, vol. 308, p. 933, 1989
Developed using the standard RA-4 color photographic paper development method described in the year. Standard reflection form and status A
Dye concentration was measured using filtration.

 The photographic results are summarized in Table II.

Table II shows that, for the inherent sensitivities measured by 365-line exposure, both the cubic and tabular emulsions have very similar sensitivities as would be expected based on these similar grain volumes. It is shown. Comparing white light sensitivity as measured by 3000 ° K tungsten exposure, tabular emulsions are about 50 times more blue light than cubic emulsions.
It shows that the% sensitivity is high.

Example 14 This example shows how bromide can be added at the end of precipitation or during finishing and / or growth to produce an emulsion having a surface halide structure. These emulsions show good photographic performance.

Emulsion A (Invention of the Invention) This emulsion was prepared in the same manner as the {100} tabular emulsion described in Example 10. An amount of this emulsion was then melted at 40 ° C. and 1200 mg / mol of potassium bromide was added rapidly.
Then 0.6 mmol of green sensitizing dye A per mole of emulsion was added and then held for 20 minutes. Then 1.0 mg / mol sodium thiosulfate pentahydrate and 1.3 mg / mol potassium tetrachloroaurate were added, then the temperature was raised to 60 ° C. and held for 10 minutes. The emulsion was then cooled to 40 ° C.
mg / mol of APMT was added and the emulsion was cooled and solidified. Examination of the crystals by scanning electron microscopy showed that the edges of the crystals were roughened by bromide deposition and that some surface roughening was also present.

Emulsion B (invention of the invention) This emulsion was prepared by adding potassium bromide during the final step of precipitation to form an emulsion, whereby the majority of the grains had three or four of the four available tabular grain corners. 9 shows the precipitation and sensitization of a {100} silver chloride tabular emulsion with epitaxy deposits arranged in four.

Precipitation 1536 mL of a solution containing 3.52% by weight of low methionine gelatin, 0.0056 M sodium chloride and 2.34 × 10 ⁻⁴ M potassium iodide was placed in a stirred reaction vessel at 40 ° C. and pH 5.74.
Manufactured by. While vigorously stirring this solution, 30 mL of 2.0 M silver nitrate and 30 mL of 2.0 M sodium chloride were added at 60 mL /
Were added simultaneously at a rate of minutes. This resulted in nucleation.

The mixture was then held for 10 seconds, after which a 0.5 M silver nitrate solution and a 0.5 M sodium chloride solution were added simultaneously at 5.3 mL / min for 60 minutes, maintaining the pCl at 2.35. The silver nitrate and sodium chloride solutions were then added using a linearly accelerated flow rate from 5.3 mL / min to 15.6 mL / min over 150 minutes.

The pCl was then adjusted to 1.55 with sodium chloride and 25 g of phthalated oxidized deionized gelatin was added and dissolved. The pH was then reduced to 3.85, stirring was stopped and the aggregates settled. At the end of the precipitation, the supernatant was discarded and distilled water was added back to the aggregate to bring it back to its original volume. The stirring was resumed, the pH was adjusted back to 5.36, and the pCl was 2.45.

With vigorous stirring, add 39 mL of 1.5 M potassium bromide solution.
It was added over 30 minutes to bring the pCl to 1.8.

The pH was adjusted to 5.8, and 25 g of phthalic oxidized deionized gelatin was added and dissolved. The pH was reduced to 3.85, stirring was stopped and the aggregates settled. Discard the supernatant, 27 g
Of low methionine gelatin and add emulsion weight with distilled water.
Increased to 800g. The pH was adjusted to 5.77 and the pCl was adjusted to 1.65 with 1.0 M sodium chloride solution.

The resulting emulsion had an average equivalent circular diameter of 1.67 μm and 0.135
It had an average grain thickness of μm. The halide composition was 93.964% silver chloride, 6.0% silver bromide and 0.0036% silver iodide. 75% of the particles had small edges with three or more epitaxy deposits.

Sensitization 0.15 moles of the emulsion was melted at 40 ° C. with stirring. To this was added 0.70 mmol / mol of green photosensitizing dye A, which was then held for 20 minutes. To this was added 1.0 mg / mol sodium thiosulfate pentahydrate and 1.3 mg / mol potassium tetrachloroaurate. Then raise the temperature to 60 over 12 minutes.
° C, held for 5 minutes, then cooled rapidly to 40 ° C. Then 70 mg / mol of APMT was added and the emulsion was cooled and solidified.

Emulsion C (Invention of the Invention) In this example, potassium bromide was added during the last step of precipitation to form an emulsion, whereby most of the grains were located on only one or two of the small edges 9 shows the precipitation and sensitization of a {100} silver chloride tabular emulsion with epitaxy deposits.

Precipitation 1536 mL of a solution containing 3.52% by weight of low methionine gelatin, 0.0056 M sodium chloride and 2.34 × 10 ⁻⁴ M potassium iodide was placed in a stirred reaction vessel at 40 ° C. and pH 5.74.
Manufactured by. While vigorously stirring this solution, 30 mL of 2.0 M silver nitrate and 30 mL of 2.0 M sodium chloride were added at 60 mL /
Were added simultaneously at a rate of minutes. This resulted in nucleation.

The mixture was then held for 10 seconds, after which a 0.5 M silver nitrate solution and a 0.5 M sodium chloride solution were added simultaneously at 8.0 mL / min for 40 minutes, keeping the pCl at 2.35. The silver nitrate solution and the sodium chloride solution were then added using a linearly accelerated flow rate from 8.0 mL / min to 16.1 mL / min over 130 minutes.

The pCl was then adjusted to 1.65 by adding sodium chloride solution at 20 mL / min for 8.0 minutes. Followed by 10
Hold for minutes. The pCl was then increased back to 2.15 by adding a silver nitrate solution at 5.0 mL / min for 27.7 minutes.
This was followed by the addition of a 1.5 M potassium bromide solution at 2.0 mL / min for 20 minutes to bring the pCl to 1.70.

Then 25 g of phthalic oxidized deionized gelatin was added and dissolved. The pH was reduced to 3.85, stirring was stopped and the aggregates settled. The supernatant was discarded and distilled water was added back to the original volume and added. The vigorous stirring was then resumed to adjust the pH back to 5.7. The pH was then adjusted back to 3.8 and stirring was stopped again to form aggregates. The supernatant was discarded again, 20 g of low methionine gelatin was added, and the emulsion weight was increased to 800 g with distilled water. The pH was adjusted to 5.77 and the pCl was adjusted to 1.65 with 1.0 M sodium chloride solution.

The resulting emulsion had an average equivalent circular diameter of 1.65 μm and 0.14 μm.
m. The halide composition was 93.964% silver chloride, 6.0% silver bromide and 0.0036% silver iodide. Examination of the emulsion by scanning electron microscopy showed that 97% of the grains had visible epitaxy deposits at two or less of the four available host tabular grain corners.

Sensitization The sensitization was the same as that used in Example 1, except that the levels of sodium thiosulfate pentahydrate and potassium tetrachloroaurate were increased by 50%.

Emulsion D (control) This emulsion consists of silver chloride cubic grains.
Precipitated in the same manner as the cubic grains in No. 10, and have the same grain volume as the three tabular emulsions of this example. This emulsion was sensitized as described below. Melt an amount at 40 ° C., add 500 mg / mol potassium bromide,
Subsequently, 0.2 mg / mol of sensitizing dye A was added and kept for 20 minutes. To this was added 0.25 mg / mol sodium thiosulfate pentahydrate and 0.50 mg / mol sodium aurous sodium dithiosulfate dihydrate, followed by raising the temperature to 65 ° C and holding for 12 minutes. The emulsion was then cooled rapidly.

Photographic Performance Each of the sensitized emulsions was coated with 1.1 g / m ² cyan dye-forming coupler C and 2.7 g / m ² on an antihalation support.
And 0.85 g / m ² of silver with gelatin. 1.6g of this
/ m ² of gelatin and cured with 1.75% bis (vinylsulfonylmethyl) ether of total coated gelatin weight. Using a coating film as a light source, a mercury vapor lamp
The intrinsic sensitivity was evaluated by exposing for 0.02 seconds in a step wedge sensitometer with a 5 nm line. Sensitivity to green light was filtered to simulate a daylight V light source, and filtered by Kodak Wratten ^™ 2B filter.
It was measured by exposing the coating for 0.02 seconds using a step wedge sensitometer with a 3000 K tungsten lamp filtered to transmit only light having a wavelength greater than 0 nm. Then, Kodak Flexi color ^TM
The coating was developed using the C-41 color negative development method. Dye concentration was measured using Status M red filtration.

 The photographic results are summarized in Table III.

In Table III, all of the {100} tabular grain emulsion examples were similarly sensitized to white light exposure, although Emulsions A and C showed less intrinsic sensitivity to 365 mercury exposure. It has been shown to be at least twice as sensitive as cubic grain emulsions.

Example 15 (Comparative) The purpose of this example was to ripen the process for producing tabular grain emulsions satisfying the requirements of the present invention--particularly as cited above.
To demonstrate the inability of the method described at the 1963 Turin Symposium.

75 mL of distilled water at 40 ° C., 6.75 g of deionized bone gelatin and
In a reaction vessel containing 2.25 mL of 1.0 M sodium chloride solution, with effective stirring, 15 mL of 1.0 M silver nitrate solution and 15 mL of 1.0 M
Sodium chloride solutions were added simultaneously at 15 mL / min each. The mixture was stirred at 40 ° C. for 4 minutes, then the temperature was increased to 10
The temperature was raised to 77 ° C. over a minute and 7.2 mL of a 1.0 M sodium chloride solution was added. The mixture was stirred at 77 ° C for 180 minutes, then cooled to 40 ° C.

The obtained particle mixture was examined by an optical microscope and an electron microscope. The emulsion contained a population of small cubes of about 0.2 μm edge length, large nontabular grains and tabular grains having square or rectangular major faces. In terms of number of particles, small particles were predominantly dominant.
Tabular grains accounted for less than 25% of the total grain projected area of the emulsion.

The average thickness of the tabular grain population was determined from edge-on views obtained using an electron microscope. All 26 tabular grains were measured and were found to have an average thickness of 0.38 μm. Of the 26 tabular grains measured for thickness, only one had a thickness less than 0.3 μm, and the thickness of one tabular grain was less than 0.3 μm.
It was 25 μm.

Example 16 This example has as its purpose to demonstrate the successful preparation of an emulsion satisfying the requirements of the invention using commercially available deionized gelatin.

In a reaction vessel equipped with a stirrer, add distilled water 28 g containing 20 g of deionized gelatin (purchased from Rousellot ^™ ).
65 g were added. Initial calcium ion level is 8 × 1
It was 0 ^-6 molar. Additional calcium ions as calcium chloride hydrate were added to the reaction vessel to compensate for calcium ion removal during gelatin deionization, thereby raising the calcium ion concentration to 2.36 mmol. 0.96 g sodium chloride and 45 g 0.012
By adding a molar potassium iodide solution,
Adjustment of the dispersion medium in the reaction vessel was completed. pH at 55 ° C
Adjusted to 6.5 and maintained at this value through precipitation by adding sodium hydroxide or nitric acid solution.

A 4.0 M silver nitrate solution and a 4.0 M sodium chloride solution were added at a rate that consumed 5% of the total silver for 30 seconds. Then the emulsion
Hold at 62 ° C. for 10 minutes, followed by the addition of 5000 g of a solution containing 1.6% deionized gelatin. Following this, pAg
Silver nitrate and sodium chloride were added simultaneously at a linearly increasing flow rate by a factor of 2.58 over a period of 70 minutes while maintaining a pH of 6.37. The total amount of precipitated silver iodochloride was 4.745 mol.

