JPH055096B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a photosensitive silver halide emulsion, and more particularly to a photosensitive silver halide emulsion that is highly sensitive and less likely to develop fog due to pressure or friction. In recent years, as color negative films have become smaller in format, there has been a strong demand for silver halide light-sensitive materials with excellent graininess and sharpness. Furthermore, as silver resources are becoming increasingly depleted, there is a need for the development of photographic materials containing a low amount of silver. Furthermore, there is a demand for color negative photosensitive materials with high sensitivity and low fog for use in taking photographs under adverse conditions with little light, such as indoors. Various studies have been conducted for these purposes, and results have been achieved using monodisperse emulsions or mixed systems of monodisperse emulsions. However, in addition to these effects, the occurrence of fog due to pressure and friction increases during the coating Γ drying process, packaging process, photography, development process, etc., which has a fatal effect on photographic images. The present invention attempts to solve the problems of these incompatible photographic materials. [Prior Art] The most traditional way to achieve photographic performance with high sensitivity and excellent graininess, low fog, or a light-sensitive material with a low silver content is to improve the quantum efficiency of silver halide. For this purpose, knowledge of solid state physics is actively incorporated. Research that theoretically calculated this quantum efficiency and considered the influence of particle size distribution was published, for example, in the Proceedings of the 1980 Tokyo Symposium on Advances in Photography, "Interactions Between Light and Materials for Photographs." It is described on page 91 of ``Itsuku Applications''. According to this research, it is predicted that creating a monodisperse emulsion by narrowing the particle size distribution will be effective in improving quantum efficiency.
In addition, monodisperse emulsions are advantageous in order to efficiently achieve high sensitivity while maintaining low fog in a process called scientific sensitization to achieve sensitization of silver halide emulsions. The inference that this is the case is also considered to be reasonable. For this reason, in recent years, much research has been conducted on manufacturing techniques for monodisperse silver halide emulsions and the design of photosensitive materials using monodisperse emulsions. That is,
Monodisperse silver halide grains can be obtained with a desired size by adding a water-soluble silver salt and a water-soluble halide by a double jet method while controlling pAg and PH. In addition, highly monodisperse silver halide emulsions were developed in JP-A-54-
The method described in Publication No. 48521 can be applied. A preferred embodiment of the method is a method in which a potassium iodobromide-gelatin aqueous solution and an ammoniacal silver nitrate aqueous solution are added to a gelatin aqueous solution containing silver halide seed particles while changing the addition rate as a function of time. Manufacture by hand.
At this time, a highly monodisperse silver halide emulsion can be obtained by appropriately selecting the time function of addition rate, PH, pAg, temperature, etc. Such techniques are known. On the other hand, in order to provide a light-sensitive material with high sensitivity and excellent sharpness, studies have been conducted on combinations of grain sizes of silver halide grains that minimize light scattering. The Theory of the
Photographic Process 4th Ed.James P.584,
Examples include the specification of US Pat. No. 3,402,046. Further, it is known that the best method for obtaining an optimum silver halide grain size distribution for improving sharpness is to combine a silver halide emulsion consisting of monodisperse silver halide grains. Despite this theoretical prediction of excellent performance and the extensive research that has been conducted, there are few studies that utilize monodispersed emulsions alone or as a mixture, and in particular, none of them utilize negative high-speed emulsions. It's okay. As mentioned above, one of the reasons for hindering the industrialization of monodisperse emulsions is the occurrence of fog due to pressure and friction during the coating/drying process, packaging process, photographing, and development process. The problem of fogging caused by pressure, friction, etc. generally increases as the quantum efficiency of silver halide grains increases, and also increases as the size of silver halide grains increases and absolute sensitivity increases. The photographic performance expected of the monodisperse emulsion and the means for achieving it, as described above, are in conflict with and contradictory to this problem. [Object of the Invention] Therefore, an object of the present invention is to provide a silver halide emulsion that has high sensitivity, low fog, and exhibits excellent graininess and sharpness. [Structure of the Invention] The present inventors have conducted research to improve monodisperse emulsions that have desirable characteristics in