JPH09189978A - Silver halide emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the silver halide emulsion containing flat silver halide grains of novel forms capable of giving superior photographic performance, such as improvement of pressure resistance and restrainment of sensitivity deterioration of the lower layer a laminated coated emulsion layers. SOLUTION: This silver halide emulsion comprises a dispersion medium and silver halide grains containing the polygonal flat silver halide grains amounting to >=50% of the projection areas of the total silver halide grains and having a diameter of >=0.4μm and an aspect ratio of >=2, and the ones amounting to >=30% of the projection areas of the above flat grains having recessed parts from one face to the inside in at least one face of each grain.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a silver halide emulsion comprising a dispersion medium and tabular silver halide grains.

[0002]

2. Description of the Related Art In recent years, silver halide photographic light-sensitive materials have been required to have various performances due to the diversification of their usage and the spread of photographing equipment. One of the major factors that influence the performance of silver halide photographic light-sensitive materials is silver halide grains, and the influence of silver halide grains on photographic performance varies greatly depending on their shape. For example, so-called tabular silver halide grains having a grain diameter considerably larger than the grain thickness are known as silver halide grains which contribute to improvement of image quality and can obtain high sensitivity. This tabular silver halide grain has a large surface area in the same volume as compared with other grain shapes such as a regular hexahedron and can efficiently perform chemical sensitization for enhancing sensitivity (ie, sensitizing dye). It is said that when this is used in a light-sensitive material, high sensitivity can be generally achieved, and small particles can also be achieved, whereby a high quality image can be obtained.

Various emulsions containing tabular silver halide grains have been proposed in which tabular silver halide grains are used in order to improve photographic performance by adding deformation to the shape while taking advantage of the above characteristics. Has been done. For example, U.S. Pat. No. 5,250,408 describes emulsions containing tabular silver halide grains having a hole in the center of the principal plane. When tabular grains having a hole in the center thereof are used in a photographic emulsion layer, the penetration of a developing solution or the like into the emulsion layer is facilitated so that the development can be more easily carried out than ordinary tabular grains. It has been described that it has an advantage that the fixing process can be speeded up.

Further, JP-A-63-316847 describes an emulsion containing tabular silver halide grains in which some of the corners or edges of the grains are lacking. The tabular grains generally have a problem that if they are stored in a solution state of an emulsion, the ridges and corners of the grains are easily dissolved and the sensitivity is likely to be lowered accordingly. In order to solve such problems, the outermost layer is formed into a multi-layered grain having a solubility lower than that of the inner silver halide layer, and the above-mentioned shape is used to store the emulsion in a solution state. It is said that it is possible to secure the property and maintain the high sensitivity when it is used in the photographic emulsion layer.

Further, Japanese Patent Application Laid-Open No. 1-205549 discloses that
Emulsions are described which contain tabular silver halide grains having a curved principal plane. By using the plate-shaped tabular silver halide grains as described above, defects in handling such as pressure fog and pressure desensitization, which are generally considered to occur in tabular grains, are improved, and good pressure characteristics are obtained. It is said that improvements in sensitivity, sharpness, etc. will be achieved at the same time.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a silver halide emulsion containing a tabular silver halide grain having a novel shape capable of imparting excellent photographic performance. In particular, the present invention is to provide a silver halide emulsion exhibiting excellent effects such as improvement of pressure characteristics and suppression of lowering of sensitivity of a lower layer of a multilayer coating emulsion layer.

[0007]

The present inventors have discovered a novel tabular silver halide grain having a concave portion having a concave portion intruding from one side thereof on the surface of the grain, and arrived at the present invention. is there. Since the tabular grains are formed by leaving the substrate grains in a skeleton-like shape while having a recessed portion (recessed portion) having an extremely thin thickness, they are particularly excellent in light transmittance. It also has a relatively strong structure against external pressure. For this reason, when used in a photographic light-sensitive material, this excellent light-transmitting property can suppress a decrease in sensitivity of the lower emulsion layer, which tends to occur due to multi-layer coating, and at the same time, it is also excellent in pressure characteristics. The so-called pressure fog and pressure desensitization can be suppressed. Further, the thinner recessed portion is easily developed, and therefore, rapid processing such as shortening of development time is possible. As described above, the tabular silver halide grain, which is a feature of the present invention, has a shape extremely advantageous in improving photographic performance.

According to the present invention, in a silver halide emulsion comprising silver halide grains and a dispersion medium, silver halide grains corresponding to 50% or more of the projected area of all silver halide grains in the emulsion have a diameter of 0. Polygonal tabular silver halide grains having an aspect ratio of 4 or more and an aspect ratio of 2 or more, and grains corresponding to 30% or more of the total projected area of the polygonal tabular silver halide grains have one side on at least one surface. The silver halide emulsion is characterized in that it has at least one concave portion that has entered inside.