More than 80% of the total grain projected area was occupied by tabular grains. The tabular grains have an average EC of 1.65 μm
D, showing an average thickness of 0.165 μm and an average aspect ratio of 10.

When the above process was repeated using calcium acetate replaced by calcium chloride hydrate, more than 85% of the total grain projected area was occupied by tabular grains. The tabular grains exhibited an average ECD of 1.5 μm, an average thickness of 0.16 μm and an average aspect ratio of 9.4. When calcium ions in the dispersion medium were replaced with magnesium, aluminum or iron ions, emulsions satisfying the requirements of the present invention were obtained.

Example 17 This example is intended to demonstrate the exfoliation of high chloride {100} tabular grains by the introduction of bromide and / or iodide ions during the growth phase of the precipitate.

Emulsion 17A. Silver iodochloride {100} tabular grain emulsion 6000 mL of a solution containing 3.52% by weight of low methionine gelatin and 0.0056M sodium chloride was prepared at 40 ° C in a stirred reaction vessel. While vigorously stirring this solution,
90 mL of a 0.01 M potassium iodide solution was added, followed by 90 mL of 2.0 M silver nitrate and 90 mL of a 1.99 M sodium chloride and 0.01 M potassium iodide solution simultaneously at a rate of 180 mL / min each. The mixture was then held at a temperature that remained at 40 ° C. for 10 minutes. Following this hold, while maintaining the pCl at 2.25, add 12 mL of 1.0 M silver nitrate solution and 1.0 M sodium chloride solution.
/ Min at the same time for 40 minutes, followed by 12mL over 233.2 minutes
/ Min to 33.7 mL / min with linear acceleration. The pCl in the reaction vessel was then adjusted to 1.65 with sodium chloride, then the emulsion was washed to a pCl of 2.0 by ultrafiltration and concentrated. The pCl was adjusted to 1.65 with sodium chloride and the pH was adjusted to 5.7.

The resulting emulsion was a silver iodochloride {100} tabular grain emulsion containing 0.015 mol% of iodide. These emulsion grains
An average ECD of 1.51 μm and an average grain thickness of 0.21 μm were shown.

Emulsion 17B. This example shows 1 mol% between 89% at the end of precipitation.
It is shown that bromide ions in the halide salt solution at the level significantly reduce the average grain thickness of the emulsion.

This emulsion was prepared as emulsion 1 except that the halide salt solution used during the accelerated flow period of 233.2 minutes was a 0.99 M sodium chloride solution and a 0.01 M sodium bromide solution.
Manufactured the same as 7A.

The resulting high chloride {100} tabular grain emulsion contained 0.015 mol% iodide, 0.89 mol% bromide and 99.095 mol% silver chloride. The average ECD was 1.69 μm and the average thickness was 0.17 μm.

Emulsion 17C. This example shows 10 mol% between 89% at the end of precipitation
It is shown that bromide ions in the salt solution at the level significantly reduce the average grain thickness of the emulsion.

The emulsion was emulsion 1 except that the halide salt solution used during the accelerated flow period of 233.2 minutes was a 0.99 M sodium chloride solution and a 0.10 M sodium bromide solution.
Manufactured the same as 7A.

The resulting high chloride {100} tabular grain emulsion contained 0.015 mole% iodide, 8.9% bromide and 91.085 mole% silver chloride. The average ECD was 1.69 μm and the average thickness was 0.17 μm.

Emulsion 17D. Only silver chloride precipitated during the growth phase, 99.9
Silver iodochloride {100} tabular grain emulsion having a bulk composition of 7% silver chloride and 0.03% silver iodide 3.52% by weight low methionine gelatin, 0.0056M sodium chloride and 0.3mL polyethylene glycol defoamer 1.5 L of the containing solution was prepared at 40 ° C. in a stirred reaction vessel. While stirring the solution vigorously, 45 mL of a 0.01 M potassium iodide solution was added, followed by 50.25 mL of a 1.25 M silver nitrate solution.
0 mL and 50.0 mL of a 1.25 M sodium chloride solution were added to 10 mL each.
Added simultaneously at a rate of 0 mL / min. The mixture was then held at a temperature that remained at 40 ° C. for 10 seconds. Following this hold,
0.625M containing 0.08mg mercury chloride per mole of silver nitrate
Silver nitrate solution and 0.625 M sodium chloride solution at 10 mL / min.
Add simultaneously for 0 min, then add 10 mL / min to 1 over 125 min
By linearly accelerating to 5 mL / min, then 15 min for 30 min
Added at a constant flow rate of mL / min. During this time, pCl was maintained at 2.35. The pCl was then adjusted to 1.65 with sodium chloride solution. 50 g of phthalated gelatin were added and the emulsion was washed and concentrated using the method of Yutzy et al., US Pat. No. 2,614,928. The pCl after washing was 2.0. Add 34 g of low methionine gelatin, adjust pCl to 1.65 with sodium chloride,
Then the pH was adjusted to 5.7.

The resulting high chloride tabular grain emulsion had an ECD of 1.86 .mu.m and an average grain thickness of 0.11 .mu.m.

Emulsion 17E. This emulsion shows that the addition of low levels of iodide ion during the growth phase of the precipitation results in a lower average tabular grain thickness.

This emulsion was prepared by combining the salt solution used during the accelerated growth phase and the final constant growth phase with 0.621M sodium chloride and 0.001M.
Emulsion 17D, except that it had a composition of 4M potassium iodide
Precipitated as above.

The resulting high chloride {100} tabular grain emulsion was 1.8 μm
And an average grain thickness of 0.09 μm.

Example 18 This example illustrates the advantage of rapidly adding bromide ions during {100} average particle formation.

Emulsion precipitation: Emulsion 18A Silver iodobromide having a bulk halide composition of 96.964 mole% chloride, 0.036 mole% iodide and 3 mole% bromide, slowly added with bromide at 1.6 pCl over 30 minutes.
0 ° Tabular Emulsion 1.5 L of a solution containing 3.52 wt% low methionine gelatin, 0.0056 M sodium chloride and 0.3 mL polyethylene glycol antifoam were prepared at 40 ° C. in a stirred reaction vessel. While vigorously stirring this solution, 36 mL of a 0.01 M potassium iodide solution was added, followed by 50 m of a 1.25 M silver nitrate solution.
L and 1.25 M sodium chloride solution 50 mL, 100 mL / each
Were added simultaneously at a rate of minutes. The mixture was then held at a temperature that remained at 40 ° C. for 10 seconds. Following this hold, pCl
0.5M silver nitrate solution and 0.5M sodium chloride solution containing 0.08 mg mercuric chloride per mole of silver nitrate were added simultaneously at 10 mL / min for 30 minutes, while maintaining at 2.35, followed by 10 mL / min to 15 mL over 125 min. PCl was adjusted to 1.60 by linearly accelerating to 1 / min, then feeding 1.25 M sodium chloride solution at 20 mL / min for 8 min, followed by 10
Hold for minutes. Then a 0.5 M potassium bromide solution was added at 3.0 mL / min over 20 minutes. 50 g of phthalated gelatin were added and the emulsion was washed and concentrated using the method of Yutzy et al., US Pat. No. 2,614,929. The pCl after washing was 2.0. 21 g of low methionine gelatin was added, the pCl was adjusted to 1.65 with sodium chloride, and the pH was adjusted to 5.7. The resulting emulsion was a {100} tabular grain emulsion having an average ECD of 1.6 μm and an average grain thickness of 0.125 μm.

Emulsion 18B Silver iodobromide {100} tabular emulsion with a bulk halide composition of 96.964 mole% chloride, 0.036 mole% iodide and 3 mole% bromide, with rapid addition of bromide at a pCl of 1.7. At the end of the sloping growth, 1.5 M sodium chloride solution was added at 20 mL / min for 15 minutes, followed by 1.0 M
The same precipitation as in Emulsion 18A was performed, except that silver nitrate was added at 5.0 mL / min for 30 minutes. This was followed by the addition of 23 mL of a 1.5 M potassium bromide solution over about 1 second. The emulsion was then held for 10 minutes. The emulsion was treated with the same pCl as in the precipitation of emulsion 18A.
Then, the mixture was washed with a pH adjustment and concentrated. ECD of emulsion grains is 1.6μm
And the average grain thickness was 0.14 μm.

Emulsion 18C Silver iodobromide {100} tabular emulsion having a bulk halide composition of 97.964 mole% chloride, 0.036 mole% iodide and 2 mole% bromide, with slow addition of bromide at 1.6 pCl. Precipitate was the same as Emulsion 18A, except that a 0.625 M silver nitrate solution and a 0.625 M sodium chloride solution were used during a constant flow growth of 125 min and a slant flow growth of 125 min. 1.25M at end of ramp flow growth
Sodium chloride solution was added at 20 mL / min for 7.5 minutes, followed by
Hold for 10 minutes. This was followed by the addition of 60 mL of a 0.5 M potassium bromide solution at 3 mL / min over 20 minutes. Emulsion, emulsion
Washed and concentrated with the same pCl and pH controls as performed in the precipitation of 18A. The ECD of the emulsion grains was 1.5 μm and the average grain thickness was 0.12 μm.

Emulsion 18D Silver iodobromide {100} tabular emulsion with a bulk halide composition of 97.964 mole% chloride, 0.036 mole% iodide and 2 mole% bromide, with rapid addition of bromide at 2.3 pCl. Precipitate was the same as Emulsion 18A, except that a 0.625 M silver nitrate solution and a 0.625 M sodium chloride solution were used during 30 minutes of constant flow growth and 125 minutes of tilted flow growth. 1.25M at end of ramp flow growth
Sodium chloride solution was added at 20 mL / min for 7.5 minutes, followed by
Hold for 10 minutes. This is followed by a 1.25 M silver nitrate solution in 5.0
Added at mL / min for 30 minutes. This was followed by the addition of 60 mL of a 0.5 M potassium bromide solution over about 1 second. The emulsion was then held for 20 minutes. The emulsion was washed and concentrated with the same pCl and pH controls as performed in Emulsion 18A. ECD of emulsion grains
Was 1.8 μm and the average particle thickness was 0.14 μm.

Emulsion 18E Silver iodobromide {100} tabular emulsion having a bulk halide composition of 97.964 mol% chloride, 0.036 mol% iodide and 2 mol% bromide, with rapid addition of bromide at 1.6 pCl. Precipitate the same as Emulsion 18A, except that the addition of 150 mL of 1.25 M silver nitrate to adjust the pCl back to 2.3 before adding potassium bromide was omitted and the potassium bromide solution was added at 1.6 pCl. Was. The emulsion was washed and concentrated with the same pCl and pH controls as performed in Emulsion 18A. The ECD of the emulsion grains was 1.6 μm and the average grain thickness was 0.13 μm.

Sensitization of Emulsions 18A and 18B to Make Examples 18/1 to 18/4 The sensitization method is as follows. An amount of the emulsion suitable for experimental coating was melted at 40 ° C. The red spectral sensitizing dye was then added at a level estimated from specific surface area measurements. Hold for 15 minutes following addition of each dye. The red sensitizing dye was used as a set of two dyes. Set R-1 was prepared from dyes SS-23 and SS-25, which are red spectral sensitizing dyes, and a part of SS-25.
Per mole of SS-23. Then sodium thiosulfate pentahydrate was added at a level of 1.0 mg / mol Ag, followed by potassium tetrachloroaurate at 0.7 mg / mol Ag.
Added at the level of molar Ag. The temperature of the well-stirred mixture is then raised to 60 ° C. over 12 minutes and
It was kept at ° C. The emulsion was then cooled as quickly as possible to 40 ° C., then 70 mg / mol of APMT was added and the emulsion was chill set.