terms of photographic performance but have a fatal defect of fogging due to pressure or friction. A monodispersed emulsion having monodispersed silver halide grains in which the vertices of the crystal faces of cubic crystals and/or 14-sided crystals having octagonal and triangular crystal faces are slightly rounded by treatment with a silver halide solvent. It has been found that the above objects of the present invention can be achieved by a silver halide emulsion characterized by the following. In the present invention, the silver halide grains having tetradecahedral crystals are mainly composed of (100) planes, that is, they have an octagonal and triangular appearance. The apex of the crystal face of a cubic crystal or a tetradecahedral crystal is slightly rounded. In a cubic crystal, the radius of curvature of any corner of any one quadrangle on the outer surface of the cubic crystal is Assuming a quadrilateral by extending the sides, and let one side be r, it means that it is 1/10r to 1/6r of the circle inscribed on that side, and in the case of a tetradecahedral crystal, the 3 When focusing on the polygon with the largest area among the polygons and octagons, the radius of curvature of the corner of that polygon is assumed to be a polygon by extending the sides, and one side is r, or the radius of curvature of the corner of that polygon is If it is not a polygon, it is 1/10r to 1/6r of the circle inscribed in that side, where r is the largest side. The silver halide emulsion according to the present invention is preferably an emulsion in which 20% or more (by number) of the silver halide grains contained therein are silver halide grains having such roundness, and the silver halide emulsion is The same applies to the degree of treatment (hereinafter referred to as solvent treatment). The breadth of the grain size distribution of silver halide contained in the monodispersed silver halide emulsion according to the present invention is as follows:
When expressed by the coefficient of variation CV, which is expressed by the relational expression (standard deviation/average particle size) x 100 = CV%, it has monodispersity with a CV of 24% or less, and more preferably a CV of 18% or less. be. If it exceeds this range, the excellent characteristics of a monodisperse emulsion will be lost and the object of the present invention will not be achieved. Note that the grain size is the diameter of a circumscribed circle in an electron micrograph of a silver halide grain. In the production of the silver halide emulsion of the present invention, the monodisperse silver halide emulsion treated with a solvent is prepared such that the silver halide grains contained in the emulsion are substantially composed of cubic or tetradecahedral silver halide grains. It is preferable that Note that irregularly shaped particles may be contained within a range that does not impair the effects of the present invention. The width of the grain size distribution of the silver halide grains contained in the monodisperse silver halide emulsion to be subjected to solvent treatment is determined by the width of the distribution after the solvent treatment, which is defined as CV=
It is sufficient that the value is not more than 24, for example, CV is not more than 20%, more preferably not more than 15%. In the production of the silver halide emulsion of the present invention, solvent treatment is mixing, or adding a solvent for silver halide to the silver halide emulsion in which the silver halide grains have reached their final size and shape after mixing and physical ripening. The solvent may be added and mixed uniformly to act on the surface of the silver halide grains, and the operation may be similar to the operation in which a solvent is used instead of a chemical sensitizer in ordinary chemical ripening. Note that after the silver halide grains are formed, the silver halide emulsion before being subjected to solvent treatment may be desalted (including washing with water). The solvent for silver halide used in the present invention may be any solvent that, when acting on the surface of cubic or tetradecahedral silver halide grains, forms a roundness at the apex of the crystal plane on the surface of the grain. . Note that the solvent is preferably a compound that does not react with silver halide to produce silver sulfide. The silver halide solvent used in the present invention is
(a) U.S. Patent No. 3271157, U.S. Patent No. 3531289, U.S. Patent No.
Specifications of No. 3574628, JP-A-54-1019 and JP-A No. 54
-Organic thioethers described in each publication No. 158917, (b) JP-A-53-82408, JP-A-55-77737 and JP-A No. 55-77737;
Thiourea derivatives described in various publications such as No. 55-29829, (c) AgX solvent having a thiocarbonyl group sandwiched between an oxygen or sulfur atom and a nitrogen atom described in JP-A No. 53-144319, (d) Japanese Patent Publication No. 1973-
Imidazoles described in JP-A No. 100717, (e) sulfites, (f) thiocyanates, (g) ammonia, (h) hydroxyalkyl-substituted ethylenediamines described in JP-A-57-196228, (i) ) Japanese Patent Publication No. 1987
Examples include substituted mercaptotetrazoles described in JP-A-202531. Next, specific examples of these silver halide solvents (a) to (i) will be given. HO-( _CH2 ) ₂ -S-( _CH2 ) _2- S-( _CH2 ) ₂ -OH

