JPH06301131A - Oligomer-reformed platelike grain emulsion - Google Patents

Abstract

PURPOSE: To provide an emulsion into which the adjacent cation crystal lattice position particle dopants specific to the novel particles extremely effective for improving photographic performance are incorporated. CONSTITUTION: This radiation sensitive photosensitive emulsion contains silver halide particle groups contg. chloride at least at 50mol% of the total silver forming the normal of a grain group projection plane. At least 50% of the total gain projection area is occupied by the tabular grains (1) which are partitioned by main faces 100} having <10 adjacent edge ratio, (2) which respectively have at least 2 aspect ratio and (3) which contains in average at least a pair of metallic ions selected from the fifth 5 and sixth periods of the group 8 in the adjacent cation positions of these crystal lattices.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a radiation-sensitive silver halide emulsion and a method for preparing the same.

[0002]

2. Description of the Related Art In the 1980s, the sensitivity-granularity relationship was improved, at the absolute standard, and as a function of binder curing, the coating power was increased, the developability was faster, the temperature stability was increased, and the image sensitivity was increased. A wide range of photographic advantages, such as increased separation of inherent sensitivity and spectral sensitization and improved image sharpness in both single emulsion layer and multiple emulsion layer formats, were obtained by using tabular grain emulsions. Significant progress has been made in silver halide photography based on what it has found to be attainable.

The tabular grains account for at least 5 of the grain projected area.
At 0%, the emulsion is generally understood to be a "tabular grain emulsion". A grain is generally considered to be a tabular grain if the equivalent circular diameter (ECD) ratio of the grain to its thickness is at least 2. The equivalent circular diameter of a particle is the diameter of a circle having an area equal to the projected area of the particle. The term "medium aspect ratio tabular grain emulsion" refers to an emulsion having an average tabular grain aspect ratio in the range of 5-8. The term "high aspect ratio tabular grain emulsion" refers to an emulsion having an average tabular grain aspect ratio of greater than 8. The term "thin tabular grains" is generally understood to be tabular grains having a thickness of less than 0.2 µm. The term "extremely thin tabular grains" is generally understood to be tabular grains having a thickness of 0.06 µm or less. The term "high chloride" refers to particles containing at least 50 mol% chloride based on silver. For mixed halogen-containing particles, the halogens are named in order of increasing molarity. For example, silver iodochloride contains a higher concentration of chloride than iodide.

The overwhelming majority of tabular grain emulsions contain irregular octahedral tabular grain emulsions. Octahedral grains have eight identical crystal faces (each in a different {111} crystal face). The tabular irregular octahedron has two or more parallel twin planes that separate the two main grain faces in the {111} crystal face. The {111} major surface of the tabular grain has triple symmetry and shows a triangle or a hexagon. The tabular shape of the grains creates the preferred edge sites in silver halide deposition with the result of lateral grain growth (if necessary) with a slight increase in thickness after incorporation of parallel twin planes. It is generally accepted that it comes from twin planes.

Tabular grain emulsions have been used to advantage in a wide variety of photographic and radiographic applications, while the need for parallel twin plane formation and {111} crystal faces has led to emulsion preparation and It raises the issue of limiting both use. These drawbacks are most apparent when considering tabular grains containing significant chloride concentrations. It is generally accepted that silver chloride grains prefer to produce tetragonal cubic grains (ie the grains are separated by six identical {100} crystal faces). In silver chloride emulsions, tabular grains bounded by {111} planes often revert to nontabular shapes unless morphologically stabilized.

Tabular grain silver bromide emulsions have been available for a long time in 19
Wey, U.S. Pat. No. 4,399,215, known in the art in the eighties, produced the first tabular grain silver chloride emulsions. The tabular grains are {11
It was a twin type, showing a triple symmetrical main surface in the 1} crystal plane. The ammoniacal double-jet precipitation technique was used. The tabular grains were thicker than the silver bromide and silver bromoiodide tabular grain emulsions of the same era, as the ammonia ripening agent thickened the tabular grains. In order to achieve ammonia ripening, it was also necessary to precipitate the emulsion at a relatively high pH (known as minimum density enhancement (fog) in high chloride emulsions). Furthermore, both bromide and iodide ions were removed from the tabular grains early in their formation to prevent the desired tabular grain shape from collapsing.

US Pat. No. 4,414,306 to Wey et al.
The specification developed a twinning process for preparing silver chlorobromide emulsions containing up to 40 mol% chloride, based on total silver.
This method of preparation did not successfully extend high chloride emulsions. The highest average aspect ratio reported in the examples was 11. Maskasky US Patent No. 4,
No. 400,463 (hereinafter, Maskasky I
Precipitates high chloride emulsions containing tabular grains with parallel twin planes and {111} major crystal faces, which has the important advantage of allowing inclusion of substantially significant other halides. Developed the method. This method uses a specially selected synthetic polymer peptizer as its action {1
11} was to be used in combination with a grain growth modifier that promotes the formation of crystal planes. Adsorbed aminoazaindene (preferably adenine) and iodide ions have been disclosed as useful grain growth modifiers.

Maskasky US Pat. No. 4,71
No. 3,323 (hereinafter referred to as Maskasky II) describes an aminoazaindene growth modifier and a maximum of 3
A high chloride emulsion containing tabular grains having parallel twin planes and {111} major crystal faces was prepared by using a gelatin peptizer containing 0 μmol / g methionine. Advanced significantly. If the methionine content of the gelatin peptizer is undesirably high, it can be easily reduced by treatment with a strong oxidant (ie, alkylating agent, King et al., US Pat. No. 4,942,120). Because it can be done, Maskasky
II was within the reach of the art to place high chloride tabular grains encapsulating the key bromide and iodide ions prepared, including conventional, commonly available peptizers.

Maskasky I and II stimulated further studies of grain growth modifiers that allowed the preparation of high chloride emulsions of similar tabular grain content: di (hydroamino) as a grain growth modifier. Tafa with azine
No. et al., U.S. Pat. No. 4,804,621; Takada et al., U.S. Pat. No. 4,783,398, using heterocycles with divalent sulfur ring atoms; spectral sensitizing dyes and heterocycles; US Pat. No. 4,9, Nishikawa et al. Using a divalent sulfur atom containing an acyclic compound.
52,491; as well as US Pat. No. 4,983,5 to Ishiguro et al. Using organic bis quaternary amine salts.
No. 08 specification.

Bogg US Pat. No. 4,063,951
The specification first reported a tabular grain emulsion in which the tabular grains had parallel {100} major crystal faces. Bogg's tabular grains exhibited square or rectangular major faces (thus lacking the triple symmetry of conventional tabular grain {111} major crystal faces). In one example, Bogg is 4: 1 to 1:
The ammonia ripening method was used to prepare silver bromoiodide tabular grains having aspect ratios of 1. The highest aspect ratio grains (grain A in Figure 3) were only 4, and the average aspect ratio of this emulsion was reported to be 2. Bogg states that this emulsion can contain less than 1% iodide and describes only a 99.5% bromide 0.5% iodide emulsion. Attempts to prepare tabular grain emulsions by the Bogg procedure were unsuccessful.

Mignott US Pat. No. 4,386,1
No. 56 shows an improvement of Bogg in the advantage of avoiding ammoniacal ripening in the preparation of silver bromide emulsions containing tabular grains having square and rectangular major faces. Mignot specifically requires ripening without silver halide ripening agents other than bromide ions (eg thiocyanate, thioether or ammonia).

Endo and Okaji's "An Empiric
al Rule to Modify the Habit ot Silver Chloride to
form Tabular Grains in an Emulsion '', The Journal
of Photographic Science, Vol. 36, pp. 182-188, 1988, discloses silver chloride emulsions prepared in the presence of thiocyanate ripening agent. Emulsion preparation according to the disclosed procedure produces mixed {111} and {100}
Emulsions were formed containing a small amount of tabular grains within the general grain population exhibiting facets.

Mumaw and Hwugh, "Silver H
alide Precipitation CoalescenceProcess '', Journal
of Imaging Science, Volume 30, No. 5, 1986
September / October, pages 198-299, is essentially E
Accumulate in ndo and Okaji (particularly directly related to section IV-B). Symposium: Turin 19
63, C.I. Semero and Mazzucato
Editor Photographic Science, Focal Press, pages 52-55, discloses ripening of cubic grain silver chloride emulsions at 77 ° C for several hours. During ripening tabular grains appear and the original cubic grains are depleted by Ostwald ripening. After 3 hours of ripening, the tabular grains accounted for only a small portion of the total grain projected area, with only a few tabular grains having a thickness of less than 0.3 μm, as illustrated by the Comparative Examples below. It was In further studies beyond the teachings actually provided, extended ripening removed a large number of smaller cubic grains, but also downgraded a large number of tabular grains to thicker shapes.

Japanese Unexamined Patent Publication No. 02-024643 (published on January 26, 1990) was cited in the PCT International Search Report as having a direct relation with the tabular grain structure described in the claims. Irrelevant. The claims are directed to negative-working emulsions containing hydrazide derivatives and tabular grains having equivalent circular diameters of 0.6 to 0.2. Only conventional tabular grain preparations are disclosed, and only silver bromide and silver bromoiodide emulsions are exemplified.

US Pat. No. 5,024,9 to Evans et al.
No. 31 is a radiation-sensitive halogenation showing a face-centered cubic crystal lattice structure containing on average at least a pair of metal ions selected from the 5th and 6th periods of Group 8 at adjacent cation positions of the crystal lattice. A silver halide photographic emulsion comprising silver grains is disclosed.

[0016]

SUMMARY OF THE INVENTION In one aspect, the present invention provides a radiation-sensitive silver halide grain population comprising at least 50 mole percent chloride based on total silver forming a grain population projection normal. An emulsion in which at least 50% of the total grain projected area is (1) bounded by {100} major faces having adjacent edge ratios less than 10.
Tabular grains each having an aspect ratio of at least 2 and (3) averaging at least a pair of metal ions selected from the 5th and 6th periods of Group 8 at adjacent cation positions in their crystal lattice. Is directed to radiation-sensitive emulsions characterized by being occupied by.

In another aspect, the present invention is a radiation-sensitive emulsion comprising a dispersion medium and silver halide grains, wherein at least 50% of the total grain projected area has (1) an adjacent edge ratio of less than 10. Partitioned by {100} major faces, (2) each having an aspect ratio of at least 2, and (3) at least selected from Periods 5 and 6 of Group 8 at adjacent cation positions in their crystal lattice. A radiation-sensitive emulsion characterized in that it contains, on average, a pair of metal ions and is (4) occupied by tabular grains containing iodide and at least 50 mol% chloride at the nucleation sites inside. , (A) in the presence of iodide with chloride accounting for at least 50 mol% of the chloride present in the dispersion medium, and the pCl of the dispersion medium being 0.5-3.
Maintaining a range of 5 to introduce silver and halide circles into the dispersion medium such that tabular grain nucleation occurs, (b) following nucleation, the tabular grain {100}
Completing the grain growth under conditions that maintain the major surface, and (c) at least one of steps (a) and (b), in a dispersion medium, of a Group 8 Group 5 or 6 period metal. Introducing an oligomer, wherein each oligomer comprises at least two metal ions, and at least two metal ions are incorporated on average into each particle at adjacent cation positions. The present invention is directed to a method of preparing a radiation-sensitive emulsion prepared by the steps of:

[0018]

The present invention has been facilitated by the discovery of a novel method for producing tabular grains. Parallel twin planes are formed to produce tabularity, thereby {111}
In the high chloride nucleation stage, which maintains the chloride ions of the solution within the selected pCl range, instead of introducing parallel twin planes into the grains to produce tabular grains with major faces. Has been found to result in the formation of tabular grain emulsions in which the tabular grains are bounded by {100} crystal faces.

The present invention combines novel grain-specific adjacent cation crystal lattice position grain dopants that are very effective in improving photographic performance. Thus, not only is the practice of the present invention representing the discovery of a novel method for preparing tabular grain emulsions, the emulsions made by that method are also novel. The present invention is within the reach of the art to find tabular grains bounded by {100} crystal faces with halide content, dopant content and halide configuration, and grain thicknesses heretofore unrealized. Put. The present invention provides ultrathin tabular grain emulsions of grains bounded by {100} crystal faces. The present invention, in its preferred form, provides intermediate aspect ratio tabular grain high chloride emulsions which exhibit high levels of grain stability. Unlike high chloride tabular grain emulsions in which the tabular grains have {111} major faces, the emulsions of this invention incorporate a morphological stabilizer that is adsorbed on the major faces of the grains and maintains its tabular shape. do not need. Finally, they can be applied to silver chloride and silver bromochloride emulsions, while at the same time they can be prepared by various precipitation procedures that do not require the presence of iodide during grain nucleation.

Photographically useful radiation-sensitive emulsions of this invention comprise a dispersion medium and silver halide grains.
This emulsion contains a population of high chloride grains. At least 50% of the total particle projected area of the high chloride particle population is (1)
Separated by {100} major faces having adjacent edge ratios of less than 10, (2) each having an aspect ratio of at least 2, and (3) a fifth group 8 at adjacent cation positions in the crystal lattice. And tabular grains containing an average of at least one pair of metal ions selected from 6 periods.

The identification of emulsions satisfying the requirements of the invention and the key selection parameters can be better evaluated by considering typical emulsions. FIG. 1 is a shaded photomicrograph of a carbon grain replica of an emulsion, prepared as described in Example 1 below. It can immediately be clearly seen from Figure 1 that most particles have orthogonal rectangular (square or rectangular) faces. The orthogonal square shapes of the grain faces indicate that they are {100} crystal faces.

It is recognized that the projected areas of a few grains in the sample that do not have square or rectangular faces are included in the calculation of the grain collective projected areas, but these grains are clearly tabular with {100} major faces. Is not part of a spheroidal population.
Some particles are observed to be needle-shaped or rod-shaped particles (hereinafter referred to as rods). These grains can be excluded from the desired tabular grain population based on their high edge length ratio because their length in one direction is more than 10 times longer than the length in the other direction. The projected area occupied by the rods is small, but in the presence of the rods, their projected area is considered to be the particle population projected area to be measured.

The remaining grains all have square or rectangular major faces (indicating {100} crystal faces). To identify tabular grains, it is necessary to measure the ratio of ECD to core thickness (t) (ie, ECD / t) for core grains. The ECD is determined by measuring the projected area (product of edge length) of the upper surface of each grain. The ECD of the particle is calculated from the projected area of the particle. Grain thickness is usually measured by obliquely illuminating a population of particles that produces individual grain projections. From the information on the angle of illumination (shadow angle), it is possible to calculate the particle thickness from the measurement of the shadow length. Grains having square or rectangular faces and grains each having an ECD / t ratio of at least 2 are tabular grains having {100} major faces. {10
An emulsion is a tabular grain emulsion when the projected area of the 0} tabular grains account for at least 50% of the projected area of the grain population.

In the emulsion of FIG. 1, tabular grains account for greater than 50 percent of total grain population projected area. From the tabular grain definition procedure, the average tabular grain aspect ratio was 2
It is clear that we can only approach (minimum). In fact, the tabular grains used in this invention typically exhibit an average aspect ratio of 5 or greater (greater than 8, preferably with high average aspect ratio). That is,
The preferred emulsions used in this invention are high aspect ratio tabular grain emulsions. A particularly preferred emulsion has a mean tabular grain population aspect ratio of at least 12, and
Optionally at least 20. Typically, tabular grain populations have average aspect ratios of up to 50,
Higher aspect ratios of 100, 200 or higher can be achieved. Emulsions within the contemplation of the invention in which the average aspect ratio approaches the minimum average aspect ratio limit of 2 provide cubic grains with a volume to surface ratio of 200%.

The tabular grain population can exhibit any grain thickness compatible with the average aspect ratios already noted herein. However, especially when the selected tabular grain population exhibits a high average aspect ratio, the grains contained in the selected tabular grain population are further reduced to a thickness of less than 0.3 .mu.m, and optimally 0. It is preferable to limit to those exhibiting a thickness of less than 2 μm. It is understood that the aspect ratio of a tabular grain can be limited either by limiting its equivalent circular diameter or increasing its thickness. Therefore, when the average aspect ratio of the tabular grain population is in the range of 2 to 8, the tabular grains occupying at least 50% of the projected area of the grain population also have a grain thickness smaller than 0.3 μm or smaller than 0.2 μm, respectively. It can exhibit a thin grain thickness. Nevertheless, for aspect ratios in the range of 2-8, there are particular photographic applications that can be obtained with higher tabular grain thicknesses. For example, in the construction of a blue recording emulsion of maximum achievable sensitivity, it is explicitly expected that average 1 μm or even higher tabular grain thicknesses are acceptable. This is because the eyes have little sensitivity to blue records, and therefore higher levels of image granularity (noise) can be tolerated without problems. There is an additional motivation to use larger particles in the blue record, which is that it is sometimes difficult to match the highest achievable sensitivity of the blue record to the green and red records. The source of this difficulty is the lack of blue photons in sunlight. Energy-based sunlight shows an equal proportion of blue, green, and red light, while at shorter wavelengths, photons have higher energy. Thus, for photons, the distribution based on daylight is slightly blue deficient.

Preferably, the tabular grain population exhibits a major surface edge length ratio of less than 5, optimally less than 2. The closer the principal face edge length ratio is to 1 (ie, equal to the edge length), the less probable the rod population is to be significantly present in the emulsion. In addition, tabular grains with smaller edge lengths are believed to be less sensitive to pressure desensitization.