The photogrammetry each aspect, on antihalation support was coated with silver 0.85 g / m ² with 1.08 g / m ² of cyan dye-forming coupler C-1 and 2.7 g / m ² of gelatin. This layer was overcoated with 1.6 g / m ² gelatin and the entire coating was cured with bis (vinylsulfonylmethyl) ether at 1.75% by weight of the total coated gelatin. The coating is passed through a daylight V and Kodak Wratten ^™ 2B filter with a 3000K tungsten light source.
Exposure was through a step wedge for 0.02 seconds. An additional set of coatings is also available with a 365nm line emission from a mercury vapor lamp to 0.0
A 2 second exposure was given. The coating film was processed by a Flexicolor ^™ C-41 color negative developing method.

As shown in Table IV, Emulsion 18A provided thinner tabular grains, had a greater specific surface area, and became more sensitizing dye adsorbed, but had the same projected area and 365 Hg Emulsion 18B was significantly more sensitive despite its inherent sensitivity, as measured by line exposure, being about the same. This indicates that emulsion 18B is more efficient, so this is a function of the faster bromide addition described above.

Sensitization of Emulsions 18C-18E to Make Examples 18 / 5-18 / 16 The sensitization method is described in Examples 18 / 11-18 / 16 from the red spectral sensitizing dyes SS-23 and SS-25. Examples 18/1 to 18-18 except that a different red sensitizing dye combination R-2 was used, consisting of a molar ratio of 2 parts dye SS-23 to 1 part dye SS-25.
Same as used for 18/4.

Photographic measurements Coatings were prepared, exposed and developed as described for 18/1 to 18/4 above.

Table V and Examples 18/5 to 18/10 show that Emulsions 18D and 18E with the rapid addition of bromide, compared to Emulsion 18C, both had improved spectral (Kodak Wratten ^™ 2B filter) sensitivity and improved intrinsic properties. The sensitivity (365Hg ray exposure) is shown. The fact that the spectral sensitivity increase is greater than the intrinsic sensitivity increase is due to the bromide band formed by the rapid addition.
The interaction with the spectral sensitizing dye was improved, indicating that the transfer of photoelectrons from the sensitized dye so excited to silver halide grains was more effective.

Examples 18 / 11-18 / 16 demonstrate that this favorable interaction between an emulsion with a high bromide band formed by rapid bromide addition and a spectral sensitizing dye is used for the precipitation of the bromide band. This shows that it depends on both the sensitizing dye and the pCl used. Emulsion 18D, the bromide band of which was precipitated with 2.35 pCl, is again Emulsion 18C (slow bromide addition)
Showed very high spectral and intrinsic sensitivity to
Emulsion 18E to which bromide was rapidly added with pCl
Note that it showed a sensitivity in the region of spectral sensitization intermediate between that of (slow bromide addition) and that of the preferred example, Emulsion 18D.

By way of example, high chloride {100} tabular grain emulsions with bromide bands generally perform better when the bromide source is added rapidly. The performance of these emulsions is that rapid bromide addition can be achieved with relatively low excess chloride ions in solution with relatively low pCl
When performed by value, in some cases it will increase further.

Example 19 This example shows, for that purpose, the effectiveness of various ripening agents in increasing the percentage of total grain projected area occupied by {100} tabular grains.

Emulsion 19A: Control emulsion Solution: Solution A: 4M silver nitrate solution Solution B: 4M sodium chloride solution Solution C: 0.012M potassium iodide solution Solution D: distilled water containing 2.1 g of 6.5L sodium chloride E: 2.865L Of distilled water containing 0.96 g of sodium chloride, 25 g of gelatin and 90 mL of solution C: Solution E was placed in a reaction vessel equipped with a stirrer. The contents of the vessel were maintained at pH 6.5 and 55 ° C. While stirring the solution vigorously, the solution A and the solution B were added at 125 mL / min for 30
For 2 seconds.

Solution D was then added to the mixture. At the same time, the mixture temperature was raised to 62 ° C., the pCl was adjusted to 1.91, and the pH was maintained at 6.5 throughout the precipitation step. The mixture was then allowed to stand for 5 minutes. Following retention, then solution A
And B were added simultaneously at a linearly accelerated rate from 10 mL / min to 24 mL / min within 56 minutes while maintaining pCl at 2.14.

The resulting emulsion had 50% of its total grain projected area occupied by {100} tabular grains having an average ECD of about 1.4 μm and an average aspect ratio of 8. This emulsion contained a large amount of fine grains.

Emulsion 19B: Methionine as a growth accelerator Solution AA: 4M silver nitrate containing 2325 ppm of methionine Precipitated in the same manner as 19A. The resulting emulsion was essentially free of fine grains in which more than 65% of total grain projected area was occupied by {100} tabular grains having an average thickness of 0.16 μm and an average ECD of 1.5 μm.

Emulsion 19C: 1,10-dithia-4,7,13,16 as growth accelerator
This emulsion is identical to emulsion 19B except that solution AA contained 1162 ppm of 1,10-dithia-4,7,13,16-tetraoxacyclodecane instead of methionine. It was the same. The resulting emulsion was essentially free of fine grains where more than 65% of the total grain projected area was occupied by {100} tabular grains having an average thickness of 0.14 μm and an average ECD of 1.2 μm.

Emulsion 19D: 1,8-dihydroxy-3,6- as growth accelerator
Dithiaoctane This emulsion was the same as Emulsion 19B, except that Solution AA contained 23 ppm of 1,8-dihydroxy-3,6-dithiaoctane instead of methionine. The resulting emulsion contains 0.14μ more than 65% of the total grain projected area.
There were essentially no microparticles occupied by {100} tabular grains having an average thickness of m and an average ECD of 1.2 μm.

Emulsion 19E: 2,5-Dithiasveric acid as growth accelerator This emulsion was the same as Emulsion 19B, except that solution AA contained 58 ppm of 2,5-dithiasveric acid instead of methionine. Was. The resulting emulsion has an average thickness of 0.13 μm and more than 65% of the total grain projected area and 1.
There was essentially no fine particles occupied by {100} tabular grains having an average ECD of 2 μm.

Emulsion 19F: Glycine as Growth Accelerator This emulsion was emulsion 19B except that solution AA contained 5813 ppm glycine instead of methionine.
Was the same as The resulting emulsion has a total grain projected area of
More than 70% has an average thickness of 0.14 μm and an average E of 1.1 μm
There were essentially no fine particles occupied by {100} tabular grains with CD.

Emulsion 19G: Sodium sulfite as growth accelerator.This emulsion contained 174 ppm sodium sulfite instead of solution AA containing methionine.
Same as emulsion 19B. The resulting emulsion has an average thickness of 0.14 μm and 1.2 μm more than 65% of the total grain projected area.
There were essentially no microparticles occupied by {100} tabular grains having an average ECD of m.

Emulsion 19H: Thiocyanate as Growth Accelerator This emulsion was the same as Emulsion 19B except that Solution AA contained 79 ppm sodium thiocyanate instead of methionine. The resulting emulsion has an average thickness of more than 65% of total grain projected area of 0.15 μm and
There were essentially no microparticles occupied by {100} tabular grains having an average ECD of 1.1 μm.

Emulsion 19I: imidazole as growth accelerator This emulsion was prepared in the same manner as solution AA, except that solution AA contained 581 ppm imidazole instead of methionine.
Same as 19B. The resulting emulsion was essentially free of fine grains in which more than 60% of the total grain projected area was occupied by {100} tabular grains having an average thickness of 0.14 μm and an average ECD of 1.4 μm.

Examples 20-23 Iridium dopant at a concentration of 1.times.10.sup.- ⁹ to 1.times.10.sup.- ⁶ mole per silver mole, preferably 1.times.10.sup.- ⁸ to 1.times.10.sup.- ⁷ mole, was reciprocally reacted with the emulsion of the present invention. Intended for the purpose of reducing law failure. The photographic exposure is the product given by the formula: E = I × ti, where E is the exposure, I is the exposure intensity, and ti is the exposure time. Reciprocity failure is a term applied to the fact that when exposures are composed of different exposure intensities and exposure times, they do not result in equal exposures to produce the same photographic response. Iridium dopants are specifically intended to reduce low light reciprocity failure (LIRF)-i.e., Departure from reciprocity within an exposure time in the range of 10 ^-2 to 10 seconds.

Example 20 Emulsion 20A. Silver chloride {100} tabular grain emulsion containing potassium hexachloroiridate added after 80% of precipitation to give a bulk concentration of 0.05 mg / emulsion mole 3.52% by weight low methionine gelatin, 0.0056M 4900 mL of a solution containing sodium chloride and 1.0 mL of a polyethylene glycol antifoam were prepared at 40 ° C. in a stirred reaction vessel. While vigorously stirring this solution, 149 mL of a 0.01 M potassium iodide solution was added, followed by a 1.25 M silver nitrate solution.
95 mL of 95 mL and 1.25 M sodium chloride solution were added for 180
Added simultaneously at a rate of mL / min. The mixture was then held at a temperature that remained at 40 ° C. for 10 seconds. Following this hold,
By simultaneously adding 0.5 M silver nitrate solution and 0.5 M sodium chloride solution at 25 mL / min for 40 min while maintaining pCl at 2.35, followed by linear acceleration from 25 mL / min to 40.3 mL / min over 107 min. Was added. At this point, 30 mL of a 4 solution containing 5.12 mg potassium hexachloroiridate per liter was added over 1.2 minutes while continuing to increase the 0.5 M silver and salt solutions from 40.3 mL / min to 40.5 mL / min. did. Following the addition of the iridium salt, the addition of 0.5M silver nitrate solution and 0.5M sodium chloride solution was continued for 33.0 minutes at a linearly ramped flow rate from 40.5 mL / min to 45.0 mL / min. The pCl was then adjusted to 1.65 with sodium chloride, then the emulsion was washed to a pCL of 2.0 using ultrafiltration and concentrated. 16 g of low methionine gelatin was added, then the pCl was adjusted to 1.65 with sodium chloride and the pH was adjusted to 5.7.
The resulting emulsion was a tabular grain silver chloride emulsion containing 0.048 mol% iodide, having an average ECD of 1.64 .mu.m and 0.146 .mu.m.
m.

Emulsion 20B Silver chloride {100} tabular grain emulsion containing potassium hexachloroiridate added after 80% of precipitation to give a bulk concentration of 0.005 mg / emulsion mole This emulsion contains a solution containing an iridium salt per liter. Prepared the same as Emulsion 20A, except that it had a concentration of 0.512 mg. The resulting emulsion was a tabular grain silver chloride emulsion containing 0.048 mol% iodide, having an average ECD of 1.8 µm and an average grain thickness of 0.148 µm.

Emulsion 20C Silver chloride {100} tabular grain emulsion without iridium dopant This emulsion was prepared the same as Emulsion A except that no iridium salt solution was added. The resulting emulsion is a tabular grain silver chloride emulsion containing 0.048 mol% iodide,
It had an average equivalent circular grain diameter of 1.7 μm and an average grain thickness of 0.145 μm.

Sensitization Type I embodiments 1-26 This type of sensitization used sodium thiosulfate pentahydrate and potassium tetrachloroaurate as chemical sensitizers. Various sensitization modes were prepared in which the level of potassium bromide, the type of sensitizer, and the holding time at 60 ° C. were changed.