【formula】

【formula】

【formula】 【formula】

【formula】

【formula】 [Exemplary DIR compounds]

The light-sensitive material prepared using the emulsion of the present invention may have any conventionally known layer structure. After exposure, this photosensitive material can be developed by a commonly used known method. The black and white developer is an alkaline solution containing developing agents such as hydroxybenzenes, aminophenols, and aminobenzenes, and may also contain other alkali metal salts such as sulfites, carbonates, bisulfites, bromides, and iodides. can. Further, when the light-sensitive material is for color use, color development can be carried out by a commonly used color development method. In the reversal method, the image is first developed using a black-and-white negative development method, then exposed to white light or treated with a bath containing a fogging agent, and then color developed using an alkaline developer containing a color developing agent. There are no particular restrictions on the processing method, and any processing method can be applied, but typical examples include a method in which bleach-fixing is performed after color development, followed by washing with water and stabilization treatment if necessary, or color development. After that, bleaching and fixing can be carried out separately, and if necessary, washing with water and stabilizing treatment can be carried out. [Example] Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto. Example 1 A monodisperse cubic silver iodobromide emulsion having an average grain size of 0.25μ and containing 2 mol% of silver iodide was used as seed grains, and ammonia was mixed with AgX.
As a solvent, the silver iodide content is 8 using the double jet method.
A core/shell type monodisperse silver iodobromide emulsion having an average grain size of 0.8 μm and having a core of mol % and a shell of pure silver bromide was prepared. During production, pAg was maintained at 9.0 until 50% of silver nitrate was added, and thereafter at 10.3. In addition, the pH during manufacturing was maintained at 9.0. The average shell thickness of the silver halide grains contained in this emulsion is 0.02μ, and the grain size is an inclusion mainly composed of cubic crystals and tetradecahedral crystals with an octagonal and triangular appearance, and a grain size distribution of 17 It was %. This emulsion was divided into three parts, rhodanammonium and a thioether represented by the following formula were added, and the mixture was aged at 50°C, followed by desalting and washing with water in a conventional manner, and the pAg was adjusted to 8.2 at 40°C. These emulsions are designated Em-1 to Em-3. Table 1 shows the amounts of rhodanammonium and thioether [] added and the observation results of the particle shape after treatment using an electron microscope. Next, 0.25 ml of 0.2% chloroauric acid/tetrahydrate aqueous solution and 0.4 ml of 0.25% sodium thiosulfate/dihydrate aqueous solution were added per mol of AgX, and 1
% rhodan ammonium aqueous solution was added and chemical ripening was performed at 46°C. Next, each emulsion was divided into three parts, and the following spectral sensitizing dyes (1) to (3) were added as a methanol solution at 150 mg per mole of AgX, and the mixture was stirred for 10 minutes.