In one particular preferred form of the invention the tabular grain population accounting for at least 50% of the grain population projected area is also provided by tabular grains representing 0.2 μm. In other words, in this example, the emulsion is a thin tabular grain emulsion. Surprisingly, ultrathin tabular emulsions have been prepared which meet the requirements of the present invention. Ultrathin tabular grain emulsions are those in which the selected tabular grain population is composed of tabular grains having an average thickness of less than 0.06 μm.
Prior to the inventive preparation technique, only chloride-containing ultrathin tabular grain emulsions exhibiting a cubic lattice structure known in the art contained tabular grains bounded by {111} major faces. In other words, it was considered essential to form tabular grains by the mechanism of parallel twin plane incorporation to achieve ultrathin dimensions. The emulsions prepared in accordance with the present invention can be prepared so that the tabular grain population has a mean thickness of at least 0.02 μm, and even 0.01 μm. Ultrathin tabular grains have extremely high volume to surface ratios. This allows the ultrathin particles to facilitate photographic processing. Furthermore, when spectrally sensitized, the ultrathin grains show a much higher sensitivity ratio in the sensitized spectral region compared to the original spectral region of sensitivity. For example, the ultrathin tabular grain emulsions described herein have quite negligible blue sensitivity levels and, therefore, produce minimal blue contamination in photographic products when placed in a position to receive blue light. A green or red record can be provided to indicate.

A distinctive feature of tabular grain emulsions from other emulsions is the ratio of thickness (t) to grain ECD. This relationship is represented by the amount of aspect ratio. Another quantity believed to more accurately assess the importance of tabular grain thickness is tabularity: T = ECD / t ² = AR / t, where T is tabularity AR is the aspect ratio; EC
D is the equivalent circular diameter (μm); and t is the particle thickness (μ
m)).

The high chloride tabular grain population accounting for 50% of the grain population projected area preferably exhibits a tabularity of greater than 25, and most preferably greater than 100. Since tabular grain populations can be ultrathin, it is clear that extremely high tabularities (up to 1000 and above) are within the scope of the invention.

The tabular grain population can represent an average ECD of any useful size. Photographically practical average ECD's of less than 10 μm are contemplated, but for many photographic applications the average ECD's rarely exceed 6 μm. Within the ultrathin tabular grain emulsion satisfying the requirements of the invention, medium aspect ratios can be provided with ECD's of 0.10 μm and smaller tabular grain populations. As is generally understood by those skilled in the art, emulsions with a selected tabular grain population with a larger ECD are advantageous in achieving relatively high levels of photographic speed. A selected tabular grain population with a smaller ECD at the same time is advantageous in achieving low levels of granularity.

The tabular grain population satisfying the parameters set forth herein is at least 5 of the grain population projected area.
As long as it makes up 0%, the desired grain population for photography is available. It is noted that the beneficial properties of the emulsions used in this invention increase as the proportion of tabular grains having {100} major faces increases. Preferred emulsions according to the present invention have at least 70 percent, and optimally at least 90 percent of total grain projected area occupied by tabular grains having {100} major faces. It is clear that the selection of grades defining tabular grains provides emulsions satisfying the grain description herein that the tabular grains extend to sufficient tabular grains accounting for 70% or even 90% of total grain projected area. Expected.

To the extent that tabular grains having the desired properties set forth herein account for the requisite proportion of grain population projected area, the remainder of the grain population projected area will account for any combination of coprecipitated grains. Can also be occupied by.
Of course, it is conventional in the art to formulate emulsions to achieve particular photographic purposes. Formulated emulsions satisfying the tabular grain rating required by at least one component emulsion are clearly envisioned.

When tabular grains satisfying the tabular grain population requirements do not account for 50% of the grain population projected area, the emulsion does not meet the requirements of the invention and is generally photographically inferior. It is an emulsion. In many applications, especially those requiring spectral sensitization, those requiring rapid processing and / or those seeking to minimize silver content, many or all of the tabular grains are relatively Thick emulsions (eg, emulsions containing a high proportion of tabular grains having a thickness greater than 0.3 µm) are photographically inferior.

More generally, inferior emulsions which do not meet the requirements of this invention have an excessive proportion of the grain population projected area occupied by cubic, twinned tabular grains and rods. . Such an emulsion is represented in FIG. Most of the projected area of grains is occupied by cubic grains. The rod population is also much more pronounced than in FIG. Some tabular grains are present, but they account for only a small percentage of the total grain projected area.

The tabular grain emulsion of FIG. 1 which satisfies the requirements of the invention and the predominantly cubic grain emulsion of FIG. 2 were prepared under the same conditions except iodide treatment during nucleation. Figure 2
1 is a silver chloride emulsion, and the emulsion of FIG. 1 additionally contains a small amount of iodide introduced during grain nucleation.
The tabular grains described above which account for at least 50% of the total grain projected area, and preferably all grains produced by similar precipitation, contain at least one pair of metals of Group 8, 5 and 6 of the Periodic Table. On average in adjacent cation positions in the crystal lattice of. "The 8th, 5th and 6th periods" below
Is also referred to as "8 group 5/6" for brevity.

The present invention provides that when adjacent cation positions in the face-centered cubic crystal structure of a particle are occupied by Group 8 5/6 metal ions, they have no mechanism to achieve adjacent cation lattice arrangement. Other than the same 8 groups 5 /
It is based on the finding that it has a disproportionately large effect on photographic performance as compared to that explained by photographic emulsions in which six metal ions are similarly introduced. A pair of, on average, adjacent Group 8 5/6 metal ions incorporated into the crystal lattice of the photosensitive grains of the emulsion have the effect of enhancing photographic performance, and at least 5 pairs of grains of the photosensitive grains on average. It is preferred to incorporate adjacent Group VIII 5/6 metal ions incorporated into the lattice, preferably at least 10 pairs. The average incorporation of pairs can be determined solely by the number of light sensitive silver halide grains present in the emulsion, by halving the number of incorporated metal ions. The number of grains is determined from knowledge of the average grain size, grain shape, and the halogen and silver content of the emulsion. The actual distribution of Group 8 5/6 metal ions within the particles can be expected to follow a Poisson error function distribution with an average metal ion incorporation consistent with its distribution pattern.

The incorporation of a minimum of Group 8 5/6 metal ions per particle satisfying the requirements of the present invention is well above the minimum concentration level of Group 8 5/6 metal ions taught by the art to be effective. Down. For example, Smit
H and Trivelii US Pat. No. 2,448,0
No. 60 describes 0.8 mg of Group 8 5 per 100 g of silver.
A minimum concentration of / 6 metal coordination complex is disclosed. 1 per particle
When there are 00 Group 8 5/6 metal ions in the emulsion of the invention, the concentration of coordination complex (mg) per 100 g of silver is still at the minimum level of 1 as taught by Smith and Trivelii. Less than / 3.
Emulsions with adjacent pairs of Group 8 5/6 metal ions in a concentration range of 2, 10 or 20 Group 8 5/6 metal ions per grain, up to 100 Group 8 5/6 metal ions and above, By comparison with conventional emulsions having random crystal lattice positions of Group 8 5/6 metal ions, excellent photographic enhancement was achieved with emulsions satisfying the requirements of the invention.

In order to achieve the maximum photographic effect,
When a sufficient number of adjacent pairs of Group 8 5/6 metal ions are introduced into the particle, no further objectives are achieved by further increasing the proportion of Group 8 5/6 metal ions. However, the present invention is directed to the 8th family 5/6 taught in the art.
It does not stop the introduction of Group 8 5/6 metal ions, wholly or only partially, as pairs of adjacent lattice positions, up to the maximum effective concentration level of metal ion incorporation.

The Group 8 metal ions from the 5th period are Smi
Th and Trivelii concentration limits (about 40 mg /
(Less than 100 gAg), the elemental calculation is
It is only necessary to observe that there are only about 4 atoms of Group 5 Group 5 metal per 10,000 atoms of silver. If Group 8 metal ions from Period 6 are selected, this number is reduced by half, up to about 2 atoms per 10,000 silver atoms. Smith and Trivelii indicate a maximum of less than about 20 mg / 100 g Ag, ie, only about 2 atoms of Group 5 Group 8 metal per 10,000 atoms of silver, or 1 atom of Group 6 metal. 0.8mg / 100gAg, only 10 silver at the minimum level
About 8 atoms of Group 5 Group 8 metal, or 4 atoms of Group 6 Group 6 metal per 0,000 atoms are present in the emulsions of Smith and Trivelii. Therefore, 8 group 5
Adjacent cation lattice placement of the / 6 metal ion is, rarely and by any means, Smith and Triveli.
It is not achieved by using hexa coordination complexes each containing a single Group 8 5/6 metal ion, as taught by i.

A hexacoordination complex in which the adjacent cation position of the Group 8 5/6 metal ion in the face-centered cubic lattice structure of the silver halide grain contains at least two Group 8 5/6 metal ions in the emulsion. It has been discovered that this is achieved by introducing While it is known that the polymeric and oligomeric hexacoordination complexes have more Group 8 5/6 metal ions, those oligomers containing up to about 20 Group 8 5/6 metal atoms are preferred. Particularly preferred are oligomers containing about 6-10 Group 8 5/6 metal atoms. The oligomer coordination complex comprises two or more Group 8 5/6 metal atoms bound by a bridging ligand. For example, the following compounds are conceivable: (I) R ₂ MX ₆ (wherein R represents hydrogen, an alkali metal, or ammonium, and M is a Group 8, Group 5 or 6 metal (ie ruthenium). , Rhodium, palladium, osmium, iridium, or platinum), and X represents a halogen atom) When the compound of formula I above is dissolved, it separates into an anionic hexacoordination complex satisfying the formula: To do.

(II) MX ₆ (wherein M represents a Group 8, Group 5 or 6 metal, and X represents a halogen ligand) The six halogen ligands are halide ions. Are arranged around a Group 8 5/6 metal atom in the same manner as they are arranged around a silver ion in the face centered crystal lattice structure of a silver halide grain. Image of x, y and z axis crossings perpendicular to each other at the Group 8 5/6 metal atom, two ligands are located at equal intervals from the Group 8 5/6 metal atom along each of these three axes. There is. The corresponding anionic hexacoordination complex containing two Group 8 5/6 metal atoms is represented by the formula: (III) M ₂ L ₁₀ (wherein M is as previously defined and L
Represents halogen or other bridging ligand)
The difference between this anion dimer and two anions satisfying Formula II is that in the dimer the metal atom occupies two bridging coordinations, reducing the number of ligands required from 12 to 10. Is. In oligomeric complexes containing up to 5 metal atoms, the following general formula can be written to describe the anion: (IV) M _m L _{6 + 4 (m-1) where} M and L are Already defined, m
Is 2 to 5) When the number of Group 8 5/6 metal atoms reaches 6, an occupied pair of bridging ligands that bond to six Group 8 5/6 metal atoms and adjacent metal atoms A ring structure consisting of and becomes possible. Although rings with more Group 8 5/6 metal atoms are possible, most high molecular weight oligomers contain rings containing six Group 8 5/6 metal atoms (usually a pair of adjacent rings). It has a pair of metal atoms in one ring that is occupied by metal atoms). The following formulas are typical of oligomeric anions containing 6, 8 or 10 Group 8 5/6 metal atoms satisfying the requirements of the invention: (V) M ₆ L ₂₄ (VI) M ₈ L ₃₂ (VII) M ₁₀ L ₃₈ , where M and L are as previously defined 6,
Other oligomeric forms containing 8 or 10 Group 8 5/6 metal atoms are of course possible.

The net negative charge of the above anion is not shown, which is a Group 8 5/6 metal and a ligand (Group 8 5/6).
This is because it depends on the selection of a more electronegative ligand) which tends to shift the metal to another Group 8 5/6 metal exhibiting a higher oxidation state and a different oxidation state selection. For iridium and halide ligands, the net negative charge of the anion of formula II is -2, -4 for formula III, -6 for formula V, and -8 for formulas VI and VII. For anionic hexacoordination complexes with a negative charge in the range -2 to -8, all described as effective,
The net negative charge magnitude, if any, has little effect on the desired lattice configuration.

The important point to observe is that all molecular weight and sterically varying oligomers contemplated for the practice of this invention are group 8 5/6 metal atoms and face centered cubic of the photosensitive silver halide grains. To show an alternating pattern with ligands similar to those found in the crystal lattice structure. Therefore, adjacent 8
Since the group 5/6 metal atoms are oriented so as to occupy adjacent cation positions in the crystal lattice structure, the oligomer is characterized by
It can be provided in the plane of the crystal lattice structure. It is also possible to use tetra-coordination complexes instead of hexa-coordination complexes to achieve adjacent incorporation of Group 8 metal atoms. The bridging ligand is capable of forming a covalent bond with two adjacent Group 8 group 5/6 metal ions. In its simplest form,
The ligand can be a halide such as a fluoride, chloride, bromide and iodide atom. Due to the size compatible with the face centered cubic crystal lattice structure of the silver halide grains, the ligand is preferably a chloride or bromide ligand. In addition to halide ions, it is also possible to select other bridging ligands. For example, a limited range of aquo (HOH) ligands can be replaced with halide ligands. Pseudohalogen ligands such as cyanide (CN), cyanate (OCN), thiocyanate (SCN), selenocyanate (SeCN), and tellurocyanate are contemplated. In addition, nitrosyl (NO), thionitrosyl (NS), azide (N
Other ligands are possible, such as ₃ ), oxo (O), and carbonyl (CO). The choice of ligand other than halide and aquo ligands must be such that the ligand promises to effect photographic performance in its own right. If the ligand is the same as the grain-structured halide, the improving effect is entirely attributable to the incorporated Group 8 5/6 metal ion. Similarly,
Aquo ligands have not been reported to produce improved effects.

A pair of anionic hexacoordination complexes having one or more charges satisfying the cation (satisfying R in formula I, described above) are used as convenient conventional hexacoordination complexes. Either technique (above, Smith and T
It can be incorporated as a particular solid or solution at any stage of emulsion preparation using (as taught by rivelli) (which is hereby incorporated by reference). The presence of a hexacoordination complex during grain formation is preferred to ensure incorporation of Group 8 5/6 metal into the crystal structure. It is believed that the complex is present prior to or during silver halide precipitation. Also, 8 group 5
The / 6 metal can be effectively incorporated by the presence of the complex (ie the complex and one or more ripening agents are present simultaneously in the emulsion) during surface ripening of the grains. The concentration of Group 8 5/6 metal incorporated into the particles is too low to have a significant effect on the shape or placement of the particles produced.

Obtaining an emulsion satisfying the requirements of the invention was achieved by discovering a new precipitation method. In this method, grain nucleation occurs in a high chloride environment where iodide ions are present under conditions that favor the appearance of {100} crystal faces. Grain formation results in the inclusion of iodide in the cubic lattice formed by silver ions, and because of the larger diameter of iodide ions compared to chloride ions, the remaining chloride ions collapse. . The incorporated iodide ions introduce crystal irregularities which, in further grain growth, give rise to tabular grains rather than regular (cubic) grains.

Incorporation of iodide ions into the crystal structure at the beginning of nucleation results in one or more cubic planes,
It is believed to produce cubic grain nuclei that are formed with growth that promotes one or more crystal lattice irregularities. A cubic plane containing at least one crystal lattice disorder, then
It accepts silver halide in a promoted proportion as compared to the regular cubic crystal plane (ie lacking the crystal lattice disorder). If only one of the cubic faces has a crystal lattice disorder, grain growth on only one face is promoted and the grain structure resulting from continued growth is the rod. The same result occurs when only two opposing parallel faces of the cubic structure have growth promoting disorder. But,
If either of two adjacent cubic faces has a crystal lattice disorder, continued growth promotes growth of both faces and produces a tabular grain structure. It is believed that the tabular grains of the emulsions of this invention are formed by these grain nuclei having 2, 3 or 4 faces with growth promoting crystal lattice disorder.

At the beginning of precipitation, the reaction vessel is provided with a dispersion medium and conventional silver and associated electrodes for monitoring halide ion concentration in the dispersion medium. A halide ion that is at least 50 mol% chloride is introduced into the dispersion medium (ie, at least half of the halide ions in the dispersion medium are chloride ions). The pCl of the dispersion medium is adjusted to facilitate the production of {100} grain faces during nucleation. That is, within the range of 0.5-3.5, preferably 1.0-3.0, and optimally 1.5-
It is within the range of 2.5.

The grain nucleation process begins when the silver jet is opened to introduce silver ions into the dispersion medium. Preferably the iodide ions are simultaneously together or,
Optimally, it is introduced into the dispersion medium before opening the silver jet. Effective tabular grain formation can occur over a range of iodide ion concentrations up to the saturation limit of iodide in silver chloride. The saturation limit of iodide in silver chloride is H.I.
Hirsch's "Photographic Emulsion Grains with C"
ores: Part I Evidence for the Presence of Cores ",
J. of Photog. Science, vol. 10 (1962), pages 129-134, it is reported to be 13 mol%. For silver halide grains in which equimolar proportions of chloride and bromide are present, up to 27 mole percent iodide, based on silver, can be incorporated into the grain. In order to avoid precipitation of a separate silver iodide phase, it is preferable to perform grain nucleation and grain growth below the iodide saturation limit, thereby avoiding the formation of additional undesirable categories of grains. It is generally preferred to keep the iodide ion concentration in the dispersion medium below 10 mol% at the beginning of nucleation. In fact
With nucleation, only small amounts of iodide are needed to achieve the desired tabular grain population. At least 0.00
Initial iodide ion concentrations up to 1 mol% are contemplated.
However, for convenience of reproducibility of results, an initial iodide concentration of at least 0.01 mol% is preferred, and optimally at least 0.05 mol%.

In the preferred method, silver iodochloride grain nuclei are formed during the nucleation step. A small amount of bromide ion can be present in the dispersion medium during nucleation. Any amount of bromide ion compatible with at least 50 mole% halide in the grain nuclei in which chloride ion is present can be present in the dispersing medium during nucleation. The grain nuclei preferably comprise at least 70 mol% and optimally at least 90 mol% chloride ions, based on silver.