The present invention preferably has the following aspects. (1) The diameter of the tabular silver halide grains is 0.5 to
It is 10 μm (more preferably 1.0 to 5 μm). (2) The aspect ratio of the tabular silver halide grains is
It is 5 to 30 (more preferably 8 to 20). (3) The tabular silver halide grains are silver iodobromide grains. (4) The tabular silver halide grains are silver iodobromide grains, and the silver iodide content is 10 to 40 mol% (more preferably 10 to 20 mol%). (5) Two or more recesses are formed on at least one surface of the tabular silver halide grain. (6) The recesses are formed on both surfaces of the tabular silver halide grain. (7) The recesses are alternately formed on both surfaces of the tabular silver halide grain. (8) The recess has a trapezoidal shape or a triangular shape. (9) The ratio of the area occupied by the concave portions is 30% to 70% with respect to the area of both surfaces of the tabular silver halide grain.
(More preferably 50% to 70%). (10) The surface of the tabular silver halide grain and the recess are separated by steps.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The silver halide emulsion of the present invention comprising tabular silver halide grains and a dispersion medium will be described below. The tabular silver halide grains contained in the emulsion of the present invention (hereinafter sometimes simply referred to as the tabular grains of the present invention) have a projected area of 50 of all silver halide grains in the emulsion.
% Silver halide grains having a diameter of 0.4 μm
The above is a polygonal tabular silver halide grain having an aspect ratio of 2 or more. Here, the diameter means the diameter of a circle having an area equal to the projected area of a particle. The diameter of the tabular grain of the present invention is usually 0.4 to 15 μm, preferably 0.5 to
It is 10 μm, and more preferably 1.0 to 5 μm. Also, the aspect ratio (the ratio of the diameter of a particle to its thickness)
Is usually 2 to 75, preferably 5 to 30, and more preferably 8 to 20. In general, tabular grains have a tabular shape having two parallel faces, and the thickness herein means a distance between the two parallel faces. The thickness of the tabular grains of the present invention is usually 1 μm or less, preferably
0.05 to 1 μm, more preferably 0.1 to 0.5 μm
m. The tabular grains of the present invention contain 50% or more (preferably 70%) of the projected area of all silver halide grains in the emulsion.
As described above, more preferably 80% or more) is a polygonal tabular silver halide grain having the above diameter and aspect ratio. Examples of polygonal tabular silver halide grains include triangles and hexagons.

The tabular grain of the present invention has a concave portion in which 30% or more of the total projected area of the polygonal tabular silver halide grains as described above enters at least one surface from one side to the inside. It has at least one. 1 to 5 show electron micrographs of the structure of the tabular grains of the present invention, respectively. 1 to 3
4 is a photograph of the structure of tabular grains taken from the plane (upper) direction of the tabular grain. As seen in these photographs, the overall shape of the particles is often hexagonal. Then, each of the particles has a recessed part (a part where the light is transmitted and whitened in the photographs of FIGS. 1 to 3 and a recessed part in the photographs of FIGS. 4 and 5) that has entered inside from one side thereof. Have It is preferable that two or more recesses are formed on at least one surface of one particle, and it is preferable that one recess is formed on both surfaces of one particle. 4 and 5
It is preferable that the recesses are alternately formed on both surfaces as seen in FIG. Furthermore, it is preferable that the recess has a trapezoidal shape or a triangular shape. For example, in the case of FIG. 2 described above, the concave portion is formed on each side of the hexagonal particle, and the shape thereof is trapezoidal or triangular.

The ratio of the area occupied by the concave portions is 30% to 70 with respect to the area of both surfaces of the tabular silver halide grain.
% (More preferably 50% to 70%). The thickness of the recess is very thin, usually 0.0
Range of 5 μm to 0.5 μm, preferably 0.05 μm
It is preferably formed in the range of 0.2 μm.
Due to the thin shape of such recesses, good light transmittance is imparted, and when used in a photographic emulsion layer, good development characteristics are achieved in combination with the presence of multiple recesses alternately on both surfaces. can do. The tabular grains of the present invention have a shape in which the substrate (matrix) grains are eroded in the shape of the recessed portion as described above. Therefore, the substrate grains are like beams extending radially from the center thereof. It remains in the shape of (Shadow part of the picture in the figure). Therefore, it has a stronger structure against deformation due to external pressure than ordinary very thin tabular grains. Therefore, it exhibits good pressure characteristics.

As shown in FIG. 4, it is preferable that the surface (substrate particle surface) of the tabular grain of the present invention and the concave portion are separated by steps. Such steps act as places of high reaction activity. Therefore, it can be used not only as an advantageous place for forming a latent image but also as a place where photographic additives such as sensitizing dyes and antifoggants can be selectively adsorbed. As a result, the sensitization efficiency and the effect of suppressing fog can be improved. It is also possible to give a function different from that of the substrate particles by introducing a silver halide having a composition different from that of the substrate particles into this place by utilizing the high reaction activity as described above in the step. is there. For example, when the substrate grains are silver iodobromide, the properties of these grains (for example, development compared to silver iodobromide) can be improved by introducing silver halide such as silver chloride or silver bromide. It is also possible to enhance the developing characteristics by imparting (easy property).

The halogen composition of the tabular grains of the present invention is not particularly limited, but silver iodobromide and silver chloroiodobromide are preferred. Particularly, silver iodobromide is preferable. In this case, the content of silver iodobromide is preferably 10 to 40 mol%, more preferably 10 to 20 mol%.

Next, a method for producing an emulsion containing tabular silver halide grains of the present invention will be described below by using silver iodobromide grains as a typical example thereof. The emulsion containing tabular silver iodobromide grains of the present invention can be produced, for example, by the following steps. The method of producing tabular silver halide grains is already known, and these methods can be used in the present invention in an appropriate combination. (1) To a dispersion medium solution containing silver bromide fine particles as seed crystals, an excess bromide salt solution with respect to silver bromide fine particles is added. The fine silver bromide particles may be prepared in advance according to an ordinary precipitation forming method, or may be prepared from the beginning. That is, it can be prepared by adding an aqueous silver solution and a bromide salt solution to an aqueous dispersion medium solution of a peptizer (generally gelatin) as a dispersion medium introduced into a reaction vessel.
In this case, the preparation method may be a double jet method or a single jet method. The deflocculant is usually adjusted to a concentration of 0.5 to 10% by weight in the dispersion medium solution. The silver bromide fine particles used in the present invention are usually 0.02 μm.
It is preferably 0.1 μm. The size of the particles can be adjusted by the addition rate of the silver solution or the bromide salt solution, the temperature, the kind of the solvent used, and the like.