The sensitization method was as follows. An amount of the emulsion suitable for experimental coating was melted at 40 ° C. Potassium bromide was added, followed by a total of 0.7 mmol of green or red sensitizing dye. The green spectral sensitizing dye consisted of the dye SS-21. The red sensitizing dye was used as a set of two dyes. Set R-1 is a dye SS-23 which is a red spectral sensitizing dye.
And from dye SS-24, 8 parts of SS-23 per part of SS-24
The ratio was composed of: Set R-2 consisted of 2 parts SS-23 per 1 part SS-25 from dyes SS-23 and SS-25. Hold for 20 minutes following dye addition.
Then 1 mg / mol sodium thiosulfate pentahydrate and 0.1 mg / mol.
7 mg / mol potassium tetrachloroaurate was added. The temperature of the well-stirred mixture was then raised to 60 ° C. over 12 minutes and held at 60 ° C. for a specified time. The emulsion was then cooled as quickly as possible to 40 ° C., then 70 mg / mol of APMT was added and the emulsion was chill set.

Type II Aspect Nos. 27-30 This type of sensitization used a colloidal gold (II) sulfide suspension as a chemical sensitizer added after the addition of the sensitizing dye and potassium bromide.

The general sensitization method was as follows. An amount of the emulsion suitable for experimental coating was melted at 40 ° C. Embodiments 27 and 28 used Emulsion C and Embodiments 29 and 30 used Emulsion A. 0.
7 mmol / mol Ag of green sensitizing dye SS-21 was added to each emulsion. Hold for 20 minutes following dye addition. Then 60
0 mg / mol potassium bromide was added to embodiments 24 and 26, followed by a 10 minute hold. Then, 2.5 mg / mol of gold (II) sulfide was added, followed by a 5 minute hold. The temperature of the well-stirred mixture was then raised to 60 ° C. over 12 minutes and 60 minutes for 60 minutes.
It was kept at ° C. The emulsion was then cooled to 40 ° C. as quickly as possible, then 90 mg / mol of APMT was added and the emulsion was chill set.

Type III embodiments 31-34 This type of sensitization used a colloidal gold (II) sulfide suspension as a chemical sensitizer added at 40 ° C prior to the addition of the sensitizing dye.

The general sensitization method was as follows. An amount of the emulsion suitable for experimental coating was melted at 40 ° C. Embodiments 31 and 32 used Emulsion C and Embodiments 33 and 34 used Emulsion A. 0.
25 mg / mol gold (II) sulfide was added, followed by a 5 minute hold. In embodiments 27 and 29, the temperature was ramped to 60 ° C over 12 minutes, held at 60 ° C for 30 minutes, and ramped back to 40 ° C over 12 minutes. Embodiments 28 and 30 are at 40 ° C. during this same time.
And kept constant. 0.7 mmol / mol Ag sensitizing dye SS
-21 is added to each emulsion, followed by a 20 minute hold, then AP
MT 90 mg / mol was added, followed by cooling to solidification.

The photos that each embodiment, on antihalation support was coated with silver 0.85 g / m ² with 1.08 g / m ² of cyan dye-forming coupler C and 2.7 g / m ² gelatin. The layers were overcoated with gelatin 1.6 g / m ^2, the entire coating of total coating gelatin
Cured with 1.75% by weight bis (vinylsulfonylmethyl) ether. The coating was exposed with a Xenon lamp filtered through a Kodak Wratten ^™ 2B filter. The lamp intensity was varied with an Inconel filter so that different exposure times received the same total exposure. The coating film was developed by Kodak Flexicolor ^™ C-41 developing method.

That the iridium-containing emulsion exhibits improved reciprocity both in the 10 ^-4 to 10 s range as well as in the 10 ^-2 to 10 s (low intensity) range as compared to the iridium-containing embodiment with the iridium-free embodiment. You can know. Further, by examining the effects of iridium over a wide range of sensitizations, it can be seen that iridium improves the strength of reciprocity properties as a function of the degree of finish.

Examples 21 and 22 These examples show the effectiveness of iridium as a dopant to reduce low light reciprocity failure (LIRF) when iridium is located very close to the gelatin surface. In these examples, LIRF is 1/10 second exposure and 10
It was measured by comparing with the second exposure. Three individual silver iodochloride {100} tabular grain emulsions were prepared for use in these examples. Table VIII lists the particle size and iodide content.

The dopants used in combination with Emulsions S-1, 2 and 3 to improve LIRF are shown in Table IX.

Table IX dopant Formula _{D-1 K 3 IrCl 6 D} -2 K 4 Ir 2 Cl 10 D-3 K 6 Ir 6 Cl 24 following examples, various during the sensitization of emulsions S-1 to S-3 The amounts and use of these dopants at various locations are described.

The sensitized emulsion was coated on a cellulose acetate film support. The application format is gelatin 500mg / ft ² (53.
8 mg / dm ² ) Tabular silver chloride emulsion dispersed in 200 mg / ft
Emulsion layer consisting of ² (21.5mg / dm ^2), gelatin 100 mg / ft
² (10.8 mg / dm ² ) and a hardener, bis (vinylsulfonylmethyl) ether, at a level of 0.5% by weight based on total gelatin.

The coated photographic elements were evaluated for reciprocal response by giving them a series of calibrated (total energy) exposures ranging from 1/10 to 10 seconds. The exposed film was developed for 6 minutes in Hydroquinone-Elon ^™ (p-N-methylaminophenol hemisulphate) developing agent.

Example 21 This example illustrates the utility of dopant D-2 added during spectral sensitization by means of a pCl cycle consisting of continuous addition of chloride, D-2 and silver ions. Emulsion or pCl spectrally sensitized without dopant or pCl cycle due to introduction of dopant during pCl cycle
Emulsions having improved LIRF properties are obtained when compared to any of the emulsions that used cycling but did not use the dopant (otherwise being the same emulsion).

Emulsion S-1 was partially treated with dye 550 mg / silver mole of a blue spectral sensitizing dye, SS-1, and then spectrally sensitized by thermal ripening. Thereafter, APMT was added in an amount of 90 mg per mole of silver. This represents the control emulsion.

The other part of S-1 is composed of 2 mol% of chloride ion and D-
Spectral sensitization was performed in the same manner except that D-2 was contained by performing a pCl cycle of adding 2 mol% and then adding 2 mol% of silver ions. Such pCl cycles were performed either before or after treatment of S-1 with the sensitizing dye. These samples constitute examples of the present invention.

A final example was prepared in which a pCl cycle without dopant was performed to show the effect of a 2 mol% cycle without dopant effect.

Table X summarizes the photographic results of various amounts of D-2 added in the pCl cycle method.

From Table X it is clear that the use of D-2 reduces the LIRF of the emulsion. The sensitivities listed in Tables X, XI, XIII and XXIII are 100 times the logarithm of the exposure required to give a density 0.15 above the minimum density.

Example 22 This example demonstrates emulsion S when added by the pCl cycle method.
D to reduce LIRF for S-2 and S-3
The utility of -1, D-2 and D-3 is shown.

The separated portions of S-2 and S-3 were spectrally and chemically sensitized by treating each portion with 550 mg / silver mole of the blue spectral sensitizing dye, dye SS-1, followed by thermal ripening did. Next, 2 mg / mol of colloidal gold sulfide reagent was added, followed by heat aging at 60 ° C. for 30 minutes. Then raise the temperature to 40
C. and adjusted to 90 mg / mol APMT. The portion obtained represents an undoped emulsion for comparison with a doped emulsion.

Producing another undoped example in a similar manner except that a 2 mol% pCl cycle consisting of chloride ions followed by silver ions was performed after the dye addition and ripening steps but before the chemical sensitization step. did.

The other portion was spectrally and chemically sensitized by applying pCl cycles with varying amounts of dopant added and then treated with APMT as described above.

L of the portion containing the dopants D-1, D-2 and D-3
Photographic results showing the IRF improvement are shown in Table XI. A certain amount of D-1
And the significant increase in sensitivity obtained with D-3.

Example 23 This example illustrates the effectiveness of iridium to reduce LIRF when included during precipitation with a silver bromide Lippmann emulsion.

Emulsion S-3 described in Example 23 was used as the host high chloride {100} tabular grain emulsion.

Lippman silver bromide emulsions (about 0.08 μm edge length) were prepared with or without incorporated dopants. table
The types of Lippmann emulsions and dopants used in XII and the amounts contained in each emulsion are described. By blending the doped and undoped Lippmann emulsions, different dopant concentrations can be added to the host AgCl
Made available for inclusion in {100} T grain emulsions.

Portions of the host emulsion S-3 were spectrally and chemically sensitized by treating each portion with 550 mg / mole mole of the blue spectral sensitizing dye, dye SS-1, followed by thermal ripening.
Then 2 mg / silver mole of colloidal gold sulfide reagent was added,
Subsequently, heat aging was performed at 60 ° C. for 30 minutes. Thereafter, the temperature was adjusted to 40 ° C. and 90 mg / mol of APMT was added. The portion obtained represents an undoped emulsion made for comparison.

Other comparative emulsions were prepared in a manner similar to that described above, except that 2 mole percent of the undoped Lippman silver bromide emulsion was added after colloidal gold sulfide addition and thermal ripening. The Lippmann emulsion was added and an additional heat ripening at 60 ° C. for 10 minutes was performed. The temperature was then reduced to 40 ° C. and 90 mg / silver mole of A
PMT was added. This comparative example was performed to show the effect of undoped Lippmann bromide on the S-3 host emulsion.

Other portions of the S-3 host emulsion were added except that a doped Lippman Silver Bromide Emulsion or a blend of doped and non-doped Lippman Silver Bromide Emulsion was added and aged at 60 ° C. for 10 minutes. And sensitized in the same manner as in the above comparative example. Table XIII shows the LIRF benefits when doped Lippman additions are made.

Coating, exposure and development were performed as described in Example 22.

As shown in Table XIII, processing a high chloride {100} tabular grain host emulsion with an iridium-doped Lippman silver bromide emulsion results in a significant decrease in LIRF.

Example 24 A selenium-releasing compound such as potassium selenocyanate is used to sensitize high chloride {100} tabular grain emulsions, both as a replacement for sulfur and as an enhancement to sulfur and gold sensitization. Can be used for Advantages include lower fog at similar sensitivity and higher sensitivity at equal fog levels.

Emulsion precipitation: iodochloride {100} tabular grain emulsion with a bulk halide concentration of 99.954% chloride and 0.048% iodide on a molar basis 3.52% by weight low methionine gelatin, 0.0056M sodium chloride and 1.0 mL 4900 mL of a solution containing the polyethylene glycol defoamer was prepared at 40 ° C. in a stirred reaction vessel. While vigorously stirring this solution, 149 mL of a 0.01 M potassium iodide solution was added, followed by a 1.25 M silver nitrate solution.
95 mL of 95 mL and 1.25 M sodium chloride solution were added for 180
Added simultaneously at a rate of mL / min. The mixture was then held at a temperature that remained at 40 ° C. for 10 seconds. Following this hold,
0.5 M silver nitrate solution and 0.5 M sodium chloride solution are added simultaneously at 25 mL / min for 40 min while maintaining pCl at 2.35, followed by linear acceleration from 25 mL / min to 45 mL / min over 140 min did. Then pCl with sodium chloride
Was adjusted to 1.65, then the emulsion was 2.
Washed to 0 pCl and concentrated. Low methionine gelatin 16g
Was added, then the pCl was adjusted to 1.65 with sodium chloride and the pH was adjusted to 5.7.

The resulting emulsion was a chloride {100} tabular grain emulsion containing 0.048 mol% of iodide and had an average grain size of 1.64 μm.
It had a CD and an average grain thickness of 0.146 μm.