Grain nucleation occurs immediately upon introduction of silver ions into the dispersing medium. For operational convenience and reproducibility, silver ion introduction during the nucleation step is preferably
It is extended for a convenient period, typically 5 seconds to less than 1 minute. It is not necessary to add additional chloride ions to the dispersion medium during the nucleation step as long as the pCl remains within the above range. However, it is preferred to introduce both the silver salt and the halide salt simultaneously during the nucleation step. The advantage of adding the halide salt along with the silver salt throughout the nucleation process ensures that the grain nuclei formed after the initial silver ion addition have essentially the same chloride content as the grain nuclei initially formed. That is what you can do. Addition of iodide ions during the nucleation step is particularly preferred. The iodide ion deposition rate far exceeds that of other halides, so iodide is consumed in the dispersion medium unless replenished.

Any convenient conventional source of silver and chloride ions can be used during the nucleation step. The silver ion is preferably an aqueous silver ion solution (for example,
(A silver nitrate solution). Chloride ions are preferably introduced as alkali or alkaline earth chlorides (eg lithium, sodium and / or potassium chloride bromide and / or iodide).

It is possible, but not preferred, to introduce silver chloride or silver iodochloride Lippmann grains into the dispersing medium during the nucleation step. In this case, grain nucleation has already occurred, and the nucleation step already referred to in this specification is actually a step for introducing crystal lattice disorder in the grain plane. The advantage of delaying the grain face crystal lattice disorder introduction process is that it produces thicker tabular grains than would otherwise be obtained.

The dispersion medium contained in the reaction vessel prior to the nucleation step comprises water, the dissolved halide ions previously discussed, and the peptizer. The dispersion medium can exhibit a pH within the usual range that is convenient for silver halide precipitation, typically 2-8. It is preferred, but not necessary, to maintain the dispersion medium on the neutral acid side (ie, below pH 7.0). The preferred pH range for precipitation is 2. to minimize fog.
It is 0 to 5.0. Using a mineral acid such as nitric acid or hydrochloric acid, and a base such as alkali hydroxide,
H can be adjusted. It is also possible to incorporate a pH buffer.

The peptizer is a silver halide emulsion for photography,
In particular, any convenient conventional form known to be useful for precipitating tabular grain silver halide emulsions can be employed. See Research Discl for an overview of peptizers.
osure, Vol. 308, December 1989, Section IX. Research Disclosure is Kenneth Maso
n Publication Ltd., Emsworth, Hampshire PO10 7DQ,
Published by England. Maska already quoted
Synthetic polymeric peptizers of the type disclosed by sky I (which are hereby incorporated by reference) can be used, while gelatinous peptizers (eg, gelatin and gelatin derivatives) can be used. It is preferably used. The use of deionized gelatinous peptizers is a well-known practice, as gelatinous peptizers produced and used in the field of photography typically contain significant concentrations of calcium ions. In the latter case, the removed calcium ions are supplemented by the addition of divalent or trivalent metal ions such as alkaline earth or alkaline earth metals (preferably magnesium, calcium, barium or aluminum ions). It is preferable. Particularly preferred peptizers are low methionine gelatinous peptizers (ie containing less than 30 micromoles of methionine per gram of peptizer), optimally less than 12 micromoles per gram of peptizer. belongs to. These peptizers and their preparation are disclosed in the previously cited patent specifications of Maskasky II and King et al. (Herein incorporated by reference). But Maskasky I and Maskasky II
It should be noted that grain growth modifiers of the type taught for inclusion in emulsions (e.g., adenine) are not suitable for inclusion in dispersion media. This is because these grain growth modifiers promote twinning and formation of tabular grains having {111} major faces. Generally, at least about 10% and typically 20% of the dispersion medium that produces the finished emulsion.
~ 80% is present in the reaction vessel at the beginning of the nucleation step. It is common practice to maintain a relatively low level of peptizer, typically 10-20% of the finished emulsion, in the reaction vessel at the beginning of precipitation. In order to increase the proportion of thin tabular grains with {100} faces that are formed during nucleation, at the beginning of the nucleation step, the concentration of the peptizing agent in the dispersion medium is 0. It is preferably in the range of 5 to 6% by weight. It is common practice to add gelatin, gelatin derivatives and other vehicles as well as vehicle extenders to prepare emulsions for post-precipitation coating. Natural levels of methionine can be present in the added gelatin and gelatin derivatives after the precipitation is complete.

The nucleation step can be carried out at any convenient conventional temperature for precipitation of silver halide emulsions. Temperatures near room temperature (eg, 30 ° C to about 9 ° C)
0 ° C) is considered, and the nucleation temperature is from 35 ° C to
Temperatures in the range of 70 ° C are preferred. Since grain nucleation occurs almost instantaneously, only a small fraction of the total silver introduced into the reaction vessel is needed during the nucleation process. Typically, about 0.1-10 mol% of the total silver is introduced during the nucleation process.

The nucleation step is followed by a grain growth step in which grain nuclei grow until tabular grains having {100} major faces of the desired average ECD are obtained. The purpose of the nucleation step is to form a population of particles with the desired incorporated crystallographic disorder, whereas the purpose of the growth step is to avoid or minimize the formation of additional particles. , Depositing (growing) additional silver halide to existing grain populations. If additional grains are formed during the growth step, the polydispersity of the emulsion is increased and if the conditions in the reaction vessel are not maintained as described above during the nucleation step, the additional grains formed during the growth step are formed. Of the above-mentioned grain populations will not have the desired tabular grain characteristics described above.

In its simplest form, the emulsion preparation process according to the invention can be carried out as a single jet precipitation from start to finish without interruption of the introduction of silver ions. As is generally recognized by those skilled in the art, the spontaneous transition from particle formation to particle growth is
It also occurs at a uniform rate of silver ion introduction. This is because the size of the grain nuclei increases until they reach the point of accepting silver and halide ions at a rate that is fast enough that new grains cannot form, so that the grain nuclei are removed from the dispersion medium by silver and halogen. This is because it increases the rate at which the compound ions can be accepted. Although easy to operate, single jet precipitation limits halide content and profile and generally results in a more polydisperse grain population.

Since a higher percentage of the particle population can be optimally sensitized or optimally prepared for photographic use,
It is usually preferred to prepare photographic emulsions with the most geometrically uniform grain populations achievable. Furthermore, it is usually more convenient to formulate a relatively monodisperse emulsion to obtain the desired sensitometric profile than to precipitate a single polydisperse emulsion that matches the desired profile.

In the preparation of emulsions according to the present invention it is possible to interrupt the introduction of silver and halide salts at the end of the nucleation step and before beginning the growth step which brings the desired final size and shape to the emulsion. preferable. The emulsion is held within the temperature range described herein for nucleation for a period sufficient to reduce grain dispersity. Retention times can range from 1 minute to several hours, with typical retention times ranging from 5 minutes to 1 hour. During the retention period, the relatively smaller particles age Ostwald over the remaining relatively larger particle nuclei, with the overall result that the particle dispersity is reduced.

If desired, during the holding period the ripening rate can be increased by the presence of ripening agents in the emulsion. The usual simple way to accelerate ripening is to increase the halide ion concentration of the dispersion medium. This creates a silver ion complex with multiple halide ions that promote ripening. When using this method, it is preferable to increase the chloride ion in the dispersion medium. That is, it is preferable to lower the pCl of the dispersion medium within the range in which the increased dissolution of silver halide is observed. Alternatively, ripening can be accelerated and the proportion of projected area of the grain population occupied by {100} tabular grains can be increased by using conventional ripening agents. Preferred ripening agents are sulfur-containing ripening agents such as thioethers and thiocyanates. Typical thiocyanate ripening agents are described in Nietz et al., US Pat. No. 2,222,264.
No. 2,448,53 to Lowe et al.
No. 4, and Illingsworth, U.S. Pat. No. 3,320,069 (hereby incorporated by reference). Typical thioether ripening agents are McBride, U.S. Pat. No. 3,271,157, Jones, U.S. Pat. No. 3,574,628 and Rosencra.
ntz et al., U.S. Pat. No. 3,737,313, which is hereby incorporated by reference. Recently crown thioethers have been proposed for use as ripening agents. Aging agents with primary or secondary amino components such as imidazole, glycine or substituted derivatives are also effective. Sodium sulfite has also been demonstrated to be effective in increasing the percentage of total grain projected area occupied by {100} tabular grains.

Once the desired population of grain nuclei has been formed, the emulsions of this invention are prepared according to any convenient conventional precipitation technique which precipitates silver halide grains bounded by {100} grain faces. Grain growth to obtain begins. It is necessary that the iodide and chloride ions be incorporated into the grains during nucleation, so that the iodide and chloride ions are present in the finished grains substantially at the nucleation sites, but the cubic crystal Halides or combinations of halides known to form a lattice structure can be used during the growth process. Irregular grain nuclei that cause tabular grain growth once introduced persist during the next grain growth regardless of halide precipitation, so iodide and chloride ions are incorporated into the grains during the growth process. It is not necessary that the given halide or combination of halides form a cubic lattice. This means that 13 mol% of the precipitated silver iodochloride (preferably 6 mol%)
Mol%), iodide levels above 40 mol% (preferably 30 mol%) of the precipitated silver iodobromide, and precipitated silver iodohalide containing bromide and chloride. Exclude only intermediate levels of iodide. When silver bromide or silver iodobromide is attached during the growth step, it is in the range of 1.0 to 4.2, preferably 1.6 to 4.2.
It is preferable to maintain pBr in the dispersion medium in the range of 3.4. When silver chloride, silver iodochloride, silver bromochloride or silver iodobromochloride is deposited during the growth step, it is preferred to maintain pCl in the dispersion medium within the ranges already mentioned in the nucleation step described.

It was quite an unexpected finding that a reduction in tabular grain thickness of up to 20% could be achieved by introducing specific halides during grain growth. Surprisingly, addition of bromide in the range of 0.05 to 15 mol%, preferably 1 to 10 mol%, based on silver during grain growth is more than achieved under the same conditions precipitation without bromide ions. Is relatively thinner {1
00} was observed to produce tabular grains. Similarly, addition of iodide in the range of 0.001 to less than 1 mol% based on silver during grain growth is relatively thinner than that achieved for precipitation under the same conditions without iodide ions. It was observed to produce {100} tabular grains.

Both silver and halide salts are preferably introduced into the dispersing medium during the growth process. In other words, double jet precipitation is contemplated, with the addition of iodide salt introduced with the remaining halide salt or through a separate jet if necessary. The rates of introducing silver and halide salts are controlled to avoid re-nucleation (ie formation of new grain populations). The addition rate control to avoid re-nucleation is Wilgus
German Patent Publication No. 2,107,118, Ir
IE, U.S. Pat. No. 3,650,757, Kur.
U.S. Pat. No. 3,672,900 to Z. Sait
o U.S. Pat. No. 4,242,445, Teit
European patent application 80102242 to Schied et al. and Wey's "Growth Mechanism of AgBr Crys".
tals in Gelatin Solution ", Photographic Science an
d Engineering, Vol. 21, No. 1, January 1977,
It is generally well known in the art, as described on page 14.

In the simplest form of the invention, the nucleation and growth stages of particle precipitation occur in the same reaction vessel.
However, it is recognized that grain precipitation can be interrupted, especially after the end of the nucleation step. Furthermore, two separate reaction vessels can be replaced by the single reaction vessel described above. The nucleation step of particle precipitation can be carried out in an upstream reaction vessel (referred to herein as a nucleation reaction vessel) and the dispersed particle nuclei are transferred to a downstream reaction vessel (wherein the growth step of particle precipitation occurs). Call the growth reaction vessel). US Pat. No. 3,79 to Pose et al.
0,386, Forster et al., U.S. Pat. No. 3,897,935, Finnicum et al., U.S. Pat. No. 4,147,551, and Verh.
One arrangement of this type uses a closed nucleation vessel, as described in U.S. Pat. No. 4,171,224 to Ille et al., which is hereby incorporated by reference. , Can receive the reactant upstream of the growth reaction vessel and agitate. In these arrangements, the contents of the growth reaction vessel are recycled to the nucleation reaction vessel. p
It is contemplated herein that various important parameters controlling particle formation and growth, such as H, pAg, aging, temperature, and residence time, are independently controlled in separate nucleation and growth reaction vessels. To be In order to make the grain nucleation completely independent of the grain growth occurring in the growth reaction vessel downflow of the nucleation reaction vessel, it is better not to recycle the contents of the growth reaction vessel to the nucleation reaction vessel at all. A preferred arrangement for separating particle nucleation from the contents of a growth reaction vessel is Mignot US Pat. No. 4,334,334.
012 (which also discloses useful aspects of ultrafiltration during particle growth), Urabe, US Pat.
No. 879,208, and published European patent applications Nos. 326852, 326852 and 35553.
5 and 370116, Ichizo, published European Patent Application No. 368275, Ur.
Published European Patent Application No. 374954 of Abe et al. and Japanese Patent Application Laid-Open No. 2-172817 (19) of Onishi et al.
90).

The method of grain nucleation has been described herein above using the term iodide to form the crystalline disorder necessary for tabular grain formation, but in the following examples: As described, another nucleation method was devised that eliminated the need for iodide ions present during nucleation to produce tabular grains. Moreover, these alternative methods are compatible with the use of iodide during nucleation. Therefore, these methods are quite reliable during nucleation for tabular grain formation,
Alternatively, it can be relied upon in combination with iodide ions during nucleation to produce tabular grains.

Rapid grain nucleation, so-called dump nucleation, where a significant level of the dispersion medium is supersaturated with the halides and silver ions present during nucleation, is the cause of tabular grain irregularity. Promote the introduction of. Nucleation is accomplished essentially instantaneously, so that immediate supersaturation to the preferred pCl range described herein is entirely consistent with this method.

It was also observed that maintaining a level of peptizer in the dispersing medium during grain nucleation at levels of less than 1% by weight enhances tabular grain formation. It is believed that the fusion of grain nucleus pairs is at least partly responsible for introducing the crystal disorder that induces tabular grain formation. Limited coalescence can be facilitated by the use of no peptizer in the dispersion medium or by initially limiting the concentration of peptizer. Mignot
U.S. Pat. No. 4,334,012 describes peptizer-free particle nucleation with removal of soluble salt reaction products to avoid nuclear fusion. Since limited fusion of particle nuclei may be desirable, Mignot's active intervention to eliminate particle nuclei fusion can either be eliminated or moderated. It is also envisaged to enhance the limited particle fusion by using one or more peptizers which have low adsorption to the particle surface.
For example, it is noted that low methionine gelatin of the type disclosed by Maskasky II is not absorbed as well as gelatin containing higher levels of methionine. Furthermore, moderate particle adsorption can be achieved with so-called "synthetic peptizers" (ie peptizers made from synthetic polymers).
The maximum amount of peptizer compatible with limited particle core fusion is, of course, related to the strength of adsorption to the particle surface. Once grain nucleation is complete, shortly after the introduction of the silver salt, the peptizer level can be increased to a convenient conventional level for the rest of the precipitation process.

The emulsions of the present invention can include silver iodochloride emulsions, silver iodobromochloride emulsions and silver iodochlorobromide emulsions.
At concentrations of up to 10 ^-2 moles per mole of silver, typically less than 10 ^-4 moles per mole of silver, conventional grain dopants (other than Group 8 metal dopants) are present in the grains. Can exist For example, copper, thallium, lead,
Metal compounds such as mercury, bismuth, zinc, cadmium, rhenium can be present during particle precipitation, preferably during the growth stage of precipitation. Conventional grain dopant selection is described in Research Disclosure, Vol. 308, December 19189, Item 308119, Section I, Subsection D.

Conventional high chloride tabular grain emulsions having tabular grains separated by {111} are inherently unstable and a morphological stabilizer to prevent the grains from reverting to their nontabular morphology. The present invention is advantageous in providing high chloride (higher than 50 mole% chloride) tabular grain emulsions because of the presence of Highly preferred, high chloride emulsions are higher than 70 mol% according to the invention (optimally 90%).
Higher than mol%) chloride.

Although not essential to the practice of the present invention, {10
An additional treatment that can be used to maximize the population of tabular grains having 0} major faces is to incorporate agents that can suppress the appearance of non- {100} grain crystal faces of the emulsion during emulsion preparation. is there. If an inhibitor is used, it can be activated during grain formation, growth or throughout precipitation.

Useful inhibitors, under the contemplated conditions of precipitation, are organic compounds containing nitrogen atoms with resonance-stabilized p electron pairs. Resonance stabilization prevents protonation of the nitrogen atom under the relative acid conditions of precipitation. Aromatic resonance can rely on the stability of the π electron pair of the nitrogen atom. The nitrogen atom can be incorporated into the aromatic ring, such as an azole or azine ring, or can be a ring substituent on the aromatic ring.

In one preferred form, the inhibitor may satisfy the following formula (I): (I)

[0073]

[Chemical 1]

(Wherein Z represents an atom necessary to complete a 5- or 6-membered aromatic ring structure and is preferably formed by carbon and nitrogen ring atoms).
Aromatic rings are those with 1, 2 or 3 nitrogen atoms. Particularly contemplated ring structures are 2H-pyrrole, pyrrole, imidazole, pyrazole, 1,2,3-triazole, 1,2,4-triazole, 1,3,5-triazole, pyridine, pyrazine, pyrimidine, and pyridazine. Include.