When an excess bromide salt solution is added to the dispersion medium solution containing the silver bromide fine particles as described above, the fine particles are dissolved,
Recrystallization occurs repeatedly, grain growth is promoted, and tabular grains are formed. The addition amount of the bromide salt solution is 120 mol% or more based on the silver bromide grains, and preferably 120 mol% or more.
˜240 mol%. Reaction temperature is usually 20 ° C
As described above, the temperature is preferably 30 to 85 ° C. The reaction time under stirring is 10 minutes or less, preferably 10 seconds to 5 minutes. No iodide salt is added at the stage of growth of the tabular grains. This is because non-tabular grains are likely to be formed due to the presence of iodine ions.

(2) Next, an iodide salt solution is added to the dispersion medium solution containing the obtained tabular silver bromide grains. The addition amount of the iodide salt solution is 10 mol% or more (more preferably 10 to 20 mol%) with respect to the silver bromide grains. With the addition of this iodide salt solution, silver iodobromide containing a high concentration of iodine is introduced as a compositional component on the surface of grains during the growth process of tabular grains.

(3) After the iodide salt solution of (2) is added, aging (so-called Ostwald ripening) is performed. The aging temperature is almost the same as the grain growth temperature in (1) above. The aging time is at least 30 minutes or more. It is preferably 30 to 60 minutes. With ripening, silver iodobromide adheres to the surface of the grains, forming triangular or hexagonal tabular grains. And as it matures further,
This time, the crystal layer of silver iodobromide adhering to the surface is melted, and finally tabular silver iodobromide grains having concave portions (depressions) are formed on the surface.

(4) After the tabular silver iodobromide grains are formed as described above, desalting and washing with water are carried out according to the usual flocculation method.
H and pAg can be adjusted to prepare an emulsion containing tabular silver iodobromide grains according to the present invention. The tabular grains of the present invention prepared by the above steps are present in the emulsion as grains corresponding to 30% or more (preferably 50% or more, more preferably 70% or more) of the total projected area. Is preferred.

As a method for preparing the tabular grains of the present invention, in the above step (1), 10 mol% or more (preferably, preferably 10 mol% or more of silver bromide grains) is added to a dispersion medium solution containing fine silver bromide grains in advance. Silver iodide fine particles (10 to 20 mol%) can be present. In the form of fine silver iodide grains, the release of iodine is relatively suppressed even when a bromide salt solution is introduced, so that it does not hinder the production of tabular silver bromide grains. The grain size of the silver iodide fine grains is not particularly limited, but it is preferable that it is substantially the same as the grain size of the silver bromide fine grains. When silver iodide fine grains are thus introduced, the ripening time must be at least 90 minutes or longer. The range is preferably 90 to 150 minutes. Further, by using this method, the step (2) can be omitted in the above-mentioned preparation step.

After addition of the excess bromide salt solution of the above (1), the bromide salt solution is introduced together with silver iodide fine particles in an amount of 10 mol% or more (preferably 10 to 20 mol%) based on the silver bromide grains. You can also do it. By utilizing this method, the aging time needs to be at least 90 minutes or more as in the above. The range is preferably 90 to 150 minutes. Further, in the above-mentioned preparation step, the step (2) can be omitted, which is the same as above.

When forming the tabular silver halide grains of the present invention, a silver halide solvent can be used to control the growth of the grains. Examples of these include ammonia, rodancali, rodanammon, and thioether compounds (for example, U.S. Pat.
Nos. 271157, 357462, and 37041
No. 30, No. 4297439, No. 4276374
No., JP-B-58-30571, JP-A-60-1367
No. 36, especially 3,6-dithia-
1,8-octanediol, JP-A-2-118566, etc.), tetra-substituted thiourea compounds (for example,
No. 11892, compounds described in U.S. Pat. No. 4,221,863, particularly tetramethylthiourea) and thione compounds (for example, JP-A-53-144319 and JP-A-53-82).
No. 408, No. 55-77737, Japanese Patent Publication No. 60-113
No. 4), an amine compound (for example,
No. 100717), selenoether compounds (for example, US Pat. No. 4,781,2013), and sulfites. Of these, thioether compounds, tetrasubstituted thiourea compounds, and thione compounds are preferred. The amount of the silver halide solvent to be used is generally about 10 ^-5 to 10 ^-2 mol per mol of silver halide.

In the process of silver halide grain formation or physical ripening, ruthenium salt, zinc salt, chromium salt, iridium salt or its complex salt, rhodium salt or its complex salt, iron salt or iron complex salt may be present together. Particularly, iridium salts, iron salts, and rhodium salts are preferable.

The silver halide emulsion of the present invention is usually chemically sensitized before use. In chemical sensitization, conventional sulfur sensitization, selenium sensitization, tellurium sensitization, reduction sensitization, and noble metal sensitization are preferably used alone or in combination. In sulfur sensitization, an unstable sulfur compound is used, and P.
Grafkides, Chimie et Physique Photographique (P
aul Momtel, 1987, 5th edition), Research Dis
Unstable sulfur compounds described in Closure magazine volume 307, 307105, etc. can be used. Specifically, thiosulfates (for example, hypo), thioureas (for example, diphenylthiourea, triethylthiourea, N-ethyl-N ′-(4-methyl-2-thiazolyl) thiourea, carboxymethyltrimethylthio. Urea), thioamides (for example, thioacetamide), rhodanines (for example, diethyl rhodanine, 5-benzylidene-N-ethyl rhodanine), phosphine sulfides (for example, trimethylphosphine sulfide), thiohydantoins, 4, -Oxo-oxazolidine-2-thiones, disulfides or polysulfides (eg,
Known sulfur compounds such as dimorpholine disulfide, cystine, lenthionine) and polythionate, and active gelatin can also be used.