【table】

【table】

Then 1.0 g of 4-hydroxy-6-methyl-1,3,3a-tetrazaindene and 20.0 g of 1-phenyl-5-mercaptotetrazole per mole of AgX.
mg and prepared in the usual manner. Furthermore, the following coupler dispersions (1) to (3) are prepared in Table 2 below.
Sample No. 1
~9 was created. α-pivalyl-α-(1-benzyl-2-phenyl-3,5-dioxo-1,2,4-triazolidin-4-yl)-2′-chloro-5′ as yellow coupler per mole of silver halide −[α-(dodecyloxycarbonyl)ethoxycarbonyl]
Add 80g of acetanilide to dibutyl phthalate
Heat and dissolve a mixture of 80 g and 240 ml of ethyl acetate,
A blue-sensitive, high-sensitivity silver halide emulsion was prepared by adding dispersion (1), which was added to an aqueous gelatin solution containing sodium triisopropylnaphthalene sulfonate and emulsified and dispersed in a colloid middle. 1-(2,4,6-trichlorophenyl)-3-{3-(2,4-di-
tert-amylphenoxyacetamido)benzamide}-pyrazolin-5-one 80 g, 1-(2,4,6-trichlorophenyl)-4-(1-naphthylazo)-3- as colored magenta coupler
(2-chloro-5-octadecenylsuccinimidonilino)-5-pyrazolone 2.5 g, 2,5-di-
Add 1.5 g of t-octylhydroquinone, heat and dissolve a mixture of 120 g of tricresyl phosphate and 240 ml of ethyl acetate, add to an aqueous gelatin solution containing sodium triisopropylnaphthalene sulfonate, and emulsify and disperse in a colloid mill. A green-sensitive high-sensitivity emulsion was prepared by adding substance (2). 1-Hydroxy-N-(δ-(2,4-di-t-amylphenoxy)butyl)-2-naphthamide 17 as cyan coupler per mole of silver halide
g, 1-hydroxy-4-[4-(1-hydroxy-δ-acetamido-3,6-disulfo-2-naphthylazo)phenoxy]-N-[δ-(2,4-di-t) as a colored cyan coupler. -Amylphenoxy)butyl]-2-naphthamide disodium salt (4 g) and dodecyl gallate (0.5 g) were added, and a mixture of 20 g of tricresyl phosphate and 60 ml of ethyl acetate was heated and dissolved, and 1.5 g of sodium triisopropylnaphthalenesulfonate was added. 7.5 including
% gelatin aqueous solution and emulsified and dispersed in a colloid mill to prepare a red-sensitive high-sensitivity emulsion. The above nine samples were exposed to light using a wedge, and color development was carried out at 38° C. for 2 minutes using a color developing solution having the composition shown below. After bleaching and fixing, the samples were washed with water, and sensitivity and fog were measured. The results are shown in Table-2.
Note that the sensitivity is expressed as a relative value with the sensitivity of sample No. 1 as 100. Pressure fog was measured by continuously applying a load to a needle with a needle head diameter of 0.1 mm, pulling it across the film surface, developing the film, and measuring the load at which fog occurs as the minimum load (g) at which pressure fog occurs. . For the measurement, the same color development process as used for measuring photographic sensitivity was carried out, and the load at which the color density of the area under load was detected was taken as the minimum load. (Color developer composition) 4-amino-3-methyl-N-ethyl-N-
(β-hydroxyethyl-aniline sulfate
4.75g Anhydrous sodium sulfite 4.25g Hydroxyamine 1/2 sulfate 2.0g Anhydrous potassium carbonate 37.5g Sodium bromide 1.3g Nitrilotriacetic acid trisodium salt (monohydrate)
2.5g Potassium hydroxide 1.0g Add water and adjust to 1 using potassium hydroxide to pH
Adjust to 10.0.