When the stabilized nitrogen atom is a ring substituent, preferred compounds satisfy formula (II): (II)

[0076]

[Chemical 2]

Wherein Ar is an aromatic ring structure having 5 to 14 carbon atoms, and R ¹ and R ² are each independently hydrogen, Ar or a convenient aliphatic group, or , Together to complete a 5- or 6-member ring.)
Ar is preferably a cyclic carboaromatic ring such as phenyl or naphthyl. Alternatively, any nitrogen and carbon bearing the above aromatic ring can be attached to the nitrogen atom of formula II via a ring carbon atom. In this case, the resulting compound satisfies both formula I and II. Any of a wide variety of aliphatic groups can be selected. The most easily considered aliphatic groups are alkyl groups, preferably 1 to
It has 10 carbon atoms, most preferably 1 to 6 carbon atoms. Functional substituents on any of the alkyl groups known to be compatible with silver halide precipitation can be present. It is also conceivable to use cycloaliphatic substituents exhibiting a 5- or 6-membered ring such as cycloalkanes, cycloalkenes and aliphatic heterocycles such as those having oxygen and / or nitrogen heteroatoms. Cyclopentyl, cyclohexyl, pyrrolidinyl, piperidinyl, furanyl and similar heterocycles are especially contemplated.

The following are Formula I and / or Formula I
Representative compounds believed to satisfy I:

[0079]

[Chemical 3]

[0080]

[Chemical 4]

[0081]

[Chemical 5]

[0082]

[Chemical 6]

[0083]

[Chemical 7]

[0084]

[Chemical 8]

[0085]

[Chemical 9]

The selection of preferred inhibitors and their effective concentrations can be carried out by the following selection procedure: The compounds considered for use as inhibitors are selected from essentially cubic grains with a mean grain edge length of 0.3 μm. It is added to the silver chloride emulsion. This emulsion is 0.2 in sodium acetate.
Molar, pCl is 2.1, a pH that is at least 1 unit greater than the pKa of the compound considered. The emulsion is held with the inhibitor for 24 hours at 75 ° C. Two
When the cubic grains have a square edge of {100} crystal faces than the control, which differs only in the absence of a possible compound, after 4 hours of microscopic examination, the incorporated compound acts as an inhibitor. There is. The angular crossing edge of the {100} crystal plane is the fact that the particle edge is the most active site on the particle due to the ions re-entering the dispersion medium. By maintaining sharp edges, the suppressor acts, for example, at rounded edges and corners to suppress the appearance of non- {100} grain crystal faces. In some cases, replacing the dissolved silver chloride that adheres exclusively on the edges of the cubic grains, {1
A new particle population is formed, which is bounded by the {00} crystal planes. Optimal inhibitor activity occurs when the new grain population is a tabular grain population in which the tabular grains are bounded by {100} major crystal faces.

It is particularly conceivable to epitaxially deposit the silver salt in the form of tabular grains which serve as a host. Conventional, epitaxial deposition on high chloride silver halide grains is described by Maskasky, US Pat. No. 4,435,50.
No. 11, especially Example 24B, U.S. Pat. Nos. 4,786,588 and 4,791,05 to Ogawa.
3, Hasebe et al., U.S. Pat. No. 4,820,
624 and 4,865,962, Sugi.
"Mechanism of Halide Co" by moto and Miyake
nversion Process of Colloidal AgCl Microcrystals b
y Br ^- Ions ", Parts I and II, Journal of Colloid a
nd Interface Science, Vol. 140, No. 2, 1990 12
Moon, pp. 335-361, Houle et al., US Pat.
5,992, Japanese Patent Application Laid-Open No. 03-252649 (prior application Japanese Patent Application No. 02-051165 filed on Mar. 2, 1990) and Japanese Patent Application Laid-Open No. 03-288143 (April 4, 1990). (Japanese Patent Application No. 02-089380 is a priority). The disclosures of the above US patent specifications are incorporated herein by reference.

The emulsion used in the present invention was treated with activated gelatin (The Theory of the Photograph by TH James).
ic Process 4th Edition, Macmillan, 1977, pp. 76-76) or sulfur, selenium, tellurium, gold,
Research Disclosur with platinum, palladium, iridium, osmium, rhenium or phosphorus sensitizers, or combinations of these sensitizers, for example at pAg levels of 5-10, pH levels of 5-8 and temperatures of 30-80 ° C.
e, Vol. 120, April 1974, Item 12008, Research
Disclosure, Vol. 134, June 1975, Item 13452
U.S. Pat. No. 1,623,49 to Sheppard et al.
No. 9, Matthies et al., US Pat. No. 1,67
3,522, Waller et al., U.S. Pat.
399,083, Damschroder et al., U.S. Pat. No. 2,642,361, McVeig.
U.S. Pat. No. 3,297,447 to Dun, Dunn.
U.S. Pat. No. 3,297,446 to McBri.
deno British Patent No. 1,315,755, Be
rry et al., U.S. Pat. No. 3,772,031, G
Ilman et al., U.S. Pat. No. 3,761,267, Ohi et al., U.S. Pat. No. 3,857,711, Klinger et al. U.S. Pat. No. 3,565,633.
No. 3,901, of Oftedahl
714 and Simons British Patent No. 1,
Chemical sensitization as described by US Pat.
thiocyanate derivatives as described by Hroder in U.S. Pat. No. 2,642,361, Lowe et al. in U.S. Pat. No. 2,521,926, Williams.
U.S. Pat. No. 3,021,215 and Bi
thioether compounds described in gelow, U.S. Pat. No. 4,054,457, as well as Doses, U.S. Pat. No. 3,411,914, Kuwaba.
Ra et al., U.S. Pat. No. 3,554,757, Og.
Uchi et al U.S. Pat. No. 3,565,631 and Oftedahl U.S. Pat. No. 3,901,714.
Azaindene, azapyridazine,
As well as published European patent application No. 294149, such as azapyrimidine, Miyashi et al. And published European patent application No. 297804, such as Tanaka, and published European patent application No., such as Nishikawa. It is carried out in the presence of thiosulfonate as described in 293917. Additionally or alternatively, the emulsions can be treated with a low pAg using, for example, the hydrogen described in Janusonis US Pat. No. 3,891,446 and Babcock et al. US Pat. No. 3,984,249. (Eg lower than 5), high p
H (eg, higher than 8) treatment, or A
Llen et al., U.S. Pat. No. 2,983,609.
Research Disclosure, Vol. 136, of Oftedahl, etc.
August 1975, Item 13654, Lowe et al., U.S. Pat. Nos. 2,518,698 and 2,739,060, Roberts et al., U.S. Pat. No. 2,743,1.
82 and 2,743,183, Cham.
Bers et al U.S. Pat. No. 3,026,203 and Bigelow et al U.S. Pat. No. 3,361,564.
Reduction sensitization can be carried out using reducing agents such as stannous chloride, thiourea dioxide, polyamines and amineboranes as described in US Pat.

Chemical sensitization is described by Philipperts et al., US Pat. No. 3,628,960, Kofro.
N. et al., U.S. Pat. No. 4,439,520, Dic
Kerson U.S. Pat. No. 4,520,098, Maskasky U.S. Pat. No. 4,435,501.
U.S. Pat. No. 4,693,96 to Ihama et al.
No. 5, and Ogawa US Pat. No. 4,791,
It can be carried out in the presence of a spectral sensitizing dye as described in 053. Chemical sensitization was performed on silver halide grains as described in British Patent Application Publication No. 2,038,792 to Haugh et al. And Published European Patent Application No. 302528 to Mifrne et al. Can be directed to the site or the crystal plane. Mor
Ugan U.S. Pat. No. 3,917,485, B
Ecker, U.S. Pat. No. 3,966,476 and Research Disclosure, Vol. 181, May 1979, Item 18155, where the photosensitized centers derived from chemical sensitization are twin-jet added or silver. And partially or wholly plugged by precipitation of an additional layer of silver halide using such means as pAg circulation with separate addition of halide salts. Also, the above M
a chemical sensitizer, as described by Organ,
It can be added before or simultaneously with the additional silver halide formation. Chemical sensitization can be carried out during or after halide conversion, as described in published European patent application No. 273404 to Hasebe et al. Often, epitaxial deposition on selected tabular grain sites (eg, edges or corners) is
It can be used either for direct chemical sensitization or for itself to perform the action normally performed by chemical sensitization.

The emulsion of the present invention can be prepared by using cyanine compounds, merocyanine compounds, cyanine compounds and merocyanine compound complexes (for example, tri-, tetra- and polynuclear cyanine compounds and merocyanine compounds), styryl compounds, merostyryl compounds, streptocyanin compounds, It can be spectrally sensitized with dyes from various classes, including polymethine dye classes, including hemicyanines, arylidenes, allopolar cyanines, and enamine cyanines.

Cyanine spectral sensitizing dyes are two types of basic heterocyclic nuclei connected by a methine bond, such as quinolinium, pyridinium, isoquinolinium,
3H-indolium, benzoindolium, oxazolium, thiazolium, selenazolium, imidazolium, benzoxazolium, benzothiazolium, benzoselenazolium, benzoterrazolium, benzimidazolium, naphthoxazolium, naphthothiazol Included are those derived from ium, naphthoselenazolium, naphthotelrazolium, thiazolinium, dihydronaphthothiazolium, pyrylium, and imidazopyrazinium quaternary salts.

The merocyanine spectral sensitizing dyes are cyanine dye-type basic heterocyclic nuclei and acidic nuclei connected by methine bonds, such as barbituric acid, 2-thiobarbituric acid, rhodanin, hydantoin, 2- Thiohydantoin, 4-thiohydantoin, 2-pyrazolin-5-one, 2-isoxazoline-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, malonnitrile, malonamide, isoquinoline-4
-On, chroman-2,4-dione, 5H-furan-2
-One, 5H-3-pyrrolin-2-one, 1,1,3-
Those derived from tricyanopropene and telluracyclohexanedione.

It is possible to use one or more spectral sensitizing dyes. Dyes with maximum sensitization at wavelengths across the visible and infrared spectra, and dyes with a wide variety of spectral sensitivity curve shapes are known. The choice and relative proportion of dyes depends on the region of the spectrum of sensitivity desired and on the shape of the spectral sensitization curve desired. Dyes with overlapping spectral sensitivity curves often produce a combined curve where the sensitivity at each wavelength in the overlap region is approximately equal to the sum of the sensitivities of the individual dyes. Therefore, it is possible to use a combination of dyes with different maxima to achieve a spectral sensitivity curve with a maximum midway between the sensitization maxima of the individual dyes.

Supersensitization (that is, spectral sensitization in a certain spectral region is greater than sensitization derived from any concentration of a single dye among a plurality of dyes or from an addition effect of a plurality of dyes. A combination of spectral sensitizing dyes that give rise to) can be used. Supersensitization, selected combinations of spectral sensitizing dyes and other additives (eg stabilizers and antifoggants, development accelerators or inhibitors, coating aids, optical brighteners and antistatic agents). Can be achieved with. Any one of several mechanisms, as well as compounds that ensure supersensitization, can be found in Gilma.
n's Photographic Science and Engineering, Vol. 18,
1974, pp. 418-430.

Spectral sensitizing dyes can also act on the emulsion in other ways. For example, spectral sensitizing dyes can increase photographic sensitivity in the spectral region where they are inherently sensitive. US Pat. No. 2,13 to Brooker et al.
1,038, Illingsworth et al., U.S. Pat. No. 3,501,310, Webster.
U.S. Pat. No. 3,630,749, Spen, et al.
The spectral sensitizing dyes may also be antifoggants or stabilizers, as disclosed in US Pat. No. 3,718,470 to Ce et al. and US Pat. No. 3,930,860 to Shiba et al. It can also act as a development accelerator or inhibitor, a reducing or nucleating agent, and a halogen or electron acceptor.

In particular, useful spectral sensitizing dyes for sensitizing the emulsions described herein are British Patent 742,112, Brooker US Pat. No. 1,846,300.
Issue No. 1,846,301 Issue No. 1,846,302
Issue 1, 846, 303 Issue 1, 846, 304
No. 2,078,233 and 2,089,72
No. 9, Brooker et al., US Pat. No. 2,16
5,338, 2,213,238, 2,49
3,747, 2,493,748, 2,52
No. 6,632, No. 2,739,964, (Reissue Patent No. 24,392), No. 2,778,823, No. 2,
917,516, 3,352,857, 3,4
11,916 and 3,5311,111, Sprague U.S. Pat. No. 2,503,776, Nys et al. U.S. Pat. No. 3,282,933, Riester U.S. Pat. , 660, 102
, Kampfer et al., U.S. Pat. No. 3,660,
103, Taber et al., U.S. Pat. No. 3,33.
5,010, 3,352,680 and 3,3
84,486, Lincoln et al U.S. Pat. No. 3,397,981, Fumia et al U.S. Pat. Nos. 3,482,978 and 3,623,881, Spence U.S. Pat. Third 3,718,47
No. 0 and Mee US Pat. No. 4,025,34
No. 9 (which is hereby incorporated by reference). Examples of useful supersensitizing dye combinations, non-light absorbing additives that act as supersensitizers or useful dye combinations are described in McFall et al., US Pat. No. 2,937,089, Motter US Pat. See US Pat. No. 3,506,443, and US Pat. No. 3,672,898 to Schwan et al., Which is hereby incorporated by reference.

Spectral sensitizing dyes can be added at any stage during emulsion preparation. Wall's Phot
ographic Emulsions, American Photographic Publishi
ng Co., Boston, 1929, p. 65, Hill U.S. Pat. No. 2,735,766, Philippaert.
U.S. Pat. No. 3,628,960, Loc, et al.
Ker et al., U.S. Pat. No. 4,225,666 and Research Disclosure, Vol. 181, May 1979, Item 18155, and Tani et al., Published European Patent Application No. 301508. , They can be added at the beginning of precipitation or during precipitation. U.S. Pat. No. 4,439,520 to Kofron et al., U.S. Pat. No. 4,520 to Dickerson,
098, Maskasky U.S. Pat. No. 4,4.
35,501 and Philippaerts
They can be added before or during chemical sensitization, as described in the above cited references. Published European patent application No. 2871 of Asami et al.
They can be added before or during emulsion washing, as described in published patent application No. 00 and published European patent application 291399 to Metoki et al. Collins et al., U.S. Pat.
The dye can be mixed directly prior to coating, as described in US Pat. A small amount of iodide can be adsorbed on the emulsion grains to promote aggregation and adsorption of the spectral sensitizing dye, as described in the above-referenced Dickerson. Post-processing dye stain can be reduced by the proximity of the high iodide grains to the dyed emulsion layer, as described by Dickerson. According to their solubility, the spectral sensitizing dyes, as a solution of water or a solvent such as methanol, ethanol, acetone or pyridine, are described in US Pat. No. 3,822,135 to Sakai et al. Dissolved in an agent solution, or in US Pat. No. 3,469,987 to Owens et al.
It can be added to the emulsion as a dispersion described in No. 24185. Selective adsorption of dyes to specific crystallographic planes of emulsion grains as a means of limiting chemosensitization centers to other crystallographic planes, as described in published European patent application No. 302528 to Mifune et al. be able to. Published European patent application No. 2 by Miyasaka et al.
No. 70079, No. 270082 and No. 278510
Spectral sensitizing dyes can be used with poorly adsorbed luminescent dyes as described in US Pat.