Sensitization: A sample of the emulsion was melted at 40 ° C. Potassium bromide was added, followed by a total of 0.7 mmol per mole of emulsion, dye SS-21, a green spectral sensitizing dye. Hold for 20 minutes following dye addition. Then (only for certain samples) sodium thiosulfate pentahydrate was added, followed by 0.7 m
g / silver mole of potassium tetrachloroaurate was added. This was followed by (for some samples only) potassium selenocyanate. The temperature of the well-stirred mixture was then reduced to 12
The temperature was raised to 60 ° C. over a period of minutes and held at 60 ° C. for a specified time. The emulsion is then cooled as quickly as possible to 40 ° C.
70 mg / mol MT was added and the emulsion sample was cooled and solidified.

A sample of each emulsion was prepared by placing 1.08 g / m ² of cyan dye-forming coupler C on a support having an antihalation backing.
-1 and 2.7 g / m ² with gelatin was coated at silver 0.85 g / m ^2. This emulsion layer was overcoated with 1.6 g / m ² gelatin and the entire coating was hardened with bis (vinylsulfonylmethyl) ether at 1.75% by weight of total coated gelatin.

The photographic evaluation photographic element, through step wedge with a tungsten lamp was filtered light with Kodak Wratten ^TM 2B filter 1 /
Exposure was for 50 seconds. Kodak coating film FLEXICOLOR ^TM C-4
Developed by 1 color negative developing method.

Samples containing selenium included those that yielded the lowest minimum concentration and those that yielded the highest sensitivity.
Overall, it is clear that the use of selenium improves performance when both sensitivity and minimum density are taken into account.

Example 25 This example illustrates the effect of including K ₂ Ru (CN) ₆ as a dopant during precipitation.

Silver iodochloride (0.05 mol% iodide) according to the present invention {100}
The tabular grain emulsions were prepared K ₂ Ru (CN) ₆ of 10mppm with silver occupying a portion of the 85% to 95% of the operation of the total silver added was added. In the resulting emulsion, more than 50% of the total grain projected area was occupied by tabular grains having {100} major faces. The average grain ECD is 1.44 μm and the average grain thickness is 0.1
It was 47 μm. The emulsion is washed by ultrafiltration and its pH
And pCl were adjusted to 5.6 and 1.6, respectively. Hereinafter this emulsion is referred to as emulsion 25 / D.

A comparative emulsion, hereinafter referred to as Emulsion 25 / UD, was prepared with K ₂ Ru (C
N) Precipitation was performed in the same manner except that the ₆ dopant was removed. In the resulting emulsion, more than 50% of the total grain projected area was occupied by tabular grains having {100} major faces.
The average particle ECD is 1.61 μm and the average particle thickness is 0.150 μ
m. The emulsion is washed by ultrafiltration, its pH and
pCl was adjusted to 5.6 and 1.6, respectively.

Each emulsion was combined with a yellow dye-forming coupler stabilized with benzenesulfonic acid. Each emulsion was coated on a resin-coated paper support with 2.8 mg of silver / dm ² and 10.8 m of dye-forming coupler.
g / dm ² and gelatin 8.3 mg / dm ² .

Samples of the emulsion coatings were given equal exposures at 100, 1/2 and 1/100 seconds. HIRF was measured as the difference in photographic sensitivity between 1/100 second exposure and 1/2 second exposure, while LIRF was measured as the difference in photographic sensitivity between 100 second exposure and 1/2 second exposure. Latent image retention was measured as the sensitivity difference between the strips developed 30 seconds and 30 minutes after exposure. Thermal sensitivity was measured as the sensitivity difference between exposure at 40 ° C. and room temperature. The rapid access Kodak RA-4 ^™ method was used.

Although both emulsions have shown photographic utility, the basic advantages of Emulsion 25 / D over Emulsion 25 / UD are higher sensitivity with comparable latent image retention, improved foot sharpness and higher contrast As well as thermal sensitivity levels. Emulsion 25 / D also exhibits higher sensitivity at shorter exposure times and lower sensitivity at longer exposure times, both of which are advantageous in particular photographic applications.

Example 26 This example demonstrates the purpose of High Light Reciprocity Failure (HIRF)
To demonstrate the effectiveness of iron hexacyanide as a dopant in high chloride {100} tabular grain emulsions to lower

Emulsion 26/1 Eight solutions were prepared as follows.

Solution 1 (26/1) Gelatin (bone) 211 gm NaCl 1.96 gm DW 5800 mL Solution 2 (26/1) KI 0.15 gm DW 90 mL Solution 3 (26/1) NaCl 207 gm DW 7000 mL Solution 4 (26/1) NaCl 13.1 gm DW 108mL Solution 5 (26/1) AgNO ₃ solution 5.722 molar concentration 922gm DW 5425mL Solution 6 (26/1) AgNO ₃ solution 5.722 molar concentration 922gm DW 73.7mL Solution 7 (26/1) Gelatin (phthalic oxidation) 100gm DW 1000mL Solution 8 (26/1) Gelatin (bone) 80 gm DW 1000 mL Solution 1 (26/1) was placed at 40 ° C. in a reaction vessel equipped with a stirrer.
Put in. Solution 2 (26/1) was placed in a reaction vessel and the pH was adjusted to 5.7.
Was adjusted to While stirring the reaction vessel vigorously,
(26/1) and Solution 6 (26/1) were added at 180 mL / min for 30 seconds. The reaction vessel was held for 10 minutes. Following this hold, solution 3 (26/1) and solution 5 (26/1) were added simultaneously at 24 mL / min for 40 minutes, maintaining pCl at 1.91. Then increase the speed to 130
Accelerated to 48 mL / min over minutes. Then mix 40
After cooling to ° C., solution 7 (26/1) was added and stirred for 5 minutes.
The pH was then adjusted to 3.8 to precipitate the gelatin. At the same time, the temperature was reduced to 15 ° C. before decanting the liquid phase. The reduced volume was reconstituted with distilled water. Adjust pH to 4.5 and mix 4
It was kept at 0 ° C. for 20 minutes, after which the pH was adjusted to 3.8 and the precipitation and decantation steps were repeated. Solution 8 (26/1) was added and the pH and pCl were adjusted to 5.6 and 1.6, respectively.

Emulsion 26/2 The second emulsion (26/2) was prepared in the same way as the first emulsion (26/1), except that solution 3 (36 mg K ₄ Fe (CN) ₆ in 278 g of solution) A solution similar to 26/1) was added at 4 mL / min in the same manner as solutions 3 and 5 were accelerated. This addition continued for 70 minutes.

Emulsions 26/1 and 26/2 were treated with 0.5% NaBr, held for 5 minutes, and combined with a spectral sensitizing dye (3: 1 molar ratio of dye SS-21).
And adding a dye SS-26), and held 10 _{min, Na 2 S 2 O 3 ·} 5
Of H ₂ O was added 1.2 mg / mole and in KAuCl ₄ at 1.6 mg / mole,
And it finished by heating at 60 degreeC for 10 minutes. After the heating step, APMT was added at 90 mg / mol. The finished emulsion was coated at ^{50mg / ft 2 (5.38mg / dm} 2) 50mgAg / ft 2 with a mixture of magenta dye-forming coupler in (5.38mg / dm ^2). The coating was overcoated with gelatin and cured.
Samples of the coating film were equally exposed at 10 intervals ranging from 1 × 10 ^{−5 to} 0.1 second and developed for 2 minutes and 15 seconds by Kodak Flexicolor ^™ C-41 color negative developing method. The results are shown in Table XV
To summarize. Sensitivity is measured at a concentration 0.35 higher than fog.

Example 27 This example illustrates the use of a desensitizing dopant with a high chloride {100} tabular grain emulsion.

Emulsion 27/1 Seven solutions were prepared as follows.

Solution 1 (27/1) Gelatin (bone) 75 gm NaCl 2.88 gm DW 4300 mL Solution 2 (27/1) KI 0.44 gm DW 220 mL Solution 3 (27/1) NaCl 397.4 gm DW to a total volume of 1700 mL Solution 4 (27 / 1) NaCl 4.3gm DW 6500mL Solution 5 (27/1) AgNO ₃ 5.722M solution 2110gm DW 518mL Solution 6 (27/1) Gelatin (phthalic oxidation) 200gm DW 1500mL Solution 7 (27/1) Gelatin (bone) 130gm DW 1500 mL of solution 1 (26/1) was placed in a reaction vessel equipped with a stirrer. Solution 2 (27/1) was added to the reaction vessel, the pH was adjusted to 6.5, and the temperature was raised to 55 ° C. While stirring the reaction vessel vigorously, add solution 3 (27/1) and solution 5 (27/1) to 45 mL /
For 1 minute. Solution 4 (27/1) was then added to the mixture. The temperature was increased to 62 ° C., the pCl was adjusted to 1.91, and the pH was maintained at 6.5. The mixture was held for 5 minutes.
Following this hold, solution 3 (27/1) and solution 5 (27/1)
From 15 mL / min for 56 minutes each while maintaining pCl at 1.91.
Simultaneous additions were made at linearly accelerated rates ranging up to 37 mL / min. The mixture was then cooled to 40 ° C and solution 6 (27 /
1) was added and stirred for 5 minutes. The pH was then adjusted to 3.2,
Gelatin was precipitated. At the same time, the temperature was reduced to 15 ° C. before decanting the liquid phase. The reduced volume was reconstituted with distilled water.
The pH was adjusted to 4.5 and the mixture was kept at 40 ° C. for 20 minutes, after which the pH was adjusted to 3.2 and the precipitation and decantation steps were repeated.
Solution 7 (27/1) was added and the pH and pCl were adjusted to 5.6 and pCl, respectively.
Adjusted to 1.6.

Emulsion 27/2 The second emulsion (27/2) was prepared in the same manner as 27/1, but with K ₃ Os
(NO) a Cl ₅ were added in the form total concentration of 0.1mppm in 70-80% of the band of the salt and silver addition.

Emulsion 27/3 A third emulsion (27/3) was prepared in the same manner as 27/1, but with K ₃ Ru
(NO) a Cl ₅ were added in the form total concentration of 0.1mppm in 70-80% of the band of the salt and silver addition.

Emulsion 27 / 4M A fourth emulsion (27/4) was prepared in the same manner as 27/1, but with K ₃ RhCl
₆ was added at a format total concentration of 0.1 mppm in a 70-80% band of salt and silver addition.

Emulsions 27/1, 27/2 and 27/3 were treated with 1.5% NaBr, held for 5 minutes, and the spectral sensitizing dye SS-22 was added.
Held _{minutes, Na 2 S 2 O 3 ·} 5H 2 O and 1.6 mg / mol and in KAuCl ₄
Was added at 1.0 mg / mol and chemically and spectrally sensitized by heating at 60 ° C. for 10 minutes. After the heating step, APMT was added at 100 mg / mol. 5.4mg / dm of this emulsion
Coated at 5.4 mg Ag / dm ² with ^two magenta dye-forming couplers. The coating was overcoated with gelatin and cured. Daylight exposure through a Wratten ^TM W9 filter coating
Giving 0.02 seconds, Kodak coating film FLEXICOLOR ^TM C-41
Development was performed for 3 minutes and 15 seconds by the color negative development method. The results are summarized in Table XVI. Sensitivity was measured at a concentration 0.20 higher than fog.