[Table] As is clear from Table 2, the emulsion of the present invention is
Compared to conventional methods and emulsions, this method has the characteristics of a monodisperse emulsion, such as high sensitivity, but it shows a significant improvement in terms of suppressing pressure fog. Example 2 A monodisperse cubic silver iodobromide emulsion with an average grain size of 0.15μ and containing 5 mol% of silver iodide was used as seed grains, and ammonia was mixed with AgX.
As a solvent, the silver iodide content is 8 using the double jet method.
A core/shell type monodisperse silver iodobromide emulsion with an average grain size of 0.5 μm was prepared, having a core with a silver iodide content of 1 mol % and a shell with a silver iodide content of 1 mol %. The pAg during production was maintained at 9.0 until the addition of silver nitrate was completed. Also during manufacturing
PH was kept at 9.0. The average shell thickness of the silver halide grains contained in this emulsion was 0.05 μm, the shape was cubic crystal, and the grain size distribution was 15%. This emulsion was divided into three parts, Rodin ammonium and the above []
After adding the thioether shown by the formula and aging at 50℃, desalting and washing with water by the usual method, pAg was removed at 40℃.
Adjusted to 8.2. These emulsions were mixed into Em-4 to Em-
Set it to 6. Table 3 shows the amounts of rhodanammonium and thioether [] added and the observation results of the particle shape after treatment using an electron microscope.

[Table] Next, 0.40 ml of 0.2% chloroauric acid/tetrahydrate aqueous solution and 0.6 ml of 0.25% sodium thiosulfate/dihydrate aqueous solution were added per mol of AgX.
% rhodan ammonium aqueous solution was added and chemical ripening was performed at 46°C. Next, each emulsion was divided into three parts, and the spectral sensitizing dyes (1) to (3) of Example 1 were added as a methanol solution in an amount of 150 mg per mole of AgX, followed by stirring for 10 minutes. Then 1.0 g of 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene and 1-phenyl-5-mercaptotetrazole per mole of AgX
20.0 mg was added and adjusted in the usual manner. Furthermore, coupler dispersions (1) to (3) shown in Example 1
are added in the combinations shown in Table 4 below,
Samples Nos. 10 to 18 were prepared by adding a common spreading agent and hardening agent, coating and drying. The above nine samples were exposed to light using a wedge, and color development was carried out at 38° C. for 2 minutes using the color developing solution of Example 1. After bleaching and fixing, the samples were washed with water, and sensitivity and fog were measured. The results are shown in Table 4. Note that the sensitivity is expressed as a relative value with the sensitivity of sample No. 10 as 100. The load at which pressure fog occurs was measured in accordance with the method of Example 1.

[Table] As is clear from Table 4, the emulsion of the present invention is
Although it has the characteristic of a monodisperse emulsion of higher sensitivity than conventional emulsions, it shows a significant improvement in the suppression of pressure fog. Example 3 The monodispersed silver iodobromide emulsion prepared in Example 1 was treated as shown in Table 5 below to form Em-7 and Em-8.
I got it.

[Table] Emulsion Em-1 of sample 2 was mixed with Em-7 and Em-8 above.
Instead, samples No. 19 and 20 were prepared as shown in Table 6 below.

[Table] Samples 19 and 20 were evaluated in the same way as samples 1 to 18.
The results are shown in Table-6. Invention sample with roundness in the range of 1/6r to 1/10r
Nos. 5, 8, and 20 are excellent in fog, sensitivity, and pressure fog suppression. Comparative sample No. 19, which has a roundness of 1/4r, is more effective than untreated sample No. 2, but has high fog and a small pressure fog improvement effect. Example 4 Silver halide emulsion (silver bromide 10 mol%, silver chloride 90 mol%) A of Example 1 of JP-A-55-121432
and B were prepared, and the sample was designated as. A pressure fog resistance test was conducted on these samples in the same manner as in Example 1, and the results are shown in Table-
7.

[Table] The silver halide grains used in the samples were highly rounded, and no pressure fog improvement effect was observed.
Samples in which the degree of roundness of the silver halide grains is smaller than that of the silver halide grains of the present invention are found to have an effect of improving pressure fog, but the degree is not satisfactory.

Claims (1)

[Claims] 1 Monodisperse silver iodobromide grains having cubic crystals and/or tetradecahedral crystals whose crystal faces have octagonal and triangular crystal faces whose vertices are slightly rounded by treatment with a silver halide solvent A silver halide emulsion characterized by being an emulsion.