The selection of specific spectral sensitizing dyes is described below: SS-1 Anhydro-5'-chloro-3'-di- (3-sulfopropyl) naphtho [1,2-d] -thiazolothiacyanine Hydroxide, sodium salt SS-2 Anhydro-5'-chloro-3'-di- (3-sulfopropyl) naphtho [1,2-d] -oxazolothiacyanine hydroxide, sodium salt SS-3 Anhydro-4 , 5-benzo-3′-methyl-4′-phenyl-1- (3-sulfopropyl) naphtho [1,2-
d] -thiazolo thiazolocyanine 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] -oxazolocarbocyanine 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-Sulfopropylbenzimidazoloxacarbocyanine hydroxide SS-11 anhydro-5,5'-dichloro-9-ethyl-3,
3'-di- (2-sulfoethyl-carbamoylmethyl)
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-ethyl-thiacarbocyanine 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 '
-Ethyl telluriacarbocyanine bromide SS-17 anhydro-5,6-methylenedioxy-9-ethyl-
3-Methyl-3 '-(3-sulfopropyl) tellurathiacarbocyanine hydroxide SS-18 3-ethyl-6,6'-dimethyl-3'-pentyl-
9,11-Neopentyrentyazicarbocyanine bromide SS-19 Anhydro-3-ethyl-9,11-neopentylene-
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-ethyl-oxacarbocyanine hydroxide, sodium salt SS-23 anhydro-5,5'-dichloro-3,3'-di- (3
-Sulfopropyl) -9-ethyl-thiacarbocyanine hydroxide, triethylammonium salt SS-24 anhydro-5,5'-dimethyl-3,3'-di- (3
-Sulfopropyl) -9-ethyl-thiacarbocyanine hydroxide, sodium salt SS-25 anhydro-5,6-dichloro-1-ethyl-3- (3
-Sulfobutyl) -1 '-(3-sulfopropyl) benzimidazolonaphthothio [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-phenyloxathiacarbo Cyanine p-toluenesulfonate SS-28 Anhydro-6,6'-dichloro-1,1'-diethyl-3,3'-di- (3-sulfopropyl) -5,5'-
Bis (trifluoromethyl) benzimidazole carbocyanine hydroxide, sodium salt SS-29 anhydro-5'-chloro-5-phenyl-3,3'-
Di- (3-sulfopropyl) oxathiacarbocyanine hydroxide, sodium salt SS-30 Anhydro-5,5'-dichloro-3,3'-di- (3
-Sulfopropyl) thiacyanine hydroxide, sodium salt SS-31 3-ethyl-5- [1,4-dihydro-1- (4-sulfobutyl) pyridine-4-ylidene] rhodannin, triethylammonium salt SS-321- Carboxyethyl-5- [2- (3-ethylbenzoxazoline-2-ylidene) -ethylidene] -3-phenylthiohydantoin SS-33 4- [2-((1,4-dihydro-1-dodecylpyridine-ylidene ) Ethylidene] -3-phenyl-2-isoxazolin-5-one SS-34 5- (3-ethylbenzoxazoline-2-ylidene)
-3-Phenylrhoddanine SS-35 1,3-Diethyl-5-{[1-ethyl-3- (3-sulfopropyl) benzimidazoline-2-ylidene] ethylidene} -2-thiobarbituric acid SS-36 5- [2- (3-Ethylbenzoxazoline-2-ylidene) ethylidene] -1-methyl-2-dimethylamino-4-oxo-3-phenylimidazolium 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) sulfonamide] -benzoxazoline-2-ylidene} ethylidene] acetonitrile SS-39 3-methyl-4- [2- (3-ethyl-5,6-dimethylbenzoterrazoline- 2-ylidene) 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- Sulfopropyl)
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-ylidene) ethylidene] thiazoline-2-ylidene} rhodanine, dipotassium salt SS-44 1,3-diethyl-5- [1-methyl-2 -(3,5-
Dimethylbenzoterrazoline-2-ylidene) ethylidene] -2-thiabarbituric acid SS-45 3-Methyl-4- [2- (3-ethyl-5,6-dimethylbenzotelrazoline-2-ylidene) -1 -Methylethylidene] -1-phenyl-2-pyrazolin-5-one SS-46 1,3-diethyl-5- (1-ethyl-2- (3-ethyl-5,6-dimethoxybenzoterrazoline-2- Ylidene) ethylidene] -2-thiobarbituric acid SS-47 3-ethyl-5-{[(ethylbenzothiazoline-2-
Ylidene) -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-methylbenzotelazoline-2-ylidene) -methyl]-[1-ethylnaphtho [1,2-d]- Tellrazolin-2-ylidene) methyl] methylene} rhodamine SS-50 anhydro-5,5′-diphenyl-3,3′-di-
(3-Sulfopropyl) thiacyanine hydroxide, triethylammonium salt SS-51 anhydro-5-chloro-5'-phenyl-3,3'-
Di- (3-sulfopropyl) thiacyanine hydroxide, triethylammonium salt Instability increasing the maximum density of negative emulsion coatings (ie,
Fog) can be prevented by incorporating stabilizers, antifoggants, antikink agents, latent image stabilizers and similar additives into the emulsion and adjacent layers prior to coating. Many antifoggants useful in the emulsions used in this invention can also be used in the developer, C.I. E. K. M
eer's The Theory of Photographic Process, 2nd
Edition, Macmillan, 1954, pp. 677-680,
It is classified under a few general headings. To avoid such instability in emulsion coatings, stabilizers and antifoggants can be used, which include, for example, halide ions (eg, bromide salts), Trivelli et al., US Pat. No. 2,566. 263, chloropalladate and chloropalladite, Jones, US Pat. No. 2,839,405 and Sideboth.
Allen, a water-soluble inorganic salt of magnesium, calcium, cadmium, cobalt, manganese and zinc as described in Am, U.S. Pat. No. 3,488,709.
U.S. Pat. No. 2,728,663 to Mercury Salt, Brown et al. To British Patent No. 1,336.
570 and Pollet et al., British Patent No. 1,
282,303, selenol and diselenide, Allen et al., U.S. Pat. No. 2,69.
4,716, Brooker et al. U.S. Pat. No. 2,131,038, Graham U.S. Pat. No. 3,342,596 and Arai et al. U.S. Pat. No. 3,954,478. Quaternary Ammonium Salts, Thiers et al., US Pat.
Azomethine desensitizing dyes described in 630,744, Herz et al., U.S. Pat. No. 3,220,839 and Kott et al., U.S. Pat. No. 2,514,65.
Isothiourea Derivatives Explained in No. 0, S
Thiazolidines described in cavron U.S. Pat. No. 3,565,625; peptide derivatives described in Maffet's U.S. Pat. No. 3,274,002; Welsh U.S. Pat. No. 3,161. 51
5 and Hood et al., U.S. Pat. No. 2,751,
Pyrimidines and 3-
Azotriazoles and azotetrazoles described in US Pat. No. 3,925,086 to Pyrazolidone, Baldassarri et al., US Pat. No. 2,444,605 to Heimbach, US Pat. No. 2,933, to Knott. 388, William
ms U.S. Pat. No. 3,202,512, Resear
ch Disclosure, Vol. 134, June 1975, Item 1345
2 and Vol. 148, August 1976, Item 14851, and Azaindene (especially tetraazaindene), Kendall et al. U.S. Pat. No. 2, as described in Nepker et al. , 40
3,927, Kennard et al., U.S. Pat. No. 3,266,897, Research Disclosure, V.
ol. 116, December 1973, Item 11684, Luckey.
U.S. Pat. No. 3,397,987 and Sa.
mercaptotetrazole, mercaptotriazole and mercapdiazole, described in US Pat. No. 3,708,303 to Lesin, Peterso.
US Pat. No. 2,271,229 to N. et al. and the azoles described in Research Disclosure, Item 11684, supra, Sheppard et al., US Pat.
319,090, Birr et al., U.S. Pat.
152,460, Research Disclosure,
Purines described in Item 13452 and French Patent No. 2,296,204 to Dostes et al., 1,3-Dihydroxy described in US Patent No. 3,926,635 to Saleck et al. (And / or 1,3-carbamoxy) -2-methylenepropane, and Gunther et al., U.S. Pat. No. 4,66.
Tellurazole, tellrazoline, tellurazolinium and tellurazolium salts described in US Pat. No. 1,438,438, Gunther US Pat. No. 4,581,330 and Przyklek-Elling et al. US Pat. No. 4,661,438 and Same as 4,677,20
An aromatic oxaterradinium salt as described in No. 2. Elemental Sulfur as described in published European Patent Application No. 294149 to Miyashi et al. And Published European Patent Application No. 297804 to Tanaka et al. And published European Patent Application No. 293917 to Nishikawa et al. The presence of thiosulphonate (particularly during chemical sensitization) can stabilize the high chloride emulsion.

Stabilizers that are particularly effective in gold-sensitized emulsions are benzothiazole, benzoxazole, naphthothiazole and Yutzy et al., US Pat.
Water-soluble gold compounds of certain merocyanine and cyanine dyes described in 7,915 and sulfinamides described in US Pat. No. 3,498,792 to Nishio et al.

Among other effective stabilizers in layers containing poly (alkylene oxide) are Carroll et al., US Pat. No. 2,716,062, British Patent No. 1,46.
6,024 and Habu et al., U.S. Pat.
Tetraazaindene (especially in combination with a Group VIII noble metal or resorcinol derivative) as described in 929,486, Quaternary ammonium as described in Piper US Pat. No. 2,886,437. Salt, Maffet U.S. Pat. No. 2,953,45
Water-insoluble hydroxide described in No. 5, Smith
U.S. Pat. Nos. 2,955,037 and 2,952
Phenols described in 5,038, Ders
ch. U.S. Pat. No. 3,582,346, ethylene diurea, Wood U.S. Pat. No. 3,61.
Barbituric acid derivatives described in US Pat. No. 7,290,290, Borane described in Bigelow, US Pat.
3-pyrazolidinone as described in US Pat. No. 158,059, as well as British Patent No. 988,052 to Butler et al.
Aldoximines, amides, anilides and esters described in the specification.

Emulsions of the invention are described in addition to additives such as the sulfocatechol-type compounds described in Kennard et al., US Pat. No. 3,236,652, Carroll et al., GB 623,448. Aldoximine Explained, US Patent No. 2,23 to Draisbach
Fog and copper, lead, tin, by incorporating the meta- and polyphosphates described in US Pat. No. 9,284, and carboxylic acids such as ethylenediaminetetraacetic acid described in British Patent No. 691,715. It is possible to prevent desensitization caused by a small amount of metal such as iron.

In layers containing synthetic polymers of the type used as vehicle and improving covering power, among other effective stabilizers are monovalent and polyvalent compounds described in Forsgard US Pat. No. 3,043,697. -Valent phenols, British Patent No. 897,497 and Stevens et al. British Patent No. 1,039,471.
And the quinoline derivatives described in US Pat. No. 3,446,618 to Dersch et al.

Particularly useful stabilizers for protecting emulsion layers against two-color fog are described in US Pat. Nos. 3,679,424 and 3,820,998 to Barbier et al. Nitron salt-like additives, Wi
llems et al., U.S. Pat. No. 3,600,178, and mercaptocarboxylic acids, as well as E.I. J. B
Stabilization of Photographic Silver Halid of irr
e Emulsions, Focal Press, London, 1974, pages 126-218.

Particularly useful stabilizers for protecting the emulsion layers against development fog are Bloom et al., GB 1,356,142 and US Pat. No. 3,57.
5,699, Rogers U.S. Pat. No. 3,4.
73,924 and additives such as azabenzimidazole described in Carlson et al., U.S. Pat. No. 3,649,267, Brooker et al., U.S. Pat. No. 2,131,038, Laud. U.S. Pat. No. 2,704,721, Rogers et al. U.S. Pat. No. 3,265,498, substituted benzimidazoles, benzothiazoles, benzothyrazoles, etc. 2,432,864, Rauch et al., U.S. Pat. No. 3,081,170, Weyerts et al., U.S. Pat. No. 3,260,597, Grassho.
ff, et al., U.S. Pat. No. 3,674,478 and Arondo, U.S. Pat. 3,2
Isothiourea derivatives described in U.S. Pat. No. 20,839, as well as von Kong US Patent 3,364,364.
No. 028 and von Kong et al., British Patent No. 1,186,441.

When using an aldehyde type curing agent,
Mono- and polyhydric phenols of the type described in Sheppard et al., U.S. Pat. No. 2,165,421, nitros of the type disclosed in Rees et al., British Patent No. 1,269,268. A substituted compound,
Poly (alkylene oxide) as described in Valbusa's British Patent 1,151,914, as well as All.
En et al., U.S. Pat. Nos. 3,232,761 and 3,
Such as mucohalogenic acid in combination with urazole as described in US Pat. No. 3,232,764, or mucohalogenic acid in combination with maleic hydrazide as further described in US Pat. No. 3,295,980 to Rees et al. The antifoggant can protect the emulsion layer.

Parabanic acid, hydantoic acid hydrazide and urazole, as described by Anderson et al., US Pat. No. 3,287,135, and two symmetrical layers, to protect the emulsion layers coated on the linear polyester support. Additives such as piazines with chemically fused 6-membered cyclic carbons, especially those in combination with aldehyde-type hardeners described in US Pat. No. 3,396,023 to Rees et al., Can be used. .

Kink desensitization of emulsions is described by Overman, US Pat. No. 2,628,167, thallium nitrate, Jones et al., US Pat. No. 2,759,8.
21 and 2,759,822, compounds of the type disclosed, polymer crystal lattices and dispersions, Re
search Disclosure, Vol. 116, December 1973, item
11684, hydrophilic colloidal dispersions of azole and mercaptotetrazole, of the type disclosed in US Pat. No. 3,033,680 to Milton et al., Plasticized gelatin compositions of the type disclosed in US Pat. Water-soluble copolymers of the type disclosed in 3,536,491, Pearson et al., U.S. Pat. No. 3,773.
Polymer crystal lattices prepared by emulsion polymerization in the presence of poly (alkylene oxide) as disclosed in US Pat. No. 3,832, Rakoczy.
It can be reduced by incorporating a gelatin graft copolymer of the type disclosed in 7,861.

When the photographic element is processed in a hot bath or dry temperature as in a fast access processor, pressure insensitivity and / or increased fog is
US Pat. No. 3,295,976 to Bbot et al.,
Barnes et al., U.S. Pat. No. 3,545,971, Salesin U.S. Pat. No. 3,708,303, Yamamoto et al. U.S. Pat.
619, Brown et al., U.S. Pat. No. 3,62.
No. 3,873, Taber US Pat. No. 3,673.
1,258, Abele, U.S. Pat. No. 3,79.
No. 1,830, Research Disclosure, Vol. 99,1
July 972, Item 9930, US Patent 3,843,364 to Florens et al., US Patent 3,867,152 to Priem et al., US Patent 3,967,965 to Adach et al. Description and Mika
U.S. Pat. Nos. 3,947,274 and 3,
Controlled by selected combinations of additives, vehicles, hardeners and / or processing conditions as described in US Pat. No. 954,474.

P, known to prevent latent image fading,
In addition to increasing H or lowering the pAg of the emulsion and adding gelatin, Ezekiel, British Patent Nos. 1,335,923, 1,378,35
No. 4, No. 1,378,654 and No. 1,391,6
72, Ezekiel et al., British Patent No. 1,39
4,371, Jefferson, U.S. Pat. No. 3,843,372, Jefferson et al., British Patent 1,412,294 and Thur.
Amino Acids Explained in Ston UK Patent No. 1,343,904, US Pat. No. 3,4 to Seiter et al.
Carbonyl-bisulfite addition products in combination with hydroxybenzene or aromatic amine developing agents, described in US Pat. No. 3,447,926 to Beckett et al. Cycloalkyl-1,3-diones, catalase-type enzymes described in US Pat. No. 3,600,182 to Matejec et al., US Pat. No. 3,881,933 to Kumai et al. A halogen-substituted curing agent in combination with certain cyanine dyes,
Hardeners described in Hong et al., US Pat. No. 3,386,831, Arai et al., US Pat. No. 3,953.
Alkenylbenzothiazolium salts described in US Pat. No. 4,478, Thurston, British Patent 1,30.
US Pat. No. 3,519,4 to Sutherns, a hydroxy-substituted benzylidene derivative as described in U.S. Pat. No. 8,777,773 and Ezekiel et al.
27. Mercapto-substituted compounds of the type disclosed in US Pat. No. 3,639, Matejec et al.
Metal-organic complexes of the type disclosed in 128, E
Zekiel's British Patent No. 1,389,089, penicillin derivatives, von Konig et al., U.S. Patent No. 3,910,791, benzimidazoles, pyrimidines and other propynylthio derivatives, Yamasue. U.S. Pat. No. 3,901,71
Combination of iridium and rhodium compounds disclosed in U.S. Patent No. 3,881,931 to Noda et al.
No. 9, sydnone or sydnonimine, the thiazolidine derivatives described in Ezekiel's British Patent No. 1,458,197, and Research.
Disclosure, Vol. 136, August 1975, latent image stabilizers such as thioether substituted imidazoles, described in item 13651, can be incorporated.

In addition to the features of tabular grain emulsion preparation methods specifically discussed, the tabular grains formed and the additional uses in photography can take any convenient conventional form. Possible to replace ordinary emulsions of the same or similar silver halide composition, replacing silver halide emulsions with different halogen compositions, especially other tabular grain emulsions are also possible in many types of photographic applications Is. The inherently low levels of blue sensitivity of the high chloride {100} tabular grain emulsions of this invention are found in both Ko in terms of layer sequence and the normal function of photographic elements containing tabular grain emulsions.
Any of the layer sequence orders disclosed in US Pat. No. 4,439,520 to Fron et al., which is hereby incorporated by reference, including those desired in a multicolor photographic element. Can be used in the order of layer arrangement. Normal function is explained by reference to the following disclosure: ICBR-1 Research Disclosure, Vol. 308, 1989.1
2, Item 308,119, ICBR-2 Research Disclosure, Vol.225, 1983.
1, Item 22,534, ICBR-3 Wey et al., U.S. Pat. No. 4,414,30
No. 6, (issued Nov. 8, 1983) ICBR-4 solberg et al., U.S. Pat. No. 4,43.
3,048, (issued February 21, 1984), ICBR-5 Wilgus et al., U.S. Pat. No. 4,43.
4,226, issued Feb. 28, 1984, ICBR-6 Mskasky, U.S. Pat. No. 4,43.
5,501, issued February 6, 1984, ICBR-7 Mskasky, U.S. Pat. No. 4,64.
3,996, (issued February 17, 1987), ICBR-8 Daubendiek, et al., U.S. Pat. No. 4,672,027, (issued January 9, 1987), ICBR-9 Daubendiek, etc. U.S. Pat. No. 4,693,964, issued Sep. 15, 1987, ICBR-10 Mskasky U.S. Pat. No. 4,71.
3,320, (December 15, 1987), ICBR-11 Saitou et al., U.S. Pat. No. 4,79.
7,354, issued Jan. 10, 1989, ICBR-12 Ikeda et al., U.S. Pat. No. 4,80.
6,461, issued Feb. 21, 1989, ICBR-13 Makino et al., U.S. Pat. No. 4,85.
3,322, (August 1, 1989), ICBR-14 Daubendiek et al., U.S. Pat. No. 4,914,014, (April 3, 1990).

Photographic elements comprising high chloride {100} tabular grain emulsions in accordance with this invention can be imagewise exposed using various forms of energy. The forms of energy include the ultraviolet, visible (eg actinic) and infrared regions of the electromagnetic spectrum and electron beam radiation, either incoherent (out of phase) or coherent (in phase), and β, γ, X Includes rays, alpha particles, and neutron energy. Exposure is monochromatic, color matching,
It can be full color. Imagewise exposure in a room, at high or low temperature and / or pressure, including high or low intensity exposure, continuous or intermittent exposure, exposure times over relatively short times from minutes to milliseconds to microseconds and overexposure. By TH James's The theory of t
he Photographic Process 4th edition, Macmillan, 1977,
It can be used within the useful response range determined by the usual sensitometric techniques described in chapters 4, 6, 17, 18 and 23.

[0112]

The invention can be better understood by reference to the following examples. By way of example, the abbreviation "APMT" is
1- (3-acetamidophenyl) -5-mercaptotetrazole is shown. Unless otherwise specified, the term "low methionine gelatin" is used to indicate gelatin which has been treated with an oxidizing agent to reduce its methionine content to less than 30 micromoles per gram. The abbreviation "DW" refers to distilled water. The abbreviation "mppm" refers to molar ppm. In some cases, the term "Rsens" is used to indicate relative sensitivity.