Part of emulsion 27/1 that was not previously sensitized (hereinafter emulsion 27/1
M) and emulsion 27 / 4M were treated with 2% NaBr and held for 5 minutes to give a spectral sensitizing dye mixture (2: 1 molar ratio of dye SS-2).
3 and the dye SS-25) were added, and the mixture was kept for 10 minutes to give Na ₂ S ₂ O _3.
5H ₂ O at 1.6 mg / mol and KAuCl ₄ at 1.0 mg / mol,
It was chemically and spectrally sensitized by heating at 60 ° C. for 10 minutes. After the heating step, APMT was added at 100 mg / mol. The finished emulsion with a magenta dye-forming coupler of 5.4 mg / dm ² was applied with 5.4mgAg / dm ^2. The coating was overcoated with gelatin and cured. Ratten on the coating
^The coating was developed for 3 minutes and 15 seconds with a Kodak Flexicolor ^™ C-41 color negative development method for 0.02 seconds of daylight exposure through a TM9 filter. The results are summarized in Table XVI. Sensitivity was measured at a concentration 0.20 higher than fog.

Table XVI Emulsifiers Dopant level Sensitivity (logE) 27/1 undoped 2.54 27/2 0.1mppm 1.46 27/3 0.1mppm 0.62 27 / 1M undoped 2.36 27 / 4M 0.1mppm 0.76 Example 28 Demonstrates the use of shallow electron capture dopants with the {100} tabular grain emulsions.

Emulsion 28/1 Eight solutions were prepared as follows.

Solution 1 (28/1) Gelatin (bone) 211 gm NaCl 1.96 gm DW 5798 mL Solution 2 (28/1) KI 0.15 gm DW 90 mL Solution 3 (28/1) NaCl 206.7 gm DW 7000 mL Solution 4 (28/1) NaCl 13.1 gm KI 0.19 gm DW 108 mL solution 5 (28/1) AgNO ₃ 5.722 M solution 70 gm DW to a total volume of 112 mL Solution 6 (28/1) AgNO ₃ 5.722 M solution 922 gm DW 542.6 mL solution 7 (28/1) Gelatin (28/1) (Phthalic oxidation) 100 gm DW 1000 mL solution 8 (28/1) Gelatin (bone) 80 gm DW 1000 mL solution 1 (28/1) was placed in a reaction vessel equipped with a stirrer. Solution 2 (28/1) was added to the reaction vessel. The pH was adjusted to 5.7 and the temperature was raised to 40 ° C. While stirring the reaction vessel vigorously, the solution 4 (28/1) and the solution 5 (28/1)
Added at L / min for 0.5 minutes. The pCl was adjusted to 2.3. The mixture was held for 10 minutes. Following this hold, solution 3 (28/1)
And solution 6 (28/1) at 24 mL / min with pCl maintained at 2.3.
Added simultaneously for 0 min, then the flow was linearly accelerated from 24 mL / min to 48 mL / min over 130 min. Solution 7 (28/1) was added and stirred for 5 minutes. The pH was then adjusted to 3.8 to precipitate the gelatin. At the same time, the temperature was reduced to 15 ° C. before decanting the liquid phase. The reduced volume was reconstituted with distilled water. pH 4.5
And maintain the mixture at 40 ° C. for 5 minutes, after which the pH is adjusted to 3.
Adjusted to 8 and the precipitation and decantation steps were repeated. Solution 8 (2
8/1) and the pH and pCl were adjusted to 5.6 and 1.6, respectively.

Emulsion 28/2 The second emulsion (28/2) was prepared in the same way as 28/1, but with K ₄ Ru
(NO) ₆ was added at a format total concentration of 25 mppm in a band ranging from 70-80% of the halide and silver addition.

Emulsion 28/3 The third emulsion (28/3) was prepared in the same way as 28/1, but with K ₄ Ru
(NO) ₆ was added at a formal total concentration of 50 mppm in a band ranging from 70-80% of the halide and silver addition.

Emulsions 28/1, 28/2 and 28/3 were treated with 1% NaBr, held for 5 minutes, added with a spectral sensitizing dye (dye I-22), held for 10 minutes, Na ₂ S ₂ O ₃ 5H ₂ O at 0.8 mg / mol and KAuCl ₄
Finished by adding at 1.0 mg / mol and heating at 60 ° C. for 10 minutes. After the heating step, APMT was added at 120 mg / mol. The finished emulsion with a magenta dye-forming coupler of 5.4 mg / dm ² was applied with 5.4mgAg / dm ^2. The coating was overcoated with gelatin and cured. 1 sample of coating film
Exposure was performed equally at 10 time intervals in the range of × 10 ^-5 to 1/10 second, and development processing was performed for 2 minutes by the Kodak Flexicolor ^™ C-41 color negative development method. The results are summarized in Table XVII. Sensitivity is measured at a concentration 0.35 higher than fog.

Example 29 Under oxidizing conditions, where low pH shows a significant decrease in fog level without loss of sensitivity after spectral and chemical sensitization,
Precipitation and / or addition of mild silver oxidizer during precipitation. Mild silver oxidizers include inorganic salts such as mercury salts or potassium tetrahaloaurate and organic compounds that release silver oxidizing species such as elemental sulfur, such as 4.4'-phenyldisulfidediacetanilide.

Emulsion 29A (no oxidation) Silver bromochloride (3% bromide) {100} tabular grain emulsion with no oxidizing agent added or with no precipitation modification to reduce fog, 3.52% by weight low methionine gelatin, 0.0056M Of sodium chloride and 1.0 mL of a polyethylene glycol antifoam were prepared at 40 ° C. in a stirred reaction vessel. While stirring the solution vigorously, 135 mL of 0.01 M potassium iodide solution was added, followed by 15 mL of 1.25 M silver nitrate solution.
0 mL and 150 mL of a 1.25 M sodium chloride solution
Added simultaneously at a rate of mL / min. The mixture was then held at a temperature that remained at 40 ° C. for 10 seconds. Following this hold,
While maintaining the pCl at 2.35, a 0.625 M silver nitrate solution and 0.625 M
M sodium chloride solution was added simultaneously at 30 mL / min for 30 minutes,
This was followed by linear acceleration from 30 mL / min to 45 mL / min over 125 minutes. At this point, 480 mL of 1.25 M sodium chloride was added over 8 minutes, followed by a 10 minute hold. Next, a 1.25 M silver nitrate solution was added at 15 mL / min for 30 minutes, and then 180 mL of 0.5 M sodium bromide was added, and the emulsion was added for 2 minutes.
Hold for 0 minutes. The pCl was then adjusted to 1.65 with sodium chloride and the emulsion was then washed using ultrafiltration to a pH of 2.0.
Concentrated to Cl. Add 10 g of low methionine gelatin,
The emulsion was adjusted with sodium chloride to a pCl of 1.65 and a pH of 5.7. The resulting emulsion was a tabular grain silver chloride emulsion containing 3% silver bromide and 0.032 mole% iodide. This emulsion had an average grain ECD of 1.8 μm and an average grain thickness of 0.15 μm.

Emulsion 29B (with oxidation) This emulsion was prepared except that mercuric chloride was added to the silver nitrate solution at a concentration of 0.08 mg of mercuric chloride per mole of silver nitrate.
Emulsion 29A was prepared the same as Emulsion 29A.

Emulsion 29C (with oxidation) This emulsion contains potassium tetrachloroaurate and 69% of total silver.
% Except that it was added to the silver nitrate solution at a concentration of 0.2 mg / mole silver during a 125 minute gradient flow growth period in which% precipitated.
Emulsion 29A was prepared the same as Emulsion 29A.

Emulsion 29D (oxidized) This emulsion converts 4.4'-diphenyldisulfidediacetanilide into a silver nitrate solution at a concentration of 1.0 mg per mole of silver during a 125 minute gradient flow growth period in which 69% of the total silver was precipitated. Except for the addition, it was prepared in the same manner as Emulsion 29A.

Emulsion 29E (with oxidation) This emulsion was prepared identically to Emulsion 29A, except that the pH of the emulsion was adjusted from 5.7 to 4.5 with nitric acid after 17% of the total silver had precipitated. The pH was kept at 4.5 until the precipitation was complete,
The emulsion was washed and adjusted back to 5.7 after the final gelatin was added.

Sensitization and coating An amount of the emulsion suitable for coating was melted at 40 ° C. Potassium bromide was added, followed by the spectral sensitizing dye SS-21.
Was added. Hold for 20 minutes following dye addition. Next, sodium thiosulfate pentahydrate, a sulfur sensitizer, potassium tetrachloroaurate, and a gold sensitizer were added. The temperature of the well-stirred mixture was then raised to 60 ° C. over 12 minutes and held at 60 ° C. for the following time. The emulsion was then cooled as quickly as possible to 40 ° C., 70 mg / mol of APMT was added and the emulsion samples were cooled and solidified.

A sample of each emulsion was prepared by placing 1.08 g / m ² of cyan dye-forming coupler C on a support having an antihalation backing.
-1 and 2.7 g / m ² with gelatin was coated at silver 0.85 g / m ^2. This emulsion layer was overcoated with 1.6 g / m ² gelatin and the entire coating was hardened with bis (vinylsulfonylmethyl) ether at 1.75% by weight of total coated gelatin.

The photographic evaluation photographic element, through step wedge with a tungsten lamp was filtered light with Kodak Wratten ^TM 2B filter 1 /
Exposure was for 50 seconds. Kodak coating film FLEXICOLOR ^TM C-4
Developed by 1 color negative developing method.

From Table XVIII, it is clear that the presence of mild oxidizing agents or oxidizing conditions during emulsion precipitation reduces fog while preserving essentially the same photographic speed.

Example 30 This example demonstrates that the addition of a benzothiazolium salt during sensitization shows higher sensitivity and lower fog
0 indicates that a tabular grain emulsion is to be made.

 The emulsion was precipitated as described in Example 24.

A sample of the sensitized emulsion was melted at 40 ° C. Potassium bromide was added, followed by a total of 0.7 mmol per mole of emulsion, dye SS-21, a green spectral sensitizing dye. Hold for 20 minutes following dye addition. Sodium thiosulfate pentahydrate was then added at a level of 1.0 mg / silver mole followed by 0.7 mg / silver mole.
Silver moles of potassium tetrachloroaurate were added. This was followed by (in one example) 5 mg of 3- (2-methylsulfonylethyl) benzothiazolium tetrafluoroborate (hereinafter BTZTFB) per mole of silver. The temperature of the well-stirred mixture was then raised to 60 ° C. over the time specified in Table XIX below. The emulsion was then cooled as quickly as possible to 40 ° C., 70 mg / mol of APMT was added and the emulsion samples were cooled and solidified.

A sample of each emulsion was prepared by placing 1.08 g / m ² of cyan dye-forming coupler C on a support having an antihalation backing.
-1 and 2.7 g / m ² with gelatin was coated at silver 0.85 g / m ^2. This emulsion layer was overcoated with 1.6 g / m ² gelatin and the entire coating was hardened with bis (vinylsulfonylmethyl) ether at 1.75% by weight of total coated gelatin.

Photographic evaluation Photographic elements were evaluated using daylight V filters and Kodak Wratten.
Was exposed 1/50 sec through a step wedge with 3000 ° K tungsten lamp was filtered light with ^TM 9 filter. The coating film was developed by Kodak Flexicolor ^™ C-41 color negative developing method.

From Table XIX it is clear that the addition of a benzothiazolium salt during sensitization not only increases the sensitivity but also lowers the minimum density.

Example 31 This example demonstrates the effectiveness of various spectral sensitizing dyes in increasing the sensitivity of high chloride {100} tabular grain emulsions.