In the selenium sensitization, as unstable selenium compounds, Japanese Examined Patent Publication Nos. 43-13489 and 44-1 are used.
5748, JP-A-4-25832, JP-A-4-1093
No. 40, No. 4-271341, No. 5-40324,
Nos. 5-11385, 6-51415, 6-17
No. 5258, No. 6-180478, No. 6-20818
No. 6, No. 6-208184, No. 6-317867,
7-92599, 7-98483, Japanese Patent Application No. 5-
A selenium compound described in each gazette such as 286916 or the specification can be used. Specifically, colloidal metal selenium, selenoureas (for example,
N, N-dimethylselenourea, trifluoromethylcarbonyl-trimethylselenourea, acetyl-trimethylselenourea), selenoamides (eg, selenoamide, N, N-diethylphenylselenoamide), phosphine selenides (eg, tri Phenylphosphine selenide, pentafluorophenyl-diphenylphosphine selenide), selenophosphates (eg,
Examples thereof include tri-p-tolylselenophosphate, tri-n-butylselenophosphate), selenoketones (for example, selenobenzophenone), isoselenocyanates, selenocarboxylic acids, selenoesters, and diacylselenides. Further, non-labile selenium compounds described in JP-B-46-4553 and JP-B-52-34492, such as selenous acid,
Potassium selenocyanate, selenazoles, selenides and the like can also be used.

In tellurium sensitization, an unstable tellurium compound is used, and JP-A-4-224595 and JP-A-4-2713 are used.
No. 41, No. 4-33043, No. 5-303157,
6-27573, 6-175258, and 6-1
No. 80478, No. 6-208186, No. 6-2081
Unstable tellurium compounds described in Japanese Unexamined Patent Publication Nos. 84 and 6-31767, and Japanese Patent Application No. 5-286916 can be used. Specifically, phosphine tellurides (e.g., butyl-diisopropylphosphine telluride, tributylphosphine telluride, tributoxyphosphine telluride, ethoxy-diphenylphosphine telluride), diacyl (di) tellurides ( For example, bis (diphenylcarbamoyl) ditelluride, bis (N-phenyl-N-methylcarbamoyl) ditelluride, bis (N-phenyl-N-methylcarbamoyl) telluride, bis (N-phenyl-N-benzylcarbamoyl) telluride, bis ( (Ethoxycarbonyl) telluride), telluroureas (eg, N, N'-dimethylethylene tellurourea, N, N'-diphenylethylene tellurourea), telluramides, telluroesters, and the like.

In sensitizing precious metals, P. Grafukides,
Chimie et Physique Photographique (Paul Momtel, 1987, 5th edition), Research Disclosure 3
Noble metal salts such as gold, platinum, palladium and iridium described in Vol. 07, No. 307105 and the like can be used, and gold sensitization is particularly preferable. Specifically, in addition to chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, and gold selenide, U.S. Pat. Nos. 2,642,361, 5,049,484 and 5,539
No. 049485, No. 5169751, No. 525245
No. 5, or a gold compound described in Belgian Patent No. 691857 can also be used.

Regarding reduction sensitization, P. Grafukides, Ch.
imie et Physique Photographique (Paul Momtel,
1987, 5th edition), Research Disclosure 307
No. 307105, Japanese Patent Application No. 7-78685, and the like.
Specifically, aminoiminomethanesulfinic acid (alias,
Thiourea dioxide, borane compounds (eg, dimethylamine borane), hydrazine compounds (eg, hydrazine, p-tolylhydrazine), polyamine compounds (eg, diethylenetriamine, triethylenetetramine), stannous chloride, silane compounds, reductones (For example, ascorbic acid), sodium sulfite, an aldehyde compound, hydrogen gas, or the like may be used. Also, high pH
The reduction sensitization may be performed in an atmosphere having an excess of silver ions (so-called silver ripening). In particular, reduction sensitization is preferably performed during the formation of silver halide grains. In the present invention, it is preferable to use the gold sensitization method in combination with another sensitization method.

The silver halide emulsion of the present invention is preferably spectrally sensitized with methine dyes and the like.
Dyes used include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes, and hemioxonol dyes. Particularly useful dyes are those belonging to the cyanine dyes, merocyanine dyes, and complex merocyanine dyes. Any of the nuclei usually used for cyanine dyes as basic heterocyclic nuclei can be applied to these dyes. That is, the pyrroline nucleus is an oxazoline nucleus, a thiazoline nucleus, a pyrrole nucleus,
Oxazole nuclei, thiazole nuclei, selenazole nuclei, imidazole nuclei, tetrazole nuclei, pyridine nuclei, etc .; nuclei in which alicyclic hydrocarbon rings are fused to these nuclei: and nuclei in which aromatic hydrocarbon rings are fused to these nuclei, ie , Indolenine nucleus, benzindolenine nucleus, indole nucleus, benzoxadol nucleus, naphthoxazole nucleus, benzothiazole nucleus, naphthothiazole nucleus, benzoselenazole nucleus, benzimidazole nucleus, quinoline nucleus and the like can be applied. These nuclei may have a substituent on a carbon atom.

In the merocyanine dye or the complex merocyanine dye, as a nucleus having a ketomethylene structure, for example, a pyrazolin-5-one nucleus, a thiohydantoin nucleus, a 2-thiooxazolidin-2,4-dione nucleus, a thiazolidine-
A 5- or 6-membered heterocyclic nucleus of a 2,4-dione nucleus, a rhodanine nucleus and a thiobarbituric acid nucleus can be applied.

These sensitizing dyes may be used alone, or a combination thereof may be used. Combinations of sensitizing dyes are often used, especially for supersensitization. Along with the sensitizing dye, the emulsion may contain a dye which does not itself have a spectral sensitizing effect or a substance which does not substantially absorb visible light and exhibits supersensitization. For example, a substituted aminostilbenzene compound having a nitrogen-containing heterocyclic nucleus group (for example, US Pat. Nos. 2,933,390 and 36)
No. 35721), formaldehyde condensates of aromatic organic acids (for example, those described in US Pat. No. 3,743,510), cadmium salts, azaindene compounds and the like. U.S. Pat. Nos. 3,615,613 and 361
The combinations described in 5641, 3617295 and 3635721 are particularly useful.

The silver halide emulsion of the present invention can be used in conventionally known photographic light-sensitive materials. For example, black-and-white silver halide photographic light-sensitive material (X-ray light-sensitive material, printing light-sensitive material, negative film, microfilm, direct positive light-sensitive material, ultrafine particle plate light-sensitive material, etc.),
It can be used as a color photographic light-sensitive material (color negative film, reversal film, direct positive color light-sensitive material, silver dye bleaching method photograph, etc.), a diffusion transfer light-sensitive material, a photothermographic material.

Next, a silver halide photographic light-sensitive material (sometimes referred to simply as a light-sensitive material) using the silver halide emulsion of the present invention will be described. The silver halide photographic light-sensitive material has at least one emulsion layer (photographic light-sensitive layer) containing the silver halide emulsion of the present invention on a support. Ordinary photosensitive materials are further provided with a hydrophilic colloid layer such as an intermediate layer, a back layer and a protective layer in addition to the emulsion layer.

As the binder or protective colloid that can be used in the emulsion layer or intermediate layer of the photographic light-sensitive material, it is advantageous to use gelatin, but other hydrophilic colloids can also be used. For example, gelatin derivatives, graft polymers of gelatin and other polymers, albumin,
Proteins such as casein; cellulose derivatives such as hydroxyethylcellulose, carboxymethylcellulose and cellulose sulfates; sugar derivatives such as sodium alginate and starch derivatives; polyvinyl alcohol, polyvinyl alcohol partial acetal, poly-N-vinylpyrrolidone, polyacrylic acid; Various synthetic hydrophilic polymer substances such as polymethacrylic acid, polyacrylamide, polyvinylimidazole, and polyvinylpyrazole, such as a single or copolymer, can be used.

In the photographic light-sensitive material, any hydrophilic colloid layer constituting the emulsion layer or the back layer may contain an inorganic or organic hardener. Examples of these include chromium salts, aldehyde salts (eg, formaldehyde, glyoxal, glutaraldehyde), and N-methylol-based compounds (eg, dimethylol urea). Active halogen compounds (eg, 2,4-dichloro-6-hydroxy-1,3,5-triazine and its sodium salt) and active vinyl compounds (eg,
1,3-bisvinylsulfonyl-2-propanol,
1,2-bis (vinylsulfonylacetamido) ethane, bis (vinylsulfonylmethyl) ether or vinyl polymer having a vinylsulfonyl group in the side chain
Is preferred because it rapidly cures a hydrophilic colloid such as gelatin and gives stable photographic properties. N-carbamoylpyridinium salts (for example, (1-morpholinocarbonyl-3
-Pyridinio) methanesulfonate) and haloamidium salts (eg, 1- (1-chloro-1-pyridinomethylene) pyrrolidinium-2-naphthalenesulfonate) also cure quickly and are excellent.

The silver halide emulsion of the present invention may contain various compounds for the purpose of preventing fog during the production process of the light-sensitive material, during storage or during photographic processing, or stabilizing photographic performance. it can. That is, azoles (for example, benzothiazolium salts, nitroimidazoles, nitrobenzimidazoles, chlorobenzimidazoles, bromobenzimidazoles, mercaptothiazoles, mercaptobenzthiazoles, mercaptobenzimidazoles, mercaptothiadiazoles, amino Triazoles, benzotriazoles, nitrobenzotriazoles, mercaptotetrazoles (especially 1-phenyl-5-mercaptotetrazoles)
Etc.); mercaptopyrimidines; mercaptotriazines; thioketo compounds (eg, oxadrithione);
Azaindenes (eg, triazaindenes, tetraazaindenes (particularly 4-hydroxy-6-methyl (1,3,3a, 7) tetraazaindene), pentaazaindenes); benzenethiosulfonic acid, benzenesulfine Acids and many compounds known as antifoggants or stabilizers such as benzene sulfonic acid amides can be added.

The photographic light-sensitive material may contain one or more surfactants for various purposes such as coating aid, antistatic property, slipperiness improvement, emulsion dispersion, adhesion prevention and photographic property improvement (for example, development acceleration, contrast enhancement, sensitization). May be included.

The photographic light-sensitive material is used as a filter dye.
Alternatively, a water-soluble dye may be contained in the hydrophilic colloid layer for the purpose of preventing irradiation or halation and other various purposes. Preferred examples of such dyes include oxonol dyes, hemioxonol dyes, styryl dyes, merocyanine dyes, anthraquinone dyes, and azo dyes. In addition, cyanine dyes, azomethine dyes, triarylmethane dyes, and phthalocyanine dyes are also useful. The oil-soluble dye may be emulsified by an oil-in-water dispersion method and added to the hydrophilic colloid layer.

The photographic light-sensitive material has at least 2 on the support.
It can be constructed as a multilayer multicolor photographic material having two different spectral sensitivities. The multilayer natural color photographic material usually has at least one red-sensitive emulsion layer, one green-sensitive emulsion layer and one blue-sensitive emulsion layer on a support. The arrangement order of these layers can be arbitrarily selected as needed. The preferred layer arrangement is from the support side in the order of red sensitivity, green sensitivity and blue sensitivity, blue sensitivity, green sensitivity and red sensitivity or blue sensitivity, red sensitivity and green sensitivity. In addition, any emulsion layer having the same color sensitivity may be composed of two or more emulsion layers having different sensitivities to improve the reaching sensitivity, or a three-layer constitution may be used to further improve the graininess. Further, a non-photosensitive layer may be present between two or more emulsion layers having the same color sensitivity. An emulsion layer having a different color sensitivity may be inserted between emulsion layers having the same color sensitivity. A reflective layer of fine grain silver halide or the like may be provided below the high-sensitivity layer, particularly the high-sensitivity blue-sensitive layer, to improve the sensitivity.

The additives used in the silver halide emulsion of the present invention are Research Disclosure No. 1764
3, the same No. 18716 and the same No. 307105, and the relevant portions are described below. ──────────────────────────────────── Additive type RD17643 RD18716 RD307105 [December 1978] [ November 1979] [November 1989] ───────────────────────────────────── 1. Chemical sensitizer page 23 page 648 right column page 866 2. Sensitivity enhancer Page 648, right column 3. Spectral sensitizer, pages 23 to 24, page 648, right column to pages 866 to 868, supersensitizer, page 649, right column 4. Whitening agent Page 24 Page 647 Right column Page 868 5. 5. Antifoggant page 24 to 25 page 649 right column page 868 to 870 Stabilizer 6. Light absorber page 25-26 page 649 right column-page 873 filter dye, page 650 left column UV absorber 7. Stain inhibitor 25 pages, right column, 650 pages, left to right column, 872 pages Dye image stabilizer page 25 page 650 page left column page 872 9. Hardener page 26 page 651 left column 874-875 10. Binder page 26 page 651 left column 873-874 11. Plasticizers and lubricants page 27 650 page right column page 876 12. Coating aid, pages 26 to 27, page 650, right column, pages 875 to 876 Surfactant 13. Anti-stuck agent 27 pages 650 right column 876-877 14. Matting agent 878-879 ───────────────────────────── ───────

Regarding other techniques and inorganic and organic materials which can be used for a photographic light-sensitive material using the silver halide emulsion of the present invention, European Patent No. 436938A2
See the following section of the issue and the patents referenced below. ──────────────────────────────────── 1. 1. Layer structure: page 146, line 34 to page 147, line 25 2. Yellow coupler: page 137, line 35 to page 146, line 33, page 149, lines 21 to 23 3. Magenta coupler: page 149, lines 24 to 28; EP 421,453A1, page 3, line 5 to page 25, line 55 4. Cyan coupler: page 149, lines 29 to 33; EP 432,804 A2, page 3, line 28 to page 40, line 2 5. Polymer coupler: page 149, lines 34 to 38; EP 435, 334A2, page 113, line 39 to page 123, line 37. 6. Colored coupler: page 53, line 42 to page 137, line 34, page 149, line 39 to line 45 Other functional couplers: page 7, line 1 to page 53, line 41, page 149, line 46 to page 150, line 3; EP 435, 334A2, page 3, line 1 to Page 29, line 50 8. 8. Antiseptic / antifungal material: page 150, lines 25-28 Formalin Scavenger: page 149, lines 15 to 17 10. Other additives: page 153, lines 38 to 47; EP 421, 453A1, page 75, lines 21 to 84. Line 56, page 27, line 40 to page 37, line 40 11. Dispersion method: page 150, lines 4 to 24 12. Support: page 150, lines 32 to 34 13. Membrane Thickness / Film physical properties: page 150, lines 35 to 49 14. Color development step: page 150, lines 50 to 151, line 47 15. Desilvering step: page 151, lines 48 to 152 Line 53 16. Automatic developing machine: page 152, line 54 to page 153, line 2 17. Washing and stabilizing step: page 153, lines 3 to 37 ───────────────────

[0042]

The present invention will be described more specifically with reference to the following examples.

[Example 1] (Preparation of tabular silver iodobromide grains) Silver bromide fine grains were prepared by stirring an 8 wt% gelatin aqueous solution containing silver bromide fine grains (average grain size 50 nm) kept at 70 ° C. On the other hand, a 120 mol% potassium bromide aqueous solution was added and stirring was continued for 2 minutes. Then, a 20 mol% potassium iodide aqueous solution was added to the silver bromide fine particles, and stirring was continued for 45 minutes. After grain formation, desalting and washing with conventional flocculation method, gelatin and water were added to adjust pH to 6.0, pA
The g was adjusted to 8.8. Through the above steps, an emulsion containing tabular silver iodobromide grains according to the present invention was prepared. It was confirmed that the obtained silver halide grains had substantially the same shape as that shown in the photographs of FIGS. The obtained silver halide grains were tabular silver iodobromide grains having 50% of the projected area of all grains in the emulsion, and the diameter was 5 μm and the aspect ratio was 25. Further, particles corresponding to 50% of the projected area of the particles had at least one recess.

Example 2 (Preparation of tabular silver iodobromide grains) Fine silver bromide particles (average grain size 50 nm) kept at 70 ° C. and 20 mol% iodide based on the fine silver bromide grains. Fine silver particles (average particle size 5
(0 nm) containing 8 wt% gelatin aqueous solution was stirred, and 120 mol% potassium bromide aqueous solution was added to the silver halide contained in the solution, and stirring was continued for 120 minutes. After grain formation, desalting and washing with conventional flocculation method, gelatin and water were added to adjust pH to 6.0, pA
The g was adjusted to 8.8. Through the above steps, an emulsion containing tabular silver iodobromide grains according to the present invention was prepared. It was confirmed that the obtained silver halide grains had substantially the same shape as that shown in the photographs of FIGS. The obtained silver halide grains were tabular silver iodobromide grains (silver iodide content: 20 mol%) corresponding to 75% of the projected area of all grains in the emulsion and had a diameter of 10 μm.
m and the aspect ratio was 50. Further, particles corresponding to 60% of the projected area of the particles had at least one recess.

[Example 3] (Preparation of tabular silver iodobromide grains) Silver bromide fine grains were prepared by stirring an 8 wt% gelatin aqueous solution containing silver bromide fine grains (average grain size 50 nm) kept at 70 ° C. On the other hand, a 120 mol% potassium bromide aqueous solution was added and stirring was continued for 2 minutes. Then, each is 40 mol% with respect to silver bromide fine
The above silver iodide fine particles and a potassium bromide aqueous solution were added, and stirring was continued for 120 minutes. After the particles were formed, desalting and washing with water were performed by a conventional flocculation method, and gelatin and water were added to adjust the pH to 6.0 and the pAg to 8.8. Through the above steps, an emulsion containing tabular silver iodobromide grains according to the present invention was prepared. The silver halide grains obtained are shown in FIG.
~ It was confirmed that it had a shape substantially similar to the shape shown in the photograph of Fig. 3. The obtained silver halide grains were tabular silver iodobromide grains (silver iodide content: 20 mol%) corresponding to 50% of the projected area of all grains in the emulsion, and the diameter thereof was 5 μm. The aspect ratio was 25.
Further, particles corresponding to 50% of the projected area of the particles had at least one recess.