Example 1 This example illustrates an ultrathin tabular grain silver iodochloride emulsion satisfying the requirements of the invention. Low methionine gelatin 1.75% by weight,
And 0.011M sodium chloride, 1.48x10 ^{- 4} M
2030 ml of a solution containing potassium iodide was prepared in a stirred reaction vessel. The contents of the reaction vessel were maintained at 40 ° C. The pCl of the contents was 1.95.

While vigorously stirring this solution, 1.0M
30 ml of a silver nitrate solution and 30 ml of a solution containing 0.99 M sodium chloride and 0.01 M potassium iodide,
Each was added simultaneously at a rate of 30 ml / min. As a result, grain nucleation occurred, and crystals having an initial iodide concentration of 2 mol% with respect to the total silver amount could be formed. The mixture was then held at a temperature of 40 ° C for 10 minutes. After holding
A 1.0 M silver nitrate solution and a 1.0 M NaCl solution were added simultaneously at 2 ml / min over 40 minutes while maintaining the pCl at 1.95.

The resulting emulsion was a tabular grain silver iodochloride emulsion containing 0.5 mol% of iodide based on the amount of silver. 50% of the total grain projected area, selected based on the aspect ratio ranking of all {100} tabular grains with thickness less than 0.3 μm and major surface edge length ratio less than 10, has an average E
It was occupied by tabular grains having {100} major faces with a CD of 0.84 μm and an average thickness of 0.037 μm. The selected tabular grain population has an average aspect ratio (ECD / t) of 23 and an average tabularity (ECD / t ² ) of 6
It was 57. The major surface edge length ratio of the selected tabular grains was 1.4. 72% of the projected area of all particles is {1
00} major faces and aspect ratios of at least 7.5. These tabular grains have an average ECD of 0.75 μm and an average thickness of 0.045 μm.
m, average aspect ratio 18.6 and average flatness 488
Met.

A representative sample of emulsion grains is shown in FIG. Example 2 (Comparative) The emulsion of this example shows that iodide is important for the precipitation (nucleation) of the initial grain population. The same precipitation operation as in Example 1 was performed except that iodide was not added intentionally.

The resulting emulsion was cubic and consisted predominantly of square grains with a very small aspect ratio, with edge lengths in the range of about 0.1 to 0.5 μm.
There were small numbers of large rods and high aspect ratio {100} tabular grains, but not enough to make up an effective amount of grain populations. A representative sample of grains of this comparative emulsion is shown in FIG.

Examples 3-4 These examples demonstrate the effectiveness of iridium as a dopant to reduce low intensity reciprocity law failure (LIRF) when iridium is located near the grain surface. In these examples, LIRF was measured by comparing 1/10 second exposure and 10 second exposure. The three silver iodochloride {100} tabular grain emulsions used in these examples were prepared.
Table I shows the grain size and iodide content.

[0119]

Dopants for use in combination with Emulsions S-1, S-2 and S-3 to improve LIRF are listed in Table I.
Shown in I.

The following examples show the use of the above dopants in various amounts and in various positions during sensitization of emulsions S-1 to S-3. The sensitized emulsion was coated on a cellulose acetate film support. Upon coating, the emulsion layer was a tabular silver chloride emulsion 200 mg / ft ² (21.5 mg / dm ^2
2 ) to gelatin 500 mg / ft ² (53.8 mg / d
m ² ), and the overcoat is 100 mg / ft ² (10.8 mg / dm ² ) of gelatin and 0% bis (vinylsulfonylmethyl) ether as a hardening agent relative to the total amount of gelatin. It was comprised at a level of 0.5% by weight.

The coated photographic elements were subjected to a series of calibration (total energy) exposures ranging from 1/10 seconds to 10 seconds to evaluate the reciprocity law response of the coated photographic elements. The exposed film was treated with Hydroquinone-Eron ™ (p-N-methylaminophenol hemisulfate) developer for 6 minutes. Example 3 This example demonstrates the utility of the dopant D-2 added during spectral sensitization by the pCl cycle, which comprises sequentially adding chlorine ions, D-2, and silver ions. Compared to emulsions that are spectrally sensitized without the use of dopants or pCl cycles by the introduction of dopants in the pCl cycle or when the emulsions are the same but with the pCl cycle but without the dopants. An emulsion is formed that exhibits improved LIRF behavior.

Emulsion S-1 contained a portion of 5 parts per mol of silver.
Spectral sensitization was carried out by heat aging after treatment with 50 mg of blue spectral sensitizing dye DyeSS-1. Then APM
T was added in an amount of 90 mg per mole of silver. This is a control emulsion. S was performed in the same manner except that D-2 was contained by carrying out a pCl cycle consisting of adding 2 mol% of chloride and D-2 and then adding 2 mol% of silver ion.
The other part of -1 was spectrally sensitized. Such pCl cycles were performed before or after treating S-1 with the sensitizing dye. These samples are examples of the invention.

The final emulsion example was prepared by pCl cycling without dopant to demonstrate the effect of 2 mol% cycling without dopant effect. In Table III, pCl
The photographic results of D-2 added in various amounts by the cycling method are summarized.

Table III Example 3 Cycle D-2 Partial Before / After μg / Sensitivity # Dye Molar 365 nm White light LIRF 3/1 None None 160 160 30 3/2 After None 171 158 23 3/3 After 15 164 154 151 23 3/4 back 50 150 150 134 8 3/5 back 100 100 150 134 5 3/6 front 15 169 160 18 18 3/7 front 50 161 152 15 15 3/8 front 100 161 152 13

From Table III it is clear that the use of D-2 reduces the LIRF of the emulsion. Table III, I
The logarithm of the exposure dose required to obtain densities of 0.15 above the minimum densities of V, VI and XVIII of 10
The sensitivity is shown as 0 times. Example 4 In this example, the dopant D-1,
Shown is the utility in reducing LIRF when D-2 and D-3 were added to the spectral and chemical sensitizations of emulsions S-2 and S-3.

Separate portions of S-2 and S-3 were each added to 550 mg of the blue spectral sensitizing dye DyeSS per mole of silver.
Spectral sensitization was carried out by heat aging after treatment with -1. Then, add 2 mg / mol of colloidal gold sulfide reagent,
It was heat-aged at 60 ° C. for 30 minutes. Then increase the temperature to 40
The temperature was adjusted to ° C, and 90 mg of APMT was added per mol of silver. The resulting emulsion is an undoped emulsion for comparison with the doped emulsion.

2 mol% in which silver ion is added after chlorine ion addition before chemical sensitization step after dye addition step and ripening step
Another undoped emulsion was prepared in a similar manner except that the pCl cycle was performed. Spectrally and chemically sensitize the other part,
After subjecting to pCl cycles with various additions of dopant, APMT was treated as above.

Photographic results showing the improved LIRF of emulsions containing dopants D-1, D-2 and D-3 are summarized in Table IV. Also, a certain amount of D-1 and D-3
It is also worth noting that the sensitivity increases significantly with.

Table IV Example 4 vAg Dosage Partial Saipan μg / mole White Light # Emulsion Kurt Ag Sensitivity LIRF 4/1 S-2 No No 0 221 25 4/2 S-2 With No 0 231 19 4 / 3 With S-2 D-2 1500 205 6 4/4 With S-2 D-2 5000 155 4 4/5 S-3 Without Without 0 221 20 4/6 S-3 With D-1 15 231 12 4 / 7 S-3 Yes D-1 50 230 8 4/8 S-3 Yes D-1 100 233 14 4/9 S-3 Yes D-1 200 218 12 4/10 S-3 Yes D-3 5 243 9 4/11 S-3 Yes D-3 15 265 4 4/12 S-3 Yes D-3 50 239 2 4/13 S-3 Yes D-3 100 230 1

Example 5 This example demonstrates the effectiveness of iridium reduction of LIRF when iridium is included in the precipitation in a silver bromide Lippmann emulsion. Emulsion S-3 described in Example 4 was used as the host high chloride {100} tabular grain emulsion.

Lippmann silver bromide emulsion (edge length about 0.08 μm) with or without dopants
m) was prepared. Table V shows the Lippmann emulsion, the type of dopant and the amount of dopant contained in each emulsion. By blending the doped Lippmann emulsion and the undoped Lippmann emulsion, emulsions with various dope concentrations to be contained in the host AgCl {100} T-grain emulsion were obtained.

Table V Lippmann Size Dopant Dopant Amount Emulsion (μm) Chemical Formula Abbreviation MPPM L-1 0.08 Undoped --- 0 L-2 0.09 K ₃ IrCl ₆ D-1 200 L-3 0.09 K ₄ Ir ₂ Cl ₁₀ D -2 100

A part of the host emulsion S-3 was added to 550 mg of the blue spectral sensitizing dye DyeSS-1 per mol of silver.
It was spectrally and chemically sensitized by heating and aging it.
Then, 2 mg of colloidal gold sulfide reagent was added per mol of silver, and the mixture was heat-aged at 60 ° C. for 30 minutes. afterwards,
The temperature was adjusted to 40 ° C and 90 mg A per mol silver
PMT was added. The resulting emulsion is an undoped emulsion for comparison.

Another comparative emulsion was prepared in the same manner as above except that 2 mol% of undoped Lippmann silver bromide emulsion was added after the addition of colloidal gold sulfide and heat ripening.
After adding Lippmann emulsion, further heat ripening 60
It was performed at ° C for 10 minutes. Then the temperature was lowered to 40 ° C. and 90 mg APMT / mol silver was added. This comparative emulsion was prepared to show the effect of undoped Lippmann bromide on the S-3 host emulsion.

S-Similar to the above comparative example except that a doped Lippmann silver bromide emulsion or a blend of a doped Lippmann silver bromide emulsion and an undoped Lippmann silver bromide emulsion was added and ripened at 60 ° C. for 10 minutes. 3 Other parts of the host emulsion were sensitized. In Table VI, L when Dope Lippmann was added
The advantages in terms of IRF are shown. Application, exposure and treatment were carried out in the same manner as in Example 4.

Table VI Example 5 2% Dopant Dopant Dopant White Light Partial Lippmann Type Amount Sensitivity # Bromide (PPM) LIRF 5/1 No No 0 221 20 5/2 Yes No 0 233 20 5/3 Yes D-1 0.8 230 16 5/4 Yes D-1 2.0 238 10 5/5 Yes D-1 4.0 244 12 5/6 Yes D-2 0.4 237 17 5/7 Yes D-2 1.0 231 15 5/8 Yes D-2 2.0 239 11

As shown in Table IV, high chloride {10
Treatment of a 0} tabular grain host emulsion with an iridium-doped Lippmann silver bromide emulsion significantly reduces LIRF. Example 6 This example illustrates an emulsion according to the present invention in which 90% of the total grain projected area is comprised of tabular grains having {100} major faces and aspect ratios greater than 7.5.

3.52% by weight of low methionine gelatin,
And 0.0056M sodium chloride, 1.48x10 ^{- 4}
2030 ml of a solution containing M potassium iodide was prepared in a stirred reaction vessel. The contents of the reaction vessel were maintained at 40 ° C. The pCl of the contents was 2.25. While stirring this solution vigorously, 30m of 2.0M silver nitrate solution
1 and 30 ml of a solution containing 1.99 M sodium chloride and 0.01 M potassium iodide were added simultaneously at a rate of 60 ml / min each. As a result, grain nucleation occurred, and crystals having an initial iodide concentration of 1 mol% based on the total silver amount could be formed.

Next, this mixture was kept at a temperature of 40 ° C. for 10 minutes. After the holding, 0.5M silver nitrate solution and 0.5M NaCl solution were simultaneously added at 8 ml / min for 40 minutes while maintaining pCl at 2.35. Then, 0.5M AgNO ₃ solution and 0.5M NaCl solution were added simultaneously while maintaining the pCl at 2.35 and increasing the flow rate linearly from 8 ml / min to 16 ml / min over 130 minutes.

The obtained emulsion was a tabular grain silver iodochloride emulsion containing 0.06 mol% of iodide based on the amount of silver. 50% of the total grain projected area, selected based on the aspect ratio ranking of all {100} tabular grains with thickness less than 0.3 μm and major surface edge length ratio less than 10, has an average E
It was occupied by tabular grains having {100} major faces with a CD of 1.86 μm and an average thickness of 0.082 μm. The selected tabular grain population has an average aspect ratio (ECD / t) of 24 and an average tabularity (ECD / t ² ) of 3
It was 14. The major surface edge length ratio of the selected tabular grains was 1.2. 93% of the projected area of all particles is {1
00} major faces and aspect ratios of at least 7.5. These tabular grains have an average ECD of 1.47 μm and an average thickness of 0.086 μm.
m, average aspect ratio 17.5 and average flatness 222
Met.

Example 7 This example shows an emulsion prepared in the same manner as the emulsion of Example 3 except that the initial iodide concentration was 0.08 mol% and the final iodide concentration was 0.04 mol%. Low methionine gelatin 3.52% by weight, 0.0056M sodium chloride, 3.00x
10 ^{- 5} containing an M potassium iodide solution 2030ml
Was prepared in a stirred reaction vessel. 4 contents of the reaction vessel
Maintained at 0 ° C. The pCl of the contents was 2.25.

While vigorously stirring this solution, 5.0M
30 ml of silver nitrate solution and 30 ml of a solution containing 4.998 M sodium chloride and 0.002 M potassium iodide were added simultaneously at a rate of 60 ml / min each. As a result, grain nucleation occurred, and crystals having an initial iodide concentration of 0.08 mol% with respect to the total silver amount could be formed. The mixture was then held at a temperature of 40 ° C for 10 minutes.
After the holding, while maintaining pCl at 2.95, 0.5M silver nitrate solution and 0.5M sodium chloride solution were added at 8 ml /
Min. Was added simultaneously over 40 minutes.

The obtained emulsion was a tabular grain silver iodochloride emulsion containing 0.04 mol% of iodide based on the amount of silver. 50% of the total grain projected area, selected based on the aspect ratio ranking of all {100} tabular grains with thickness less than 0.3 μm and major surface edge length ratio less than 10, has an average E
It was occupied by tabular grains having {100} major faces with a CD of 0.67 μm and an average thickness of 0.035 μm. The selected tabular grain population has an average aspect ratio (ECD / t) of 20 and an average tabularity (ECD / t ² ) of 6
It was 51. The major surface edge length ratio of the selected tabular grains was 1.9. 52% of total particle projected area is {1
00} major faces and aspect ratios of at least 7.5. These tabular grains have an average ECD of 0.63 μm and an average thickness of 0.036 μm.
m, average aspect ratio 18.5 and average flatness 595
Met.

Example 8 In this example, the iodide concentration of the initial grain population was 6.0 mol%,
An emulsion in which the iodide concentration of the final emulsion is 1.6% is shown. Low methionine gelatin 3.52% by weight and 0.0056M
And sodium chloride, 3.00x10 ^{- 5} the solution 2030ml containing a M potassium iodide was provided in a stirred reaction vessel. The contents of the reaction vessel were maintained at 40 ° C. The pCl of the contents was 2.25.

While vigorously stirring this solution, 1.0M
30 ml of a silver nitrate solution and 30 ml of a solution containing 0.97M sodium chloride and 0.03M potassium iodide,
Each was added simultaneously at a rate of 60 ml / min. As a result, grain nucleation occurred, and crystals having an initial iodide concentration of 6.0 mol% with respect to the total silver amount could be formed. The mixture was then held at a temperature of 40 ° C for 10 minutes. After the holding, the 1.00M silver nitrate solution and the 1.00M sodium chloride solution were kept at 2 ml / mL while maintaining pCl at 2.35.
Min. Was added simultaneously over 40 minutes.

The resulting emulsion was a tabular grain silver iodochloride emulsion containing 1.6 mol% of iodide based on the amount of silver. 50% of the total grain projected area, selected based on the aspect ratio ranking of all {100} tabular grains with thickness less than 0.3 μm and major surface edge length ratio less than 10, has an average E
It was occupied by tabular grains having {100} major faces with a CD of 0.57 μm and an average thickness of 0.036 μm. The selected tabular grain population has an average aspect ratio (ECD / t) of 16.2 and an average tabularity (ECD / t).
t ² ) 494. The major surface edge length ratio of the selected tabular grains was 1.9. 62% of total particle projected area
Were 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 0.55 μm and an average thickness of 0.
The average aspect ratio was 041 μm, the average aspect ratio was 14.5, and the average flatness was 421.

Example 9 This example is an ultrathin high aspect ratio {100} plate having 2 mol% iodide present in the initial population and further iodide added during growth to a final iodide level of 5 mol%. Shows a grain-shaped emulsion. Low methionine gelatin 1.75% by weight, 0.00
And 56M sodium chloride, 1.48x10 ^{- 4} solution 2030ml containing a M potassium iodide was provided in a stirred reaction vessel. The contents of the reaction vessel were maintained at 40 ° C. The pCl of the contents was 2.2.

While vigorously stirring this solution, 1.0M
30 ml of a silver nitrate solution and 30 ml of a solution containing 0.99 M sodium chloride and 0.01 M potassium iodide,
Each was added simultaneously at a rate of 90 ml / min. As a result, grain nucleation occurred, and crystals having an initial iodide concentration of 2 mol% with respect to the total silver amount could be formed. The mixture was then held at a temperature of 40 ° C for 10 minutes. After holding
Maintaining pCl at 2.35 over 10 minutes,
A 1.00 M silver nitrate solution and a 1.00 M sodium chloride solution were simultaneously added at 8 ml / min and 3.375
x10 ^- was added at the same time of ² M potassium iodide in 14.6ml / min.