3 × 10 3 per mole of silver added with silver salt during precipitation
Silver iodochloride containing ^-7 mol of mercury (0.05 mol% iodide)
A {100} tabular grain emulsion was used. Tabular grains having {100} major faces accounted for more than 50% of the total grain projected area. Emulsion grain ECD is 1.37 μm, average grain thickness is 0.1
It was 48 μm. The emulsion is washed by ultrafiltration and its pH
Was adjusted to 5.6 and its pCl was adjusted to 1.6.

This emulsion was chemically and spectrally sensitized according to the following scheme.

1.61 g Ag / m ^{2 of} this sample was placed on an unprimed 7 mil (178 μm) polyacetate butyrate film support.
And 3.23 g gelatin / m ² . A surfactant was added as a coating aid and bis (vinylsulfonylmethyl) ether at 1.5% by weight was used as a curing agent.

Coating absorbance measurements were used to determine the wavelength of maximum light absorption for the dye. Exposure and development processing is 1/5 second5
Hydroquinone-Elon ^™ (p-N-methylaminophenol hemisulfate) developing agent (Kodak DK)
−50 ^™ ), stop bath, fixation (Kodak F-5)
^TM ) and washing. The sensitivity of the coating,
It was measured as the exposure required to produce a density 0.15 higher than the minimum density. The comparative coating film without the addition of the dye was given a sensitivity value of 100 for the purpose of comparison, and all the examples with the addition of the dye are shown relative to those without the addition of the dye. Table XXI data
To summarize.

Example 32 The following example illustrates the use of a blue spectral sensitizing dye combination to spectrally sensitize high chloride {100} tabular grain emulsions.

 The same emulsion as in Example 31 was used.

This emulsion was chemically and spectrally sensitized according to the following scheme.

Each spectrally sensitized emulsion sample was double melted with Dispersion A, Dispersion B and a common dye-forming coupler dispersion melt containing surfactant. The sample is lined with a carbon black (Remjet ^™ ) anti-paration backing,
Coated on 5 mil (125 μm) cellulose triacetate support subbed with 4.88 g / m ² gelatin. The emulsion and coupler were coated at a level of 968 mg / m ² silver, 484 mg / m ² dye forming coupler Y-1 and 484 mg / m ² dye forming coupler Y-2. A surfactant was added as a coating aid.
This emulsion layer was overcoated with 1.08 g / m ² gelatin,
Cured with 1.75% bis (vinylsulfonylmethyl) ether based on total gelatin.

Dispersion A contains 9% by weight of yellow dye-forming coupler Y-1, 6% by weight of deionized gelatin, 0.44% of sodium triisopropylnaphthalenesulfonate (anionic surfactant) and 1.1% of 2N propionic acid. Was included.

Dispersion B has the following composition: 9% by weight of yellow dye-forming coupler Y-2, 4.5% of dibutyl phthalate,
With 6.5% gelatin, 0.6% sodium triisopropylnaphthalenesulfonate (anionic surfactant),
The pH was adjusted to 5.1 with 2N propionic acid.

Samples from these coatings were given a 1/50 second step wedge exposure from a 5500 ° K light source through a Wratten ^™ 2B filter. The sample Kodak Flexi color ^TM C41
Development was performed using the color negative development method, but the composition of the bleaching solution was modified to include propylenediaminetetraacetic acid. The minimum density was measured and the photographic speed was determined as 100 times the log of the exposure required to give a density 0.15 above the minimum density. The data is summarized in Table XXIII.

The data in Table XXIII indicate that the combination of dyes is high chloride {100}
Not only is it useful for spectral sensitization of tabular grain emulsions, it also shows that this combination has a synergistic effect. The combination of dyes gives the emulsion a higher sensitivity than either dye alone.

Example 33 This example has as its purpose to demonstrate the effectiveness of the combination of spectral sensitizing dyes in high chloride {100} tabular grain emulsions.

Emulsion preparation 1.5 L of a solution containing 3.52% by weight of low methionine gelatin, 0.0056 M sodium chloride and 0.3 mL of polyethylene glycol antifoam were prepared at 40 ° C. in a stirred reaction vessel. While stirring the solution vigorously, 45 mL of a 0.01 M potassium iodide solution was added, followed by 50 mL of a 1.25 M silver nitrate solution and 50 mL of a 1.25 M sodium chloride solution at a rate of 100 mL / min each. The mixture was then held at a temperature that remained at 40 ° C. for 10 seconds. Following this hold, pCl
Mercuric chloride per mole of silver nitrate while maintaining 2.35
A 0.625 M silver nitrate solution containing 0.08 mg and a 0.625 M sodium chloride solution are added simultaneously at 10 mL / min for 30 min, followed by 125 mL
Addition was made by linear acceleration from 10 mL / min to 15 mL / min over a minute, followed by constant flow growth at 15 mL / min for 30 minutes. The pCl was then adjusted to 1.65 with sodium chloride. 50 g of phthalated gelatin was added and the emulsion was washed and concentrated using the method of Yutzy et al., US Pat. No. 2,614,928. The pCl after washing was 2.0. Low methionine gelatin
Add 21 g, adjust pCl to 1.65 with sodium chloride, pH
Was adjusted to 5.7.

The resulting emulsion was a silver iodochloride {100} tabular grain emulsion containing 0.036 mol% of iodide. This emulsion is 1.6μ
It had an average particle ECD of m and an average particle thickness of 0.125 μm.

Sensitization A series of samples of different emulsions was sensitized. In each sensitization, an amount of emulsion suitable for coating was melted at 40 ° C.
Potassium bromide is added, followed by a total of 0.
7 mmol of green spectral sensitizing dye was added. When the two green spectral sensitizing dyes were added, the ratio of the first dye to the second dye was as shown in Table XXIV. Following dye addition
Hold for 20 minutes. This was followed by the addition of 1.0 mg / mol sodium thiosulfate pentahydrate, followed by 0.7 mg / mol potassium tetrachlorogold silver. The temperature of the well-stirred mixture was then raised to 60 ° C. over 12 minutes and held at 60 ° C. for a specified time. The emulsion was then cooled as quickly as possible to 40 ° C., 70 mg / mol of APMT was added and the emulsion was cooled and solidified.

Photographic results Each sample was placed on a support having an antihalation layer.
1.08 g / m ² cyan dye-forming coupler C-1 and 2.7 g / m 2
Coated with 0.85 g / m ² silver with ² gelatin. This layer
It was overcoated with 1.6 g / m ² gelatin and the entire coating was cured with bis (vinylsulfonylmethyl) ether at 1.75% by weight of the total coated gelatin.

Exposure was performed through a step wedge for 0.02 seconds with a 3000 K tungsten light source filtered through daylight V and Kodak Wratten ^™ 9 filters. Kodak a coating film Flexi color ^TM
The film was processed by a C-41 color negative developing method.

From Table XXIV it is clear that the spectral sensitizing dye combinations produce a higher level of response than when using the same amount of only one dye.

Example 34 This example demonstrates the use of blue, green and red spectrally sensitized high chloride
The photographic performance of the 0 ° tabular grain emulsion in the yellow, magenta and cyan dye forming layer units, respectively, is shown. This emulsion was then coated on a resin-coated paper support and developed.

Blue Sensitized Emulsion (B-SensEm) An iodochloride (0.05 mol% iodide) {100} tabular grain emulsion having an average grain ECD of 1.61 μm and an average thickness of 0.150 μm was used. The emulsion was washed by ultrafiltration and its pH and pCl were adjusted to 5.6 and 1.5, respectively. The emulsion was sensitized by the addition of the blue spectral sensitizing dye SS-1 followed by the addition of gold sulfide and heat ripening, followed by APMT.
Was added to the emulsion melt.

Green sensitized emulsion (G-SensEm) An iodochloride (0.05 mol% iodide) {100} tabular grain emulsion having an average grain ECD of 1.38 μm and an average thickness of 0.148 μm was used. The emulsion was washed by ultrafiltration and its pH and pCl were adjusted to 5.6 and 1.5, respectively. The emulsion was sensitized by the addition of the green spectral sensitizing dye SS-21 followed by the addition of gold sulfide and heat ripening, followed by APMT.
Was added to the emulsion melt.

Red-sensitized emulsion (R-SensEm) An iodochloride (0.05 mol% iodide) {100} tabular grain emulsion having an average grain ECD of 1.61 μm and an average thickness of 0.150 μm was used. The emulsion was washed by ultrafiltration and its pH and pCl were adjusted to 5.6 and 1.5, respectively. The emulsion was sensitized by the addition of the red spectral sensitizing dye SS-19, followed by the addition of gold sulfide and heat aging, followed by APMT.
Was added to the emulsion melt.

Dye-Forming Coupler Dispersions One of the dye-forming coupler dispersions shown in Table XXV was introduced as a disperse phase into one sample of a blue, green and red sensitized emulsion.

Solvent S-1 Dibutyl phthalate S-2 Tritolyl phthalate S-3 N, N-Diethyldodecaneamide S-4 Tris (2-ethylhexyl) phosphate S-5 2- (2-Butoxyethoxy) ethyl acetate S-6 2,5-Di-t-phenylphenol Photographic elements 34/1 to 34/12 Photographic elements were prepared by coating the following layers in the order described on a resin-coated paper support.

First layer Gelatin 3.23 g / m ² Second layer Gelatin 1.61 g / m ² Coupler dispersion (See Table XXIV) Emulsion (See Table XXIV) Third layer Gelatin 1.40 g / m ² Bis (vinylsulfonylmethyl) ether 0.14 g / m ² Photographic elements 34/13 to 34/22 Photographic elements were prepared by applying the following layers in the order described on a resin-coated paper support.

First layer Gelatin 3.23 g / m ² Second layer Gelatin 1.61 g / m ² Coupler dispersion (see Table XXV) Emulsion (see Table XXV) Third layer Gelatin 1.33 g / m ² 2- (2H-benzotriazole- 2-yl) -4,6-
Bis (1,1-dimethylpropyl) phenol 0.73g / m ² Tinuvin ^TM (Ciba - Geigy) 0.13 g / m ² 4th layer Gelatin 1.40 g / m ² bis (vinylsulfonyl methyl) ether 0.14 g / m ² Exposure and Development The photographic elements were given a step wedge exposure and developed at 35 ° C. as described below.

 Developing solution 45 seconds Bleaching-fixing 45 seconds Washing (running water) 1 minute 30 seconds Developing solution and bleach-fixing had the following composition.

Developer Water 700.00mL Triethanolamine 12.41g Blankophor REU ^™ (Mobay Corp.) 2.30g Lithium polystyrene sulfonate (30%) 0.30g N, N-diethylhydroxylamine (85%) 5.40g Lithium sulfate 2.70g N-II 2-[(4-amino-3-methylphenyl) ethylamino] ethyl} methanesulfonamide, sesquisulfate 5.00 g 1-hydroxyethyl-1,1-diphosphonic acid (60%)
0.81 g Potassium carbonate, anhydrous 21.16 g Potassium chloride 1.60 g Potassium bromide 7.00 mg Water was added to adjust 1.00 L to pH 10.4 ± 0.05 at 26.7 ° C.

Bleaching-fixing Water 700.00mL Solution of ammonium thiosulfate (56.4%) + ammonium sulfite (4%) 127.40g Sodium metabisulfite 10.00g Acetic acid (glacial acetic acid) 10.20g Ferric ammonium ethylenediaminetetraacetate (44%)
+ Ethylenediaminetetraacetic acid (3.5%) solution 110.40 g Water was added to adjust the pH to 6.7 at 1.00 L at 26.7 ° C.

Photographic results Cyan, magenta or yellow dyes were formed by development. The following photographic properties were measured. D-max (maximum density for light of a color complementary to the pigment color); D-min (minimum density); and sensitivity (relative log exposure required to produce a density of 1.0). These values for each example are given in Table XXVIII
Shown in

Table XXVIII shows the utility of high chloride {100} tabular grain emulsions with various couplers in dispersions commonly used for color paper reflection print materials.

Examples 35-37 These examples demonstrate the reduced high intensity reciprocity failure (HIRF) of the high chloride {100} tabular grain emulsions of the present invention when compared to high chloride cubic grain emulsions.

Example 35 A comparative cubic grain high chloride emulsion, hereinafter referred to as Emulsion 35 / C,
Precipitated by adding equimolar amounts of silver nitrate and sodium chloride into a well stirred reactor containing gelatin peptizer and thioether ripener. The resulting emulsion contained cubic grains having an average edge length of 0.74 µm.

An iodochloride (0.05 mol% iodide) {100} tabular grain emulsion according to the present invention was prepared wherein more than 50% of total grain projected area is occupied by tabular grains having {100} major faces. The average grain ECD was 1.55 μm and the average grain thickness was 0.155 μm. The emulsion was washed by ultrafiltration and its pH and pCl were adjusted to 5.6 and 1.6, respectively.
This emulsion is hereinafter referred to as emulsion 35 / T.

Each emulsion was divided into separate aliquots for spectral and chemical sensitization. A part of the emulsion 35 / C was optimally sensitized by the addition of gold sulfide, the temperature was raised to 60 ° C,
MT, potassium bromide and one of the blue spectral sensitizing dyes SS-1, SS-50 or SS-51 were added. These emulsion portions are hereinafter referred to as 35 / C1, 35 / C2 and 35 / C3, respectively. A portion of emulsion 35 / T was optimally sensitized by the addition of SS-1, SS-50 or SS-51 followed by the addition of gold sulfide and thermal ripening, after which APMT was added to the melt. The portions of these emulsions are referred to as 35 / T1 and 35 / T respectively.
Say 2 and 35 / T3.

All emulsions 1.8 m with yellow dye-forming coupler
g / dm ² of silver and 7.5 mg / dm ² of gelatin were coated on a resin-coated paper support to form a blue recording layer unit. Both the green and red recording layer units were also coated to form a multicolor pack.

Samples of the multicolor pack were subjected to isoexposure for 10 ^-1 and 10 ^-5 seconds using an optical reciprocity sensitometer. The exposed sample was developed with Kodak RA-4 ^™ color print developer. Photographic sensitivity was taken at a minimum density plus 0.35 density.

 The results are summarized in Table XXIX.

From Table XXIX, higher sensitivity and reduced HIRF of the emulsion 35 / T sample are apparent.

Example 36 A comparative cubic grain high chloride emulsion, hereinafter referred to as Emulsion 36 / C,
Precipitated by adding equimolar amounts of silver nitrate and sodium chloride into a well stirred reactor containing the low methionine gelatin peptizer. 0.42μ in the resulting emulsion
Cubic particles with an average edge length of m were included.

A silver iodochloride (0.05 mol% iodide) {100} tabular grain emulsion according to the present invention was prepared wherein more than 50% of total grain projected area is occupied by tabular grains having {100} major faces. The average particle ECD was 1.38 μm and the average particle thickness was 0.148 μm. The emulsion was washed by ultrafiltration and its pH and pCl were adjusted to 5.6 and 1.6, respectively.
This emulsion is hereinafter referred to as Emulsion 36 / T.

Each part of emulsion 36 / C and 36 / T was sensitized by addition of gold sulfide and spectral sensitizing dye SS-21 and heat ripening, followed by
APMT and potassium bromide were added. The sensitized portion of the emulsion was coated as described above in Example 35, except that the sensitized emulsion portion was mixed with a magenta dye-forming coupler and coated in the same manner as the green recording layer unit of the multicolor pack. , Exposed and developed. The results are summarized in Table XXX.

From Table XXX, the higher sensitivity and reduced HIRF of the emulsion 36 / T sample is apparent.

Example 37 A comparative cubic grain high chloride emulsion, hereinafter referred to as emulsion 37 / C,
Precipitated by adding equimolar amounts of silver nitrate and sodium chloride into a well stirred reactor containing gelatin peptizer and thioether ripener. The resulting emulsion contained cubic grains having an average edge length of 0.40 µm.

A silver iodochloride (0.05 mol% iodide) {100} tabular grain emulsion according to the present invention was prepared wherein more than 50% of total grain projected area is occupied by tabular grains having {100} major faces. The average grain ECD was 1.61 μm and the average grain thickness was 0.15 μm. The emulsion was washed by ultrafiltration and its pH and pCl were adjusted to 5.6 and 1.6, respectively.
This emulsion is hereinafter referred to as emulsion 37 / T.

Addition of gold sulfide and thermal ripening of part of emulsion 37 / C, followed by APM
It was optimally chemically and spectrally sensitized by the addition of T, potassium bromide and the red spectral sensitizing dye SS-19. A portion of Emulsion 37 / T was optimally chemically and spectrally sensitized in the same manner as Emulsion 37 / C.

The sensitized portion of the emulsion was coated as described above in Example 35, except that the sensitized emulsion portion was mixed with a cyan dye-forming coupler and coated in the same manner as the multicolor pack red recording layer unit. , Exposed and developed. The results are summarized in Table XXXI.

From Table XXXI, the higher sensitivity and reduced HIRF of the emulsion 37 / T sample is evident.

Although the present invention has been described in detail with particular reference to preferred embodiments thereof, it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

 Hereinafter, specific embodiments of the present invention will be listed.

1. Tabular grains having a thickness of less than 0.3 µm and exhibiting {100} major faces with an adjacent edge ratio of less than 10 occupy at least 50% of the total grain projected area, and have iodides therein at their nucleation sites. And producing a silver halide emulsion containing at least 50 mol% chloride, comprising: (1) introducing a silver salt and a halide salt and a dispersing medium into a continuous double jet reactor, wherein Causing nucleation of tabular grains in the presence of iodide with chlorides comprising at least 50 mole percent of the halides
And maintaining the pCl of the dispersion medium in the range of 0.5 to 3.5, and (2) following the nucleation, subjecting the emulsion from a continuous double jet reactor to conditions maintaining {100} major faces of the tabular grains. Completing the particle growth in the receiving reaction vessel.

2. The method of embodiment 1, wherein the bromide ion is present in the dispersion medium following particle nucleation.

3. essentially chloride ions and iodides wherein the pCl of the dispersion medium is in the range of 1.0 to 1.3 and the gelatino-peptizer present has a methionine content of less than 30 micromol / g of peptizer The method according to embodiment 1, wherein the particle nucleation is performed in the presence of a halide ion composed of an ion.

4. Essentially chloride ions and iodides, wherein the pCl of the dispersion medium is in the range of 1.5 to 2.5 and the gelatino-peptizer present has a methionine content of less than 12 micromoles per gram of peptizer The method according to embodiment 3, wherein grain nucleation is performed in the presence of a halide ion composed of an ion.

5. The method according to embodiment 1, wherein the silver salt solution and the halide salt solution are introduced into the dispersion medium during grain nucleation and growth.

6. The method of embodiment 5, wherein the addition of the silver salt solution and the halide salt solution is stopped after grain nucleation to allow Ostwald ripening of the grain nuclei and then restarted.

7. The method of embodiment 6, wherein the chloride salt solution and the iodide salt solution are introduced into the dispersion medium during grain nucleation.

8. The method according to embodiment 7, wherein the addition of the silver salt solution and the halide salt solution is stopped to cause Ostwald ripening of the grain nuclei, and then the introduction of the salt solution is restarted. .

9. The method of embodiment 1, wherein the grain growth is continued until the portion of the tabular grains has an average aspect tabularity greater than 25.

10. The method according to embodiment 1, wherein the silver halide ripening agent is introduced into the dispersion medium in the growth reaction vessel.

11. The method according to embodiment 10, wherein the ripening agent is a thioether.

12. Embodiment 1 in which the thioether is a crown thioether
Method according to 1.

13. The method according to embodiment 10, wherein the ripening agent is a thiocyanate.

14. The method according to embodiment 10, wherein the ripening agent is methionine.

15. The method of embodiment 10, wherein the ripening agent contains a primary or secondary amino moiety.

16. The method according to embodiment 10, wherein the ripening agent is an imidazole ripening agent.

17. The method according to embodiment 10, wherein the ripening agent is glycine.

18. The method according to embodiment 1, wherein bromide ions are present in the reaction vessel during the grain growth at a concentration of 0.5 to 15 mol%.

19. The method according to embodiment 18, wherein bromide ions are present in the reaction vessel during particle growth at a concentration of 1 to 10 molar.

20. Embodiment 1 in which iodide ions are present in the reaction vessel during grain growth at a concentration of 0.001 mol% to less than 1 mol%
The described method.

21. The method according to embodiment 1, wherein the precipitation occurs in a pH range from 2.0 to 8.0.

22. The method of embodiment 21, wherein the precipitation occurs at a pH of less than 7.0.

23. The method according to embodiment 22, wherein precipitation occurs in a pH range of 2.0 to 5.0.

24. The method of embodiment 1, wherein the precipitation is effected in the presence of a mild oxidizing agent selected from the group consisting of mercury salts, alkali tetrahaloaurates and elemental sulfur releasing compounds.

──────────────────────────────────────────────────続 き Continuing the front page (72) Inventor Hartsel, Debralin United States of America, New York 14612, Rochester, Snug Harbor Court 42 (72) Inventor Black, Donald Lee United States of America, New York 14580, Webster, High Tower Way 803 (72) Inventors Antoniades, Michael George United States, New York 14618, Rochester, Birmingham Drive 15 (72) Inventor Zauer, Allen K-Chan United States of America, New York 14450, Fairport, Country Corner Lane 71 (72) Inventor Chan, Yun Chair United States, New York 14625, Penfield, Cardgun Square 43 (56) Document JP-flat 6-59360 (JP, A) JP flat 6-242536 (JP, A) (58 ) investigated the field (Int.Cl. ^7, DB name) G03C 1/015 G03C 1/035

Claims (6)

(57) [Claims] (1) a thickness of less than 0.3 μm and an adjacent edge ratio of 1
Tabular grains exhibiting a {100} major surface of less than 0 occupy at least 50% of the total grain projected area and contain iodide and at least 50 mol% chloride at their nucleation sites Comprising the steps of: (1) introducing a silver salt and a halide salt and a dispersion medium into a continuous double jet reactor, and adding iodide together with a chloride that accounts for at least 50 mol% of the halide present in the dispersion medium. Causing nucleation of tabular grains in the presence of a chloride and maintaining the pCl of the dispersion medium in the range of 0.5 to 3.5; and (2) following nucleation, {100} primary Completing the grain growth in a reaction vessel receiving the emulsion from a continuous double jet reactor under conditions that maintain the surface. 2. The method of claim 1 wherein the pCl of the dispersion medium is in the range of 1.0 to 3.0 and the gelatino-peptizer present has a methionine content of less than 30 micromoles per gram of peptizer, essentially chloride ions. 2. The method according to claim 1, wherein the grain nucleation is carried out in the presence of a halide ion comprising iodide and iodide ions. 3. The method of claim 1 wherein the silver salt solution and the halide salt solution are introduced into the dispersion medium during grain nucleation and growth. 4. The method of claim 1 wherein grain growth is continued until said portion of the tabular grains has an average aspect tabularity greater than 25. 5. The method according to claim 1, wherein the silver halide ripening agent is introduced into a dispersion medium in a growth reaction vessel. 6. The method according to claim 1, wherein iodide ions are present in the reaction vessel during grain growth at a concentration of from 0.001 mol% to less than 1 mol%.