Comparative Example 1 (Preparation of tabular silver iodobromide grains) Gelatin 8 g and KBr6
1 liter of an aqueous solution containing g was kept at 40 ° C. under stirring. Aqueous silver nitrate solution (AgNO _3: 0.3 g) and potassium bromide aqueous solution: were added simultaneously over (KBr 0.2 g) for 3 minutes. After the addition is complete, raise the temperature of the solution to 75 ° C,
Mixed aqueous solution of potassium bromide and potassium iodide (KBr:
100 g, KI: 15 g) and a 10% aqueous solution of silver nitrate,
It was added simultaneously over 30 minutes while adjusting the silver electrode potential of the reaction tank to −5 mV. After the particles were formed, desalting and washing with water were performed by a conventional flocculation method, and gelatin and water were added to adjust the pH to 6.0 and the pAg to 8.8. Through the above steps, an emulsion containing ordinary tabular silver iodobromide grains was prepared. The obtained silver halide grains had tabular silver iodobromide grains corresponding to 90% of the projected area of all grains in the emulsion (silver iodide content: 10 mol%) and had a diameter of 2 μm. The aspect ratio was 10.

[Evaluation as a photographic light-sensitive material using a silver halide emulsion] Each emulsion obtained was chemically sensitized and then spectrally sensitized as follows. After the temperature of each emulsion was raised to 60 ° C., potassium thiocyanate was added, and 2 minutes later, a sulfur compound was added, followed by ripening for 60 minutes. After the completion of the chemical ripening, the mixture was further divided into 2 minutes, and anhydro-5-chloro-
5′-Phenyl-9-ethyl-3,3′-di (3-sulfopropyl) benzoxacarbocyanine hydroxide sodium salt (670 mg / mol AgX) was added. Then, a photographic light-sensitive material was prepared using these emulsions, and (1) pressure characteristics (pressure desensitization, pressure fog) and (2) light transmittance of each emulsion were examined and evaluated by the following methods.

(1) Evaluation of pressure characteristics (Preparation of photographic light-sensitive material) The following components were added to each of the obtained emulsions, and the emulsion (coating solution for emulsion layer) was used as a gelatin protective layer containing polymethylmethacrylate particles. The emulsion layer and the protective layer were formed by coating the triacetyl cellulose film support having an undercoat layer together with the coating solution by the simultaneous extrusion method to prepare respective light-sensitive materials corresponding to Examples and Comparative Examples. Magenta coupler; 3- {3- [2- (2,4-di-t
ert-amylphenoxy) butyrylamino] benzoylamino} -1- (2,4,6-trichlorophenyl)
Pyrazolone-5-one oil; tricresyl phosphate stabilizer; 4-hydroxy-6-methyl-1,3,3a,
7-Tetrazaindene Coating aid; Sodium dodecylbenzenesulfonate Hardener; 1,2-Bis (vinylsulfonylacetylamino) ethane Preservative; Phenoxyethanol

A pin was pressed against the obtained sample (photosensitive material) from above the protective layer (pressure: 6 kg / mm).
² ), scratched. Then, exposure and development were carried out according to a conventional method, and the pressure characteristics were examined. The development was performed according to the following development processing. As a result, the photographic light-sensitive material using the emulsion containing tabular silver iodobromide grains according to the present invention was pressure-sensitized as compared with the photographic light-sensitive material using the conventional emulsion containing tabular silver iodobromide grains. It was confirmed that there was almost no pressure fog and good pressure characteristics were exhibited.

(Treatment method) Step Treatment time Treatment temperature Color development phenomenon 2 minutes 15 seconds 38 ° C Bleach 6 minutes 30 seconds 38 ° C Water wash 2 minutes 10 seconds 24 ° C settling 4 minutes 20 seconds 38 ° C water wash (1) 1 minute 05 seconds 24 ℃ Washing with water (2) 1 minute 00 seconds 24 ℃ Stability 1 minute 05 seconds 38 ℃ Dry 4 minutes 20 seconds 55 ℃

Next, the composition of the treatment liquid is shown. (Color developer) (Unit: g) Diethylenetriaminepentaacetic acid 1.0 1-Hydroxyethylidene-1,1-diphosphonic acid 3.0 Sodium sulfite 4.0 Potassium carbonate 30.0 Potassium bromide 1.4 Potassium iodide 1. 5 mg hydroxylamine sulfate 2.4 4- (N-ethyl-N-β-hydroxyethylamino) -2-methylaniline sulfate 4.5 water was added to 1.0 liter pH 10.5

(Bleaching Solution) (Unit: g) Ethylenediaminetetraacetic acid sodium ferric trihydrate 100.0 Ethylenediaminetetraacetic acid disodium chloride 10.0 Ammonium bromide 140.0 Ammonium nitrate 30.0 Ammonia water (27%) 6 Add 0.5 ml water 1.0 liter pH 6.0

(Fixer) (Unit: g) Ethylenediaminetetraacetic acid secondary sodium salt 0.5 Sodium sulfite 7.0 Sodium bisulfite 5.0 Ammonium thiosulfate aqueous solution (70%) 170 ml Water added 1.0 liter pH 6.7

(Fixer) (Unit: g) Formalin (37%) 2.0 ml Polyoxyethylene-p-monononylphenyl ether 0.3 (Average degree of polymerization 10) Ethylenediaminetetraacetic acid disodium salt 0.05 Water In addition 1.0 liter pH 5.0-8.0

(2) Evaluation of Light Transmittance (Preparation of Photosensitive Material) In the same manner as above except that the emulsion obtained in Comparative Example 1 was coated on a triacetyl cellulose film support having an undercoat layer. A light-sensitive material was prepared. That is, after forming an emulsion layer (first layer) using the emulsion obtained in Comparative Example 1, each emulsion was further coated on this emulsion layer by the same coextrusion method as described above for coating an emulsion and a gelatin protective layer. The solution was applied to form an emulsion layer (second layer) and a protective layer, respectively, to prepare respective light-sensitive materials corresponding to each Example and Comparative Example.

The obtained sample (photosensitive material) was exposed by a conventional method and then developed in the same manner as above. The light transmittance was examined by measuring and comparing the concentrations of the treated samples. As a result, the photographic light-sensitive material in which the emulsion containing tabular silver iodobromide grains according to the present invention was used in the emulsion layer (second layer) on the exposed side was the emulsion containing conventional tabular silver iodobromide grains. It was confirmed that the decrease in sensitivity was less than that of the photographic light-sensitive material used for the emulsion layer on the exposure side. From this, it is clear that by using the emulsion containing tabular silver iodobromide grains according to the present invention, in a photographic light-sensitive material having an emulsion layer having a multi-layer structure, it is possible to suppress the lowering of the sensitivity of the emulsion layer as the lower layer. Became.

[0057]

EFFECTS OF THE INVENTION The polygonal tabular silver halide grain of the present invention has a very thin thickness of recessed portion (indentation) entering from one side thereof. Therefore, it is particularly excellent in light transmittance. Further, since the substrate grains excluding the concave portions are left in a beam-like shape radially from the center of the grain, the tabular grains of the present invention have a structure relatively strong against deformation due to external pressure. doing. Therefore, when the tabular grains of the present invention are used in a photographic light-sensitive material, due to this excellent light-transmitting property, it is possible to suppress the lowering of sensitivity of the lower emulsion layer which is likely to occur due to multilayer coating, and at the same time, pressure fog Also, pressure desensitization can be suppressed. Since it has a thinner concave portion, it is easy to develop in this portion, and the processing speed can be increased. Further, the step formed between the surface of the tabular grain and the concave portion acts as a place where the reaction activity is high. Therefore, in this portion, formation of a latent image or adsorption of a photographic additive such as a sensitizing dye is easily performed, and sensitization can be efficiently performed.
From these facts, the polygonal tabular silver halide grain of the present invention has an excellent shape for improving photographic performance.

[Brief description of the drawings]

FIG. 1 is an electron micrograph (taken from the plane direction) showing an example of the structure of a tabular silver halide grain of the present invention.

FIG. 2 is an electron micrograph (taken from the plane direction) showing another example of the structure of the tabular silver halide grain of the present invention.

FIG. 3 is an electron micrograph (taken from the plane direction) showing another example of the structure of the tabular silver halide grain of the present invention.

FIG. 4 is an electron micrograph showing an example of the structure of tabular silver halide grains of the present invention.

FIG. 5 is an electron micrograph showing another example of the structure of the tabular silver halide grain of the present invention.

[Procedure amendment]

[Submission date] March 8, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

Next, a method for producing an emulsion containing tabular silver halide grains of the present invention will be described below by using silver iodobromide grains as a typical example thereof. The emulsion containing tabular silver iodobromide grains of the present invention can be produced, for example, by the following steps. The method of producing tabular silver halide grains is already known, and these methods can be used in the present invention in an appropriate combination. (1) To a dispersion medium solution containing silver bromide fine particles as seed crystals, an excess bromide salt solution with respect to silver bromide fine particles is added. The fine silver bromide particles may be prepared in advance according to an ordinary precipitation forming method, or may be prepared from the beginning. That is, it can be prepared by adding an aqueous silver solution and a bromide salt solution to an aqueous dispersion medium solution of a peptizer (generally gelatin) as a dispersion medium guided in a reaction vessel.
In this case, the preparation method may be a double jet method or a single jet method. The deflocculant is usually adjusted to a concentration of 0.5 to 10% by weight in the dispersion medium solution. The silver bromide fine particles used in the present invention are usually 0.02 μm.
Those of ~ 0.1μm is preferable. The size of the particles can be adjusted by the addition rate of the silver solution or the bromide salt solution, the temperature, the kind of the solvent used, and the like.

Claims (8)

[Claims] 1. A silver halide emulsion comprising silver halide grains and a dispersion medium, wherein the silver halide grains corresponding to 50% or more of the projected area of all the silver halide grains in the emulsion have a diameter of 0.4 μm or more. , And polygonal tabular silver halide grains having an aspect ratio of 2 or more, and the grains corresponding to 30% or more of the total projected area of the polygonal tabular silver halide grains are on at least one surface from one side to the inside. A silver halide emulsion characterized in that it has at least one recessed portion. 2. The silver halide emulsion according to claim 1, wherein the tabular silver halide grains are silver iodobromide grains. 3. The silver halide emulsion according to claim 1, wherein two or more recesses are formed on at least one surface of the tabular silver halide grains. 4. The silver halide emulsion according to claim 1, wherein the concave portions are formed on both surfaces of the tabular silver halide grain. 5. The silver halide emulsion according to claim 1, wherein recesses are formed alternately on both surfaces of the tabular silver halide grains. 6. The silver halide emulsion according to claim 1, wherein the recess has a trapezoidal shape or a triangular shape. 7. The ratio of the area occupied by the recesses to the area of both surfaces of the tabular silver halide grains is 30% to 7%.
The silver halide emulsion according to claim 1, which is 0%. 8. The silver halide emulsion according to claim 1, wherein the surface of the tabular silver halide grain and the recess are separated by steps.