The obtained emulsion contains 5 parts of iodide with respect to the amount of silver.
It was a tabular grain silver iodochloride emulsion containing mol%. All {1 with a thickness less than 0.3 μm and a major surface edge length ratio less than 10
00} 50% of the total grain projected area selected based on the aspect ratio ranking of tabular grains has an average ECD of 0.58 µm and an average thickness of 0.030 µm {10
0} major faces were occupied by tabular grains. The selected tabular grain population has a mean aspect ratio (ECD
/ T) 20.6 and average flatness (ECD / t ² ) 803
Met. The major surface edge length ratio of the selected tabular grains is
It was 2. 87% of the total grain projected area consisted of tabular grains having {100} major faces and an aspect ratio of at least 7.5. These tabular grains had an average ECD of 0.54 μm, an average thickness of 0.033 μm, an average aspect ratio of 17.9 and an average tabularity of 803.

Example 10 In this example, 1 mol% of iodide was present in the initial grain population, and 50 mol% of bromide was added during the growth to give an iodide concentration of 0.3 mol% and a bromide concentration of 36 mol in the final emulsion. % And chloride concentration 63.7 mol% high aspect ratio {100} tabular grain emulsions.

3.52% by weight of low methionine gelatin,
And 0.0056M sodium chloride, 1.48x10 ^{- 4}
2030 ml of a solution containing M potassium iodide was prepared in a stirred reaction vessel. The contents of the reaction vessel were maintained at 40 ° C. The pCl of the contents was 2.25. While vigorously stirring this solution, 30m of 1.0M silver nitrate solution
1 and 30 ml of a solution containing 0.99 M sodium chloride and 0.01 M potassium iodide were simultaneously added at a rate of 60 ml / min each. This achieved grain nucleation.

Next, this mixture was kept at a temperature of 40 ° C. for 10 minutes. After the hold, 0.5M silver nitrate solution and a solution containing 0.25M sodium chloride and 0.25M sodium bromide were simultaneously added at 8 ml / min over 40 minutes while maintaining pCl at 2.60. As a result, crystals having an initial iodide concentration of 2 mol% with respect to the total silver amount were formed.

The resulting emulsion had an iodide content of 0.
This was a tabular grain silver iodobromochloride emulsion containing 27 mol% and 36 mol% of bromide, and the remaining halide being chloride. 50% of the total grain projected area, selected based on the aspect ratio ranking of all {100} tabular grains with thickness less than 0.3 μm and major surface edge length ratio less than 10, has an average E
It was occupied by tabular grains having {100} major faces with a CD of 0.4 μm and an average thickness of 0.032 μm. The selected tabular grain population has an average aspect ratio (ECD / t) of 12.8 and an average tabularity (ECD / t).
t ² ) 432. The major surface edge length ratio of the selected tabular grains was 1.9. 71% of total particle projected area
Were 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 0.38 μm and an average thickness of 0.
It had an average aspect ratio of 11.3 and an average flatness of 363.

Example 11 This example illustrates the preparation of an emulsion using phthalated gelatin as a peptizer that meets the requirements of the present invention. And phthalated gelatin 1.0% by weight were charged into a reaction vessel, and 0.0063M sodium chloride, 3.1 × 10 ^{- 4} and the stirred solution 310ml of 40 ° C containing MKI, while stirring, 0.
6.0 ml of a 1 M silver nitrate aqueous solution and 6.0 ml of a 0.11 M sodium chloride solution were simultaneously added at 6 ml / min.

Next, this mixture was kept at a temperature of 40 ° C. for 10 minutes. After holding, the pCl of the mixture is 2.7
While maintaining the flow rate of the silver solution and the salt solution at 3.0 m.
Linear increase from 1 / min to 9.0 ml / min was added simultaneously over 15 minutes. The resulting emulsion was a high aspect ratio tabular grain silver iodochloride emulsion. 50% of the total grain projected area 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 has an average ECD of 0.37 μm. Were occupied by 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 10 and an average tabularity (ECD / t ² ) 330. 70% of the total grain projected area consisted of tabular grains having {100} major faces and an aspect ratio of at least 7.5. These tabular grains had an average ECD of 0.3 μm, an average thickness of 0.04 μm and an average tabularity of 210.

When the square and rectangular surfaces of the tabular grains were examined by electron diffraction, it was confirmed that the main surface had a {100} crystal orientation. Example 12 This example illustrates the preparation of an emulsion using unmodified bone gelatin as a peptizer that meets the requirements of the invention.

Bone gelatin 0.69% by weight and 0.005
And 6M sodium chloride, 1.86x10 ^{- 4} containing a MKI, the solution 2910 is pH6.5 at a temperature of 55 ° C
60 ml of 4.0M silver nitrate aqueous solution and 60.0 ml of 4.0M sodium chloride solution in a vessel containing ml and stirring.
And were added simultaneously at 120 ml / min each. The mixture was then held for 5 minutes. 5000 m of solution containing 16.6 g / l low methionine gelatin during holding
1 was added and the pH was adjusted to 6.5 and pCl 2.25. After the hold, the silver and salt solutions were flowed from 10 ml / min to 2 while maintaining the pCl of the mixture at 2.25.
Linearly increased to 5.8 ml / min and added simultaneously over 63 minutes.

The resulting emulsion was a high aspect ratio tabular grain silver iodochloride emulsion containing 0.01 mol% iodide. About 65% of the total projected particle area has an average diameter of 1.5 μm
And tabular grains having an average thickness of 0.18 .mu.m. Example 13 This example compares the photographic performance of a {100} silver chloride tabular emulsion according to the present invention with the photographic performance of a silver chloride cubic grain emulsion of similar average grain volume.

Emulsion A. Silver iodochloride tabular emulsion with {100} major faces Precipitation (Example 3 emulsion re-prepared on a 3 × scale): 3.52 wt% low methionine gelatin, 0.0056
And M sodium chloride, 1.48x10 ^- were prepared in a ⁴ M solution 6090ml of 40 ° C containing a potassium iodide reaction vessel. While stirring the solution vigorously, 2.0
90 ml of M silver nitrate and 90 ml of a solution containing 1.99 M sodium chloride and 0.01 M potassium iodide,
Each was added simultaneously at a rate of 180 ml / min. The mixture was then held at a temperature of 40 ° C for 10 minutes.
After the holding, while maintaining the pCl at 2.35, 24 ml / 0.5M silver nitrate solution and 0.5M sodium chloride solution were added.
Flow rate from 24 ml / min to 4 after simultaneous addition for 40 min.
Linearly increased to 8 ml / min and added simultaneously over 130 minutes. Next, pCl was adjusted to 1.30 with sodium chloride, washed with water using ultrafiltration to adjust pCl to 2.0, and then pCl was adjusted to 1.65 with sodium chloride.
The obtained emulsion contains 0.06 mol% of iodide, has an average equivalent circular diameter of 1.45 μm and an average grain thickness of 0.13 μm.
It was a tabular grain silver chloride emulsion having

Sensitization: Sensitizing dyes, sodium thiosulfate pentahydrate, diammonium dithiosulfate dihydrate and a large number of small scale finishing experiments with varying holding times at 65 ° C. The optimum green light sensitization conditions for Emulsion A were found. The optimum finishing conditions were as follows. 0.800 was added to 0.5 mol of Emulsion A which was melted at 40 ° C. and sufficiently stirred.
After the addition of mmol / mol of green photosensitizing dye A, it was held for 20 minutes. To this was added 0.10 mg / mol sodium thiosulfate pentahydrate and 0.20 mg / mol sodium dithiosulfate ferrous gold dihydrate. Next, the temperature was raised to 65 ° C. over 9 minutes, then held at 65 ° C. for 4 minutes and rapidly cooled to 40 ° C.

Sensitizing dye A

[0163]

[Chemical 10]

Emulsion B. Silver chloride cubic grain emulsion (control) Precipitation: 8.2g sodium chloride, bone gelatin 2 while maintaining a temperature of 68.3 ° C and pCl 1.0.
A cubic edge length of 0 was obtained by simultaneously adding 3.75M silver nitrate and 3.75M sodium chloride to a well-stirred solution containing 8.2g / l and 0.212g / l 1,8-dithiadioctanediol. .59μ
m monodisperse silver chloride cubes were prepared. The temperature was lowered to 40 ° C and the emulsion was washed with water by ultrafiltration to obtain pCl2.0.
Then, the pCl was adjusted to 1.65 using sodium chloride.

Sensitization: In the same manner as described for Emulsion A, optimum green light sensitizing conditions were found. The optimum conditions were as follows. 0.2 mmol / mol of sensitizing dye A was added to 0.05 mol part of emulsion B melted at 40 ° C. and sufficiently stirred, and then held for 20 minutes. 0.25 to this
0.50 with mg / mol sodium thiosulfate pentahydrate
mg / mol sodium dithiosulfate ferrous gold dihydrate was added. The temperature was then raised to 65 ° C over 9 minutes, held for 10 minutes, and then rapidly cooled to 40 ° C.

[0166] Photographic Performance: Each sensitized emulsion, on antihalation support, silver 0.85 g / m ² of cyan dye-forming coupler C1.1g / m ^2, was coated with gelatin 2.7 g / m ^2. This was overcoated with 1.6 g / m ² of gelatin and hardened with 1.7% by weight of bis (vinylsulfonylmethyl) ether based on the total amount of gelatin.
The inherent sensitivity of the coating film was evaluated by exposing for 0.02 seconds with a step wedge sensitometer using a 365 nm line of a mercury lamp as a light source. A 3000 ° K tungsten tungsten bulb light is filtered so as to simulate a daylight V light source, filtered by a Kodak Ratten (trademark) 9 filter, and only green and red light is transmitted (transmission wavelength: over 450 nm). The sensitivity to green light was measured by exposing the coating for 0.02 seconds using a wedge sensitometer. British Journal of Photography Annual 1988 Edition (British.
Photog. Annual 1988), No. 196-
The coatings were processed using the Kodak Flexicolor ™ C-41 Color Negative Process described on page 198 and dye density was measured using Status M red filtration.

Coupler C

[0168]

[Chemical 11]

Photographic results are summarized in Table VII. Table VII Emulsion 365 line exposure Wratten (TM) 9 exposure Dmin Rsens controller Dmin Rsens contrast last Emulsion A (Tabular) unsensitized 0.06 10 1.75 --- --- --- green sensitized 0.22 129 1.96 .22 371 2.08 Emulsion B (cubic) Unsensitized 0.06 7 4.03 --- --- --- Green sensitized 0.22 120 2.89 .16 128 2.86

From Table VII, it can be seen that both the emulsions A and B are very similar in intrinsic sensitivity as measured by 365 line exposure, as expected from the similar grain volumes. From a comparison of green light sensitivities measured by Ratten ™ 9 exposure, tabular emulsions are 2.9 times more sensitive to green light than cubic emulsions. From this, the advantages of the flat plate are clear.

Example 14 This example shows the sensitization and photographic performance of a {100} silver chloride tabular emulsion sensitized with gold sulfide and a blue spectral sensitizing dye and a silver chloride cubic emulsion having a similar average grain volume. Explain and compare low silver coatings on resin coated paper supports. Precipitation of tabular silver chloride emulsions with {100} major faces: Example 1
In the same manner as the {100} silver chloride tabular emulsion described in 3,
This emulsion was prepared.

Precipitation of silver chloride cubic emulsion: 1, which is a ripening agent
This emulsion was prepared in the same manner as the cubic emulsion described in Example 13 except that 8-dithiadioctanediol was not used and the flow rate and precipitation time were adjusted so that emulsions of similar size were obtained. Sensitization: Both emulsions were blue light sensitized by the following procedure. A specific amount of each emulsion was melted at 40 ° C., and based on the specific surface area, 660 mg of sensitizing dye B {10
0} tabular emulsion added, the same dye 220 mg / mol
Was added to the cubic emulsion and held for 20 minutes. After 2.0 mg / mol of gold (I) sulfide was added to each emulsion, it was held for 5 minutes. Next, after raising the temperature to 60 ° C and holding for 30 minutes, APMT
90 mg / mol was added and the emulsion was cooled to solidify. Photographic properties: Each sensitized emulsion was coated on a resin-coated paper support with 0.28 g / m ² of silver and a yellow dye-forming coupler B1.1.
It was coated with g / m ² and gelatin 0.82 g / m ² . The inherent sensitivity of the coating film was evaluated by exposing for 0.1 second with a step wedge sensitometer using a 365 nm line of a mercury lamp as a light source. Sensitivity to white light was measured by exposing the coating for 0.1 second using a step wedge sensitometer equipped with a 3000 ° K tungsten bulb light. Standard R, as described in Research Disclosure, Vol. 308, p. 933, 1989.
The coatings were processed using the A-4 color paper process. Dye density was measured using standard reflection geometry and Status A filtration.

Photographic results are summarized in Table VIII. Table VIII Emulsion 365 line exposure 3000 ° K Tungsten exposure Dmin Rsens controller Dmin Rsens contrast last {100} tabular 0.08 98 2.53 .08 154 2.53 cubic 0.11 100 2.64 .11 100 2.64

From Table VIII, it can be seen that both the cubic and tabular emulsions are very similar in their intrinsic sensitivities measured by 365 line exposure, as expected from the similar grain volumes. . A comparison of the white light sensitivities measured by exposure to 3000 ° K tungsten shows that tabular emulsions have a sensitivity to blue light of about 50 that of cubic emulsions.
You can see that it is more than%.

Example 15 This example illustrates the method of adding bromide 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) This emulsion was prepared in the same manner as the {100} tabular emulsion described in Example 13. Next, a specific amount of this emulsion is melted at 40 ° C,
1200 mg / mol potassium bromide was added rapidly.
Next, 0.6 mmol of green sensitizing dye per mol of emulsion was added and held for 20 minutes. Next, after adding sodium thiosulfate pentahydrate 1.0 mg / mol and potassium tetrachloroaurate 1.3 mg / mol, the temperature was raised to 60 ° C. and kept for 10 minutes. The emulsion was then cooled to 40 ° C, 70 mg / mol APMT was added and the emulsion was cooled to solidify. When the crystal was examined by a scanning electron microscope, it was found that the edge of the crystal was roughened by the precipitation of bromide and a part of the surface was roughened.

Emulsion B (Invention) In this emulsion example, by adding potassium bromide during the final step of precipitation, most of the emulsion grains were epitaxially grown on 3 or 4 out of 4 corners of the tabular grain. Figure 3 shows the precipitation and sensitization of {100} silver chloride tabular emulsions forming emulsions with precipitates. Precipitation: Low methionine gelatin 3.52% by weight, 0.0
And 056M sodium chloride, 2.34x10 ^{- 4} a stirred solution 1536ml of pH5.74 with M potassium iodide containing a 40 ° C, was prepared in a reaction vessel. While stirring this solution vigorously, 30 ml of 2.0 M silver nitrate and 2.0 ml of
30 ml of M sodium chloride was added simultaneously at 60 ml / min each. This achieved nucleation.

Next, after holding this mixture for 10 seconds, pC
While maintaining 1 at 2.35, 0.5 M silver nitrate solution and 0.5 M sodium chloride solution were added at 6 ml at 5.3 ml / min.
Simultaneously added over 0 minutes. Next, a silver nitrate solution and a sodium chloride solution were added at a flow rate of 5.3 ml / min to 1
Addition was carried out over 150 minutes with a linear increase to 5.6 ml / min.

Next, the pCl was adjusted to 1.55 using sodium chloride, and 25 g of phthalated deionized gel was added and dissolved. Next, the pH was reduced to 3.85, stirring was stopped and the coagulate was allowed to settle. The supernatant was discarded and distilled water was added to the coagulum to make the initial volume at the end of precipitation. The stirring was restarted and the pH was adjusted to 5.36. pCl is 2.45
Met.

With vigorous stirring, 39 ml of a 1.5 M potassium bromide solution was added over 30 minutes to bring the pCl to 1.8. The pH was adjusted to 5.8, and 25 g of phthalated deionized gel was added and dissolved. The pH was reduced to 3.85, stirring was stopped and the coagulum was allowed to settle. The supernatant was discarded, 27 g of low methionine gel 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 1.0 with 1.0 M sodium chloride solution.
Adjusted to 65.

The obtained emulsion had an average equivalent circular diameter of 1.67.
mm and the average particle thickness was 0.135 mm. The halide composition is 93.964% silver chloride and 6.0% silver bromide.
And silver iodide was 0.0036%. 75% of the particles are
It had three or more small edges with epitaxial precipitates. Sensitization: 0.15 mol of emulsion was melted with stirring at 40 ° C. In addition, 0.70 mmol of green sensitizing dye A /
It was kept for 20 minutes after the addition of mol. Then, to this was added 1.0 mg / mol of sodium thiosulfate pentahydrate and 1.3 mg / mol of potassium tetrachloroaurate. Next, the temperature was raised to 60 ° C. over 12 minutes, held for 5 minutes, and then rapidly cooled to 40 ° C. Next, APMT70m
g / mol was added and the emulsion was cooled to solidify.

Emulsion C This emulsion example was prepared by adding potassium bromide during the final step of precipitation so that the majority of the emulsion grains had epitaxial precipitates located on only one or two of the small edges. 3 shows precipitation and sensitization of a {100} silver chloride tabular emulsion forming an emulsion. Precipitation: Low methionine gelatin 3.52% by weight, 0.0
And 056M sodium chloride, 2.34x10 ^{- 4} a stirred solution 1536ml of pH5.74 with M potassium iodide containing a 40 ° C, was prepared in a reaction vessel. While stirring this solution vigorously, 30 ml of 2.0 M silver nitrate and 2.0 ml of
30 ml of M sodium chloride was added simultaneously at 60 ml / min each. This achieved nucleation.

Next, after holding this mixture for 10 seconds, pC
While maintaining 1 at 2.35, 0.5 M silver nitrate solution and 0.5 M sodium chloride solution were added at 4 ml at 8.0 ml / min.
Simultaneously added over 0 minutes. Next, a silver nitrate solution and a sodium chloride solution were added at a flow rate of 8.0 ml / min to 1
It was added in a linear increment to 6.1 ml / min over 130 minutes.

Next, the pCl was adjusted to 1.65 by adding a sodium chloride solution at 20 ml / min for 8.0 minutes. After this, it was held for 10 minutes. The pCl was then increased to 2.15 by adding a silver nitrate solution at 5.0 ml / min for 27.7 minutes. After this, 1.5M
Potassium bromide solution was added at 2.0 ml / min over 20 minutes to bring the pCl to 1.70.

25 g of phthalated deionized gel was added and dissolved. Next, the pH was reduced to 3.85, stirring was stopped and the coagulum was allowed to settle. The supernatant was discarded and distilled water was added to the coagulum to make the initial volume. The pH was then adjusted to 5.7 with vigorous stirring again. Next, the pH was adjusted to 3.8 and stirring was stopped again to solidify. The supernatant was discarded again, 20 g of low methionine gel 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 1.0 with 1.0 M sodium chloride solution.
Adjusted to 65.

The obtained emulsion had an average equivalent circular diameter of 1.65.
mm and the average particle thickness was 0.14 mm. 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 revealed that 97% of the grains had epitaxial precipitates on no more than two of the four corners of the host tabular grains.

Sensitization: Prepared as Emulsion Example B, but increasing the levels of sodium thiosulfate pentahydrate and potassium tetrachloroaurate by 50%. Emulsion D (Control) This emulsion is composed of silver chloride cubic grains,
It was precipitated similarly to the cubic emulsion of Example 13 and has a grain volume similar to the three tabular emulsions of this example. This emulsion was sensitized as follows. A specific amount of this emulsion was melted at 40 ° C., potassium bromide (500 mg / mol) was added, and then sensitizing dye A (0.2 mg / mol) was added and held for 20 minutes. Add to this 0.25 mg of sodium thiosulfate pentahydrate.
/ Mol and 0.50 mg of sodium dithiosulfate ferrous gold
/ Mol was added, the temperature was raised to 65 ° C and
Hold for minutes. The emulsion was then quenched.

[0187] Photographic Performance: Each sensitized emulsion, on antihalation support, silver 0.85 g / m ² of cyan dye-forming coupler C1.1g / m ^2, was coated with gelatin 2.7 g / m ^2. This was overcoated with 1.6 g / m ² of gelatin to give 1.75% of the total weight of gelatin coated.
Cured with bis (vinylsulfonylmethyl) ether. The inherent sensitivity of the coating film was evaluated by exposing for 0.02 seconds with a step wedge sensitometer using a 365 nm line of a mercury lamp as a light source. A 3000 ° K tungsten bulb light is filtered so as to simulate a daylight V light source, filtered by a Kodak Ratten (trademark) 2B filter, and only light having a wavelength of more than 400 nm is transmitted.
Sensitivity to green light was measured by exposing the coating for 0.02 seconds using a step wedge sensitometer. The coating is then applied to Kodak Flexicolor ™ C-41.
Processed using a color negative process. Dye concentration was measured using Status M red filtration

Photographic results are summarized in Table IX. Table IX Emulsion Wratten (TM) 2B exposure 365 line exposure Dmin Rsens controller Dmin Rsens contrast last Emulsion A .14 200 2.22 .12 60 1.87 Emulsion B .13 275 2.05 .14 141 1.89 Emulsion C .12 245 2.36 .13 79 2.65 Emulsion D .14 100 2.82 .18 100 2.48 (control)

From Table IX it can be seen that all of the {100} tabular grain emulsion examples are at least two times more sensitive to white light exposure than similarly sensitized cubic grain emulsions. However, Emulsion A and Emulsion C had low intrinsic sensitivity to exposure to 365 mercury rays. Sensitizing dye B

[0190]

[Chemical 12]

TBA ⁺ = tributylammonium

[0192]

[Chemical 13]

Example 16 (Comparative Example) The purpose of this example was the aging method, specifically the 1963 Torino Symposium (Torino Symposium).
It is shown that the method referred to in m) cannot produce tabular grain emulsions which meet the requirements of this book. In a reaction vessel containing 75 ml of distilled water, 6.75 g of deionized bone gelatin and 2.25 of 1.0M NaCl solution at 40 ° C.
ml at the same time with sufficient stirring to give 1.0 MA
15 ml of gNO ₃ solution and 15 ml of 1.0M NaCl solution
And 15 ml / min each were added. After stirring the mixture at 40 ° C for 4 minutes, the temperature was increased to 77 ° C over 10 minutes and 7.2 ml of 1.0 M NaCl solution was added. The mixture was stirred at 77 ° C for 180 minutes and then cooled to 40 ° C.

The resulting particle mixture was examined by optical and electron microscopy. As a result, the emulsion has an edge length of about 0.2 μm.
Of small cubes, large non-tabular grains and tabular grain emulsions of square or rectangular major faces. In terms of particle number, small particles accounted for the overwhelming proportion. The tabular grain proportion was only 25% of the total grain projected area of the emulsion.

The average thickness of the tabular grain population was obtained using an electron microscope, and an edge-on view was obtained.
w). When a total of 26 tabular grains were measured, the average thickness was 0.38 μm. Of the 26 tabular grains whose thickness was measured, only one had a thickness of 0.3 μm.
And the thickness of the tabular grains was 0.25 μm.

Example 17 The purpose of this example is to show that commercially available deionized gelatin can be used as a raw material to prepare emulsions which meet the requirements of the invention. To a reaction vessel equipped with a stirrer was added 2865 g of distilled water containing 20 g of deionized gelatin (purchased from Rosettet ™). The initial calcium ion level was 8x10 ^-6 molar. Additional calcium ions were added to the reaction vessel with calcium chloride hydrate to make up for the calcium ions removed during gelatin deionization to bring the calcium ion concentration up to 2.36 millimolar. Sodium chloride 0.96
The addition of 45 g of 0.012 molar potassium iodide solution completed the adjustment of the dispersion medium in the reaction vessel. The pH was adjusted to 6.5 at 55 ° C and sodium hydroxide solution or nitric acid solution was added to adjust the pH value during precipitation to 6.
Maintained at 5.

A 4.0 M silver nitrate solution and a 4.0 M sodium chloride solution were added over 30 minutes at a rate of consuming 5% of the total silver. The emulsion was then held at 62 ° C for 10 minutes and then a solution containing 1.6% deionized gelatin 5000
g was added. Then, while maintaining pAg at 6.37, silver nitrate and sodium chloride were added at 2.58 for 70 minutes.
The dose was linearly increased and added at the same time. The total amount of silver iodochloride precipitated was 4.745 mol.

The ratio of more than 80% of the total grain projected area is
It was occupied by tabular grains. Tabular grains have average ECD
The average thickness was 1.65 μm, the average thickness was 0.165 μm, and the average aspect ratio was 10. When the above-described preparation operation was repeated except that calcium acetate was used instead of calcium chloride hydrate, tabular grains accounted for more than 85% of the total grain projected area. Tabular grains have an average EC
D1.5 μm, average thickness 0.16 μm, and average aspect ratio 9.4. Even when magnesium, aluminum or iron ions were used in place of calcium ions in the dispersion medium, it was found that the requirements of the present invention were satisfied.

Examples 18 and 19 These examples show high flatness (>) according to the production method of the present invention.
25), showing the preparation of a medium aspect ratio tabular grain emulsion. Example 18 3.52% by weight low methionine gelatin, 0.0056
And M sodium chloride, 1.48x10 ^- were prepared in a ⁴ M solution 6090ml of 40 ° C containing a potassium iodide reaction vessel. While stirring the solution vigorously, 2.0
90 ml of M silver nitrate and 90 ml of a solution containing 1.99 M sodium chloride and 0.01 M potassium iodide,
Each was added simultaneously at a rate of 180 ml / min. The mixture was then held at a temperature of 40 ° C for 10 minutes.
After the holding, while maintaining pCl at 2.25, 12 ml of 1.0M silver nitrate solution and 1.0M sodium chloride solution were added.
Flow rate from 12 ml / min to 3 after simultaneous addition for 40 min.
Linearly increased to 3.7 ml / min and added simultaneously over 233.2 minutes. Next, pCl was adjusted to 1.30 with sodium chloride, washed with water using ultrafiltration to adjust pCl to 2.0, and then pCl was adjusted to 1.65 with sodium chloride. The resulting emulsion contained 0.03 mol% iodide, had an average equivalent circular diameter of 1.51 μm and an average thickness of 0.2.
It was a tabular grain silver chloride emulsion having a size of 2 μm. The average aspect ratio was 6.9 and the average flatness was 31.

Example 19 3.52% by weight low methionine (sodium hydroxide treated) gelatin, 0.0056M sodium chloride,
2.34x10 ^{- 4} and M potassium iodide was provided a solution 1536ml of 40 ° C containing a polyethylene glycol antifoam 0.3ml to the reaction vessel. While stirring the solution vigorously, 30 ml of 2.0 M silver nitrate and 2.
30 ml of 0M sodium chloride solution, 60 ml / each
It was added simultaneously at the rate of minutes. Next, this mixture is mixed with 10
Hold for a second. After the holding, 0.5M silver nitrate solution and 0.5M sodium chloride solution were simultaneously added at 8 ml / min for 40 minutes while maintaining pCl at 2.25. Then pC
1 was adjusted to 1.65 with 1.0 M sodium chloride. Next, 0.5M silver nitrate and 0.5M sodium chloride were added initially at 8 ml / min with a linear increase in flow rate of 0.0615 ml / min while maintaining the pCl at 1.65. After 90 minutes, microscopic observation of the emulsion revealed that the equivalent circular diameter was 0.9 μm and the average grain thickness was 0.17 μm.
The average aspect ratio at this point was 5.3 and the flatness was 31.

Examples 20 and 21 These examples show that the ECD was 2 μm by premixing the growth reactants in a continuous reactor before adding them to the growth reactor.
7 shows the preparation of emulsions that meet the requirements of this invention using a dual zone growth process that yields tabular grains in excess of 1. Example 20 Bone gelatin concentration 1.77 wt%, sodium chloride concentration 0.0056 M, potassium iodide concentration 1.86x10 ^{- 4}
M, temperature 55 ° C and pH 6.5 with stirring solution 294
In a container containing 5 ml, 15 ml of 4.0 M silver nitrate solution and 15 ml of 4.0 M sodium chloride solution were respectively added to 30 m.
Simultaneously added at 1 / min.

The mixture was then held for 5 minutes while maintaining pCl 2.15 and pH 6.5. During the hold, 7,000 ml of distilled water was added and the temperature was raised to 65 ° C. After holding, it was grown using a dual zone process to increase the size of the resulting particles. In this process, a 0.67M silver nitrate solution was premixed with a 0.67M sodium chloride solution and a 0.5 wt% bone gelatin solution at pH 6.5 in a continuous reactor with a total volume of 30 ml. The effluent from this premix reactor was then added to the first reactor. During this process, this reactor served as a growth reactor. During the growth process, crystallites from the continuous reactor were aged on the first crystal by Ostwald ripening. During this growth process, the total suspension volume of the growth reactor was maintained at a constant value of 13.5 liters using ultrafiltration.

The flow rates of the 0.67 M silver nitrate solution and the 0.67 M sodium chloride solution were increased linearly from 20 ml / min to 80 ml / min, 150 ml / min and 240 ml / min at 25 min intervals. The flow rate of the 0.5% gelatin reactant is
It was kept constant at 500 ml / min. A continuous reactor premixed with these reactants was maintained at 30 ° C and pCl 2.45, while the growth reactor was maintained at 65 ° C, pCl 2.
Maintained at 2.15 and pH 6.5.

By this operation, 6 mol of a high aspect ratio tabular grain iodochloride emulsion having an iodide concentration of 0.01 mol% was obtained. The ratio of more than 90% of the total projected grain area is {1
00} major faces and occupied by tabular grains having an average ECD of 2.55 μm and an average thickness of 0.165 μm. Therefore, the tabular grain population has an average aspect ratio of 15.
5 and the average flatness was 93.7.

Example 21 0.447 M silver nitrate solution (100 ml / min) at 0.43 M pCl 2.3 and 40 ° C. temperature, a solution containing 0.487 M sodium chloride and 0.00377 M potassium iodide (100 ml / min) and Silver iodochloride nuclei were formed by mixing 2.0 wt% bone gelatin solution (1 liter / min) in a 30 ml well-stirred continuous reactor. The resulting mixture containing nuclei was transferred to a semi-batch reactor and stirred for 1.5 minutes. The semi-batch reactor was maintained at 65 ° C and a constant volume of 13.5 liters (using ultrafiltration). The initial pCl was 2.15, pH 6.5 and bone gelatin concentration 0.37% by weight. The 1M sodium chloride solution was added to maintain the pCl of the latter at 2.15 while transferring the nuclei from the continuous reactor to the semi-batch reactor.

After holding for 5 minutes, initial nuclei growth was achieved by the following dual zone process. 0.67M silver nitrate solution, 0.67M sodium chloride solution and pH 6.5
Of 0.5% by weight bone gelatin solution were premixed in a 30 ml continuous reactor and then transferred to a semi-batch reactor. Ostwald ripening caused growth, which caused crystals from the continuous reactor to dissolve in the semi-batch reactor, increasing the initial nucleus size. During this step, the nucleation step, the total suspension volume of the semi-batch reactor was kept constant at 13.5 liters.

During the growth step, a 0.67 M silver nitrate solution was added to the solution.
The flow rate of the 67M sodium chloride solution is 20 ml / min to 80 ml / min, 150 ml / min and 240 at 25 min intervals.
Increased linearly to ml / min. The 0.5% gelatin reactant flow rate was kept constant at 500 ml / min. A continuous reactor premixed with these reactants was run at 30 ° C and pC.
12.45 while maintaining the growth reactor at a temperature of 65
Maintained at ° C, pCl 2.15 and pH 6.5.

By this operation, tabular grain iodochloride emulsion 6 having a large and high aspect ratio of iodide concentration of 0.01 mol% was obtained.
A mole was obtained. Over 80% of the total projected grain area was accounted for by tabular grains having {100} major faces and having an average ECD of 2.28 μm and an average thickness of 0.195 μm. Thus, the tabular grain population had an average aspect ratio of 11.7 and an average tabularity of 60.0.

[Brief description of drawings]

FIG. 1 is a shaded micrograph of a carbon grain replica of an emulsion having grain characteristics of the present invention.

FIG. 2 is a shaded micrograph of a carbon grain replica of a control emulsion.

Claims (10)

[Claims] 1. A radiation sensitive emulsion comprising a silver halide grain population comprising at least 50 mol% chloride based on total silver forming the grain population projected area, the radiation sensitive emulsion comprising at least 50% of the total grain projected area. Are (1) bounded by {100} major faces having adjacent edge ratios less than 10, (2) each having an aspect ratio of at least 2, and (3) adjacent cation positions in their crystal lattice. And a tabular grain averaging at least a pair of metal ions selected from the 5th and 6th periods of Group 8 in the radiation-sensitive emulsion. 2. The radiation-sensitive emulsion according to claim 1, further characterized in that at least 5 pairs of adjacent cation positions of the crystal lattice are occupied by Group 8 Group 5 and 6 metal ions. 3. A radiation-sensitive emulsion according to claim 2, further characterized in that at least 10 pairs of adjacent cation positions of the crystal lattice are occupied by Group 8 Group 5 and 6 metal ions. 4. The radiation-sensitive emulsion according to claim 1, wherein the Group 8 metal ion is an iridium ion. 5. At least one of 2 to 20 said Group 8 metal ions, each occupying at least one adjacent non-Group 8 metal ion a cation position located within the face-centered cubic crystal lattice structure. The radiation-sensitive emulsion according to any one of claims 1 to 4, further characterized in that the grains contain one of the grains. 6. At least one of 6-10 of said Group 8 metal ions, each occupying a cation position located within the face-centered cubic crystal lattice structure in at least one adjacent non-Group 8 metal ion. The radiation-sensitive emulsion according to any one of claims 1 to 5, further characterized in that the grains contain one of them. 7. The face-centered cubic lattice structure further comprising an anion between adjacent cation position Group 8 metal ions different from the remaining anions in the face-centered cubic lattice structure. The radiation-sensitive emulsion according to any one of 1. 8. The radiation-sensitive emulsion according to claim 7, wherein the anion between the adjacent cation-position Group 8 metal ions is a halide ion. 9. At least 50% of the total grain projected area is
(1) bounded by {100} major faces having adjacent edge ratios less than 10, (2) each having an aspect ratio of at least 2, (3) eighth at adjacent cation positions in their crystal lattice. Averagely containing at least one pair of metal ions selected from the 5th and 6th periods of the group, and (4) iodide and at least 5 at the nucleation position inside.
Silver halide grains characterized by being occupied by tabular grains containing 0 mol% chloride, (a) iodide together with chloride accounting for at least 50 mol% of the chloride present in the dispersing medium. PC of presence and of dispersion medium
introducing silver and halide salts into the dispersing medium such that nucleation of the tabular grains occurs while maintaining l in the range of 0.5 to 3.5, (b) following nucleation A step of completing grain growth under conditions that maintain the {100} major faces of tabular grains, and (c) at least one of steps (a) and (b) in a dispersion medium, Introducing an oligomer of a Group 5 or 6 period metal, wherein each oligomer comprises at least two metal ions, and at least two metal ions are averaged to each particle at adjacent cation positions. A method of preparing a radiation-sensitive emulsion containing a dispersion medium and silver halide grains, prepared by a process comprising: incorporating. 10. The anion oligomer has the following formula: M ₂ L ₁₀ , M ₆ L ₂₄ , M ₈ L ₃₂ , and M ₁₀ L ₃₈ , wherein M is a Group 8, 5 or 6 periodic element. And L is selected from those satisfying the formula (4), and L is a bridging ligand. 10. The method for preparing a radiation-sensitive emulsion according to claim 9, further characterized by: