JPS6239847A - Direct positive silver halide photographic sensitive material - Google Patents

Abstract

PURPOSE:To obtain a clear image having sufficiently high maximum density and sufficiently low minimum density at a high developing speed by using specified internal latent image type silver halide (AgX) particles in a sensitive material giving a direct positive image by fogging after imagewise exposure. CONSTITUTION:When one or more AgX emulsion layers, contg. internal latent image type AgX particles having unfogged surfaces are formed to obtain a photographic sensitive material giving a direct positive image by imagewise exposure and fogging followed by surface development and/or surface development under fogging, each of the internal latent image type AgX particles is composed of a chemically sensitized or metallic ion doped core and a multilayered shell consisting of at least two layers and covering the core, and the silver chloride content in the outermost layer of the shell is made lower than that in a layer adjacent to the outermost layer. A fine positive image having high maximum density, low minimum density and high sensitivity is obtd. by using an internal latent image type AgX emulsion contg. such AgX particles. The fine image is rapidly obtd. even by bleach fixing immediately after development.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a direct positive silver halide photographic light-sensitive material, and more specifically, after image exposure, fogging treatment (for example, full-surface exposure or removal of a fogging agent) is performed. The present invention relates to a photographic light-sensitive material having an internal latent image type silver halide emulsion layer from which a positive image can be directly obtained by surface development processing in the presence of the present invention.

[Prior Art] Conventionally known methods for obtaining direct positive images are mainly divided into two types. One type uses a silver halide emulsion that has fog nuclei in advance, and destroys the fog nuclei or latent image in the exposed area using solarization or the Burschel effect.
A positive image is obtained after development. The other type uses an internal latent image type silver halide emulsion that has not been fogged in advance, performs fogging treatment (development nucleation treatment) after image exposure, and then performs surface development, or performs fogging treatment after image exposure. A positive image can be obtained by performing surface development while performing (development nucleation treatment).

The above fogging process (development nucleation process) may be performed by exposing the entire surface to light, chemically using a fogging agent, or using a strong developer, and further heat treatment. etc. may also be used.

Of the above two methods for forming a positive image, the latter type of method generally has higher sensitivity than the former type of method, and is suitable for applications requiring high sensitivity.

Various techniques are known in this technical field. For example, U.S. Pat. No. 2,592.25'0,
No. 2,488,957, No. 2,497,875, No. 2,588.982, No. 3,781,288, No. 3
, 781,278, 3.798,577 and British Patent No. 1,151,383 are known.

[Problems to be Solved by the Invention] Although it is possible to produce photographic materials that form positive images by using these known techniques, it is more difficult to apply these photographic materials to various photographic fields. Further improvement of photographic performance is desired.

・For example, U.S. Patent No. 3,781,287 and U.S. Patent No. 3,2
Higher sensitivity can be obtained by chemically sensitizing the interior of silver halide grains or by using a core/shell type emulsion doped with polyvalent metal ions, as disclosed in No. 08,313. However, this type of emulsion has the disadvantage of low image density. Also US Patent 3,78
No. 1,278 discloses that the surface of silver halide grains is subjected to a certain degree of chemical ripening treatment in order to improve the above-mentioned drawback of low image density, but the speed at which the image appears is sufficiently high. However, there is a need for an internal latent image type silver halide emulsion that is more suitable for rapid processing.

Furthermore, when using a silver halide emulsion mainly composed of silver chloride, which is disclosed in JP-A No. 47-32820, the development speed is fast, but the minimum density cannot be sufficiently reduced.
This results in an unclear image.

Further, Japanese Patent Publication No. 58-1412 discloses silver halide grains in which at least two types of silver halide emulsions each having a different silver chloride content are laminated. Apply chemical sensitization to the inside,
Or, compared to emulsions doped with metal ions, the sensitivity is insufficient, so in order to obtain high sensitivity,
When the particle size is increased, the development speed decreases, making it unsuitable for rapid processing.

In general, silver halide photographic materials are processed with a fixing solution containing a silver halide solvent to remove undeveloped silver halide after development, or color images are created by color development. When obtained, the developed silver and undeveloped silver halide are removed by treatment with a bleaching solution followed by a fixing solution, or with a bleach-fixing solution.

In order to rapidly process silver halide photographic materials, it is desirable to shorten the processing time of each processing step and reduce the number of processing steps, and from this point of view various attempts have been made regarding rapid processing. However, internal latent image type silver halide photosensitive materials can be directly fixed without undergoing development, water washing and/or stop processing, and color photosensitive materials can be directly bleached and fixed to achieve the minimum density. It was found that there was an increase. In particular, the above-mentioned Japanese Patent Application Laid-Open No. 47-3
In the emulsion mainly composed of silver chloride disclosed in No. 2820, a significant increase in minimum density is observed when direct fixing or direct bleach-fixing is performed, and in order to put rapid processing into practical use, significant improvements are required. was found to be necessary.

The present invention is characterized by: (1) maximum density of the image being sufficiently large and minimum density being sufficiently small; (2) development speed being fast; rapid processing in which the minimum density does not increase much even when direct fixing processing or direct bleach-fixing processing is performed after development; A technical problem is to provide a silver halide photographic material having an internal latent image type silver halide emulsion suitable for the present invention.

[Means for Solving the Problems] The present inventor has made extensive studies to solve the above problems, and as a result, has arrived at the present invention.

Specifically, the direct positive silver halide photographic light-sensitive material according to the present invention has at least one silver halide emulsion layer containing internal latent image type silver halide grains whose grain surfaces are not fogged in advance; In a photographic light-sensitive material in which a positive image can be obtained directly by surface development after being subjected to a fogging treatment and/or while being subjected to a fogging treatment, the internal latent image type silver halide grains are chemically sensitized. or a multilayer shell consisting of a core doped with metal ions and at least two layers covering the core, and the outermost layer located at the outermost side of the multilayer shell is a layer adjacent to the outermost layer. It is characterized by silver halide grains having a smaller silver chloride content.

The present invention will be explained in detail below.

In the present invention, the multilayer shell consists of at least two shell layers each having a different silver chloride content, and the outermost layer has a lower silver chloride content than the layer adjacent to the outermost layer. Made of silver halide with

In the present invention, silver halide having any halogen composition can be used for the outermost layer containing silver chloride as long as the silver chloride content is smaller than that of the layer adjacent to the outermost layer. Examples include silver bromide, silver chlorobromide, silver chloroiodobromide, and silver chloroiodide.

The outermost layer of the silver halide grains of the present invention preferably has 8
Those containing 0 mol% or less (including 0%) of silver chloride, more preferably 80 mol% or less (including 0%) of silver chloride are preferred. The silver chloride content of the outermost layer of the silver halide grains of the present invention is preferably 5 mol% or more lower than the silver chloride content of the layer adjacent to the outermost layer, more preferably 10% mol or more lower. be.

The outermost layer of the silver halide grains of the present invention can completely cover the surface of the silver halide grain, or can selectively cover a part of the surface. In the present invention, the outermost layer preferably covers 50% or more of the particle surface.

The outermost layer of the silver halide grains of the present invention has a content of 50 mol% based on the silver halide of the internal latent image type silver halide grains.
The silver halide is more preferably 2 to 30 mol %, particularly preferably 5 to 25 mol %.

In the multilayer shell of the present invention, the layer adjacent to the outermost layer preferably has a silver chloride content that is 5 mol% or more higher than that of the outermost layer. Any silver halide composition may be used as long as it satisfies these conditions. Examples include silver chloride, silver chlorobromide, silver chloroiodide, and silver chloroiodobromide.

The multilayer shell consists of at least an outermost layer and a layer adjacent to it, but it may also have a structure in which layers having different silver halide compositions are laminated, or it may have a structure in which layers having mutually different silver halide compositions are laminated, or in which layers are stacked in the radial direction of the silver halide grains. , a structure in which the silver halide composition changes continuously may be adopted.

The multilayer shell in the silver halide grains of the present invention may be a multilayer shell consisting of more than two layers. In one preferred embodiment of the present invention, a chemically sensitized silver halide core is layered in three layers, for example a first shell of silver bromide, then a second shell of silver chlorobromide, and then a third shell of silver bromide. Mention may be made of silver halide grains coated with a shell.

The core of the silver halide grains of the present invention is silver bromide.

It consists of a silver halide selected from silver iodobromide, silver chlorobromide, silver chloride, silver chloroiodide, and silver chloroiodobromide.

The silver halide grains forming the core grains may have any shape; for example, they may be cubic, octahedral, or a mixture thereof; they may also be spherical, tabular, or
Particles of irregular shape may also be used. Although the average particle size and particle size distribution of the silver halide grains constituting the core of the present invention can be varied widely depending on the desired photographic performance, a narrower particle size distribution is more preferable. That is, the silver halide grains constituting the core of the present invention are preferably substantially monodisperse. Specifically, the silver halide core grains of the present invention are those in which the weight of silver halide that is not 20% away from the average grain size is 60% or more of the total silver halide weight, and particularly preferably 80% or more. It is something. Measurement of the average particle size and particle size distribution of silver halide grains can be carried out, for example, by
The Theory Child weight distribution can be determined using these values in the usual way.

The method for producing the above-mentioned monodisperse core emulsion is, for example,
No. 8-36890, JP-A-54-48520, JP-A No. 54
The double jet method disclosed in Japanese Patent Application No.-65521 and the like can be used. In addition, a premix method described in JP-A-54-158220 and the like may also be used.

The cores of the silver halide grains in the present invention are chemically sensitized or doped with metal ions.

Many methods are known for chemical sensitization. That is,
These sensitization methods include sulfur sensitization, gold sensitization, reduction sensitization, noble metal sensitization, and a combination of these sensitization methods. As the sulfur sensitizer, thiosulfates, thioureas, thiazoles, rhodanines, and other compounds can be used. Such a method is described, for example, in U.S. Pat. No. 1,574,944;
No. 823.498, No. 2,410889, No. 3.85
El, No. 955, etc.

The core of the silver halide grains used in the present invention is 1, for example, U.S. Pat.
As stated in No. 2,842,381, etc.
Sensitization can be carried out with a water-soluble gold compound or with a reduction sensitizer. Such methods are described, for example, in U.S. Pat.
Reference may be made to the descriptions in No. 18,1198, No. 2,983,810, etc.

Furthermore, noble metal sensitization can also be carried out using noble metal compounds such as platinum, iridium, palladium, and the like. Such methods are described, for example, in U.S. Pat.
No. 8,08Q and British Patent No. 81B, (lfi 1) may be referred to.

The core of the silver halide grains in the present invention can be doped with metal ions. To dope the core with metal ions, the metal ions can be added as water-soluble salts, for example, during any process of forming the core particles. Preferred specific examples of metal ions include iridium,
There are metal ions such as lead, antimony, bismuth, gold, osmium, and rhodium. These metal ions are preferably used in amounts of txto-a to IXIQ-4 moles per mole of silver.

It is more preferable that the multilayer shell of the silver halide grain in the present invention covers 50% or more of the surface area of the core which has been chemically sensitized or doped with metal ions. Particularly preferred is one that completely covers the core.

As a method for forming the shell, the double jet method or premix method described above can be used. It is also possible to form the core emulsion by mixing fine grains of silver halide and performing Ostwald ripening.

It is preferable that the silver halide grains of the present invention are not chemically sensitized on the surface of the grains, or are sensitized only to a small extent.

When chemically sensitizing the surface of the silver halide grains of the present invention,
This can be carried out in the same manner as the chemical sensitization of the core particles.

The silver halide grains in the present invention preferably have a narrow grain size distribution even after the formation of a multilayer shell and are substantially monodisperse. That is, it is preferable that the silver halide grains as a whole are substantially monodisperse. Specifically, the silver halide grains of the present invention have a silver halide weight that is not 20% away from the average grain size. This means that the weight of silver oxide is 80% or more, and particularly preferably 80% or more.

The ratio of silver halide between the core and the multilayer shell of the present invention can be arbitrarily determined, but the ratio of the multilayer shell is 10 mol% to 88 mol% based on the total silver halide of the silver halide grains. is preferable.

Regarding the composition ratio of the silver halide grains of the present invention, the proportion of silver chloride in the entire grain is preferably 5 mol % to 80 mol %.

The meaning that the grain surface is not prefogged means that the emulsion used in the present invention is coated on a transparent film support for 35 m
gAg/crn' and developed with the following surface developer A at 20°C for 10 minutes without exposure, the density obtained does not exceed 0.8, preferably 0.4. say.

Surface developer A Metol 2.5g Ascorbic acid 10g NaBO2*4 H2O35g KBr 1g Add water 1st glance Also, the silver halide emulsion according to the present invention can be prepared by exposing the test piece prepared as described above. Internal developer B with the following formulation
It gives sufficient density when developed with.

Internal developer B Metol 2g Sodium sulfite (anhydrous) 80g Hydroquinone 8g Soda carbonate (-hydrate) 52.5g KBr
5g KI Add 0.5g water
More specifically, if a portion of the specimen is exposed to a light intensity scale for a defined period of time up to about 1 second and developed in internal developer B for 10 minutes at 20°C. exhibiting a maximum density that is at least 5 times, preferably at least 10 times, that obtained when another part of the specimen exposed under the same conditions is developed with surface developer A for 10 minutes at 20°C. It is.

The silver halide emulsion according to the present invention can be optically sensitized using commonly used sensitizing dyes. Combinations of sensitizing dyes used for supersensitization of internal latent image type silver halide emulsions, negative-working silver halide emulsions, etc. are also useful for the silver halide emulsions of the present invention. For information on sensitizing dyes, see Research Disc.
losure) No. 151E12 and No. 17
Reference may be made to No. 843.

The photographic light-sensitive material of the present invention is image exposed (photographed) by a conventional method.
After that, a positive image can be easily obtained directly by surface development. That is, the main step of directly creating a positive image is to remove fogging nuclei by chemical or optical action after image exposure of the photographic light-sensitive material having an internal latent image type silver halide emulsion layer that has not been fogged in advance. After performing the process of generating the image, that is, the fogging process, and/
Alternatively, surface development may be performed while performing fogging treatment. Here, the fogging treatment can be carried out using a compound that provides full exposure or generates fogging nuclei, that is, a fogging agent.

In the present invention, the entire surface exposure is carried out by immersing or moistening the image-exposed photosensitive material in a developer or other aqueous solution, and then exposing the entire surface uniformly to light.

The light source used here may be any light within the wavelength range to which the photographic light-sensitive material is sensitive; high-intensity light such as flash light may be applied for a short period of time, or weak light may be applied for a long period of time. . Further, the total exposure time can be varied over a wide range depending on the photographic material, development processing conditions, type of light source used, etc. so as to ultimately obtain the best positive image.

A wide variety of compounds can be used as the fogging agent used in the present invention, and it is sufficient that the fogging agent is present during the development process. (preferably in the silver oxide emulsion layer), or may be contained in the developer or the processing solution prior to development. The amount used can vary widely depending on the purpose, and the preferred amount is 1 to 150 hg, preferably 10 to 100 hg per mole of silver halide when added to a silver halide emulsion layer.
It is 0 mg. When added to a processing solution such as a developer, the preferred amount is 0.01 to 5 g/l, particularly preferably 0.05 to 1 g/l.

Fogging agents used in the present invention include, for example, U.S. Pat.
583,785, hydrazines described in 2,588.11182, or U.S. Pat. No. 3,227
, 552: U.S. Pat. No. 3,815. f315, 3,718
, No. 479, No. 3.719,494, No. 3,734,
Heterocyclic quaternary nitrogen salt compounds described in US Pat. No. 738 and US Pat. No. 3,759,901; and also US Pat.
Examples include compounds having an adsorption group on the silver halide surface, such as acylhydrazinophenylthioureas described in No. 5. Moreover, these fogging agents can also be used in combination.

For example, Research Fist Disc Roger (ResearchD
No. 15182 describes the use of a non-adsorption type fogging agent in combination with an adsorption type fogging agent, and this combination technique is also effective in the present invention.

As the fogging agent used in the present invention, either an adsorption type or a non-adsorption type can be used, and they can also be used in combination.

Specific examples of useful fogging agents include hydrazine hydrochloride,
Phenylhydrazine hydrochloride, 4-methylphenylhydrazine hydrochloride, 1-formyl-2-(4-methylphenyl)hydrazine, 1-7cetyl-2-phenylhydrazine, l-acetyl-2-(4-acetamidophenyl)hydrazine, ! -Methylsulfonyl-2-phenylhydrazine, 1-benzoyl-2-phenylhydrazine, 1
- Hydrazine compounds such as methylsulfonyl-2-(3-phenylsulfonamidophenyl)hydrazine and formaldehyde phenylhydrazine; 3-(2-formylethyl)-2-methylbenzothiazolium bromide, 3-(2-formylethyl) )-2-propylbenzothiazolium bromide, 3-(2-acetylethyl)-2-benzylbenzoselenazolium bromide,
3-(2-acetylethyl)-2-benzyl-5-phenyl-benzoxacilium bromide, 2-methyl-
3-[3-(phenylhydrazino)propyl]benzothiazolium bromide, 2-methyl-3-[3-(p-
) lylhydrazino)propyl] benzothiazolium bromide, 2-methyl-3-[3-(p-sulfophenylhydrazino)propylbenzothiazolium bromide, 2-methyl-3-[3-(p-sulfophenylhydrazino)propyl] phenylhydrazino)pentyl 1benzothiazolium iodide, 1,
2-dihydro-3-methyl-4-phenylpyrido [2,
1-bl benzothiazolium bromide, 1,2-dihydro-3-methyl-4-phenylpyri F [2,1-b
l-5-phenylbenzoxacilium bromide, 4
,4'-ethylenebis(l,2-dihydro-3-methylpyrido[2,L-bl benzothiazolium bromide)
, N-substituted quaternary cycloammonium salts such as 1,2-dihydro-3-methyl-4-phenylpyrido[2,1-bl benzoselenazolium bromide; 5-[1-
Ethylnaphtho(1,2-b)thiazolin-2-ylideneethylidene]-1-(2-phenylcarbazoyl)methyl-3-(4-sulfamoylphenyl)-2-thiohydantoin, 5-(3-ethyl -2-penzothiazolinylidene)-3-[4-(2-formylhydrazino)
phenyl]rhodanine, 1-[4-(2-formylhydrazino)phenyl]3-phenylthiourea, 1.3-
Bis[4-(2-formylhydrazino)phenylcothiourea and the like can be mentioned.

After image exposure, the photographic light-sensitive material having a silver halide emulsion layer according to the present invention is subjected to full-surface exposure or surface development treatment in the presence of a fogging agent to directly form a positive image. This surface development processing method means processing with a developer substantially free of silver halide solvent.

Developers that can be used in the surface developer used for developing the photographic light-sensitive material according to the present invention include common silver halide developers, such as polyhydroxybenzenes such as hydroquinone, aminophenols, and 3-pyrazolidones. , ascorbic acid and its derivatives, reductones, phenylenediamines, etc., or mixtures thereof. Specifically, hydroquinone, aminophenol, N
-Methylaminophenol, 1-phenyl-3-pyrazolidone, 1-phenyl-4,4-dimethyl-3-pyrazolidone, 1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone, ascorbic acid, N,N -diethyl-p-phenylenediamine, diethylamino-0
-Toluidine, 4-amino-3-methyl-N-ethyl-
N-(β-methanesulfonamidoethyl)aniline,
Examples include 4-amino-3-methyl-N-ethyl-N-(β-hydroxyethyl)aniline. These developers can also be included in the emulsion in advance and allowed to act on the silver halide during immersion in a high pn aqueous solution.

The developer used in the present invention can further contain specific antifoggants and development inhibitors, or these developer additives can be optionally incorporated into the constituent layers of the photographic material. be.

Depending on the purpose, various photographic additives such as wetting agents, film property improvers, and coating aids may be added to the silver halide emulsion according to the present invention. Examples of wetting agents include dihydroxyalkanes, and examples of film property improving agents include copolymers of alkyl acrylates or alkyl methacrylates and acrylic acid or methacrylic acid, styrene-maleic acid copolymers, and styrene maleic anhydride. Water-dispersible particulate polymeric substances obtained by emulsion polymerization such as acid half-alkyl ester copolymers are suitable, and examples of coating aids include saponin, polyethylene glycol lauryl ether, and the like. Other photographic additives include gelatin plasticizers, surfactants,
UV absorbers, pH adjusters, antioxidants, antistatic agents,
Thickeners, graininess improvers, dyes, mordants, brighteners, development rate regulators, matting agents, etc. can also be used.

The silver halide emulsion prepared as described above is coated on a support via a subbing layer, an antihalation layer, a filter layer, etc., as necessary, to form an internal latent image type silver halide photographic light-sensitive material of the present invention. obtain.

It is useful to apply the photographic light-sensitive material according to the present invention to color applications, and in this case it is preferable to include cyan, magenta and yellow dye image-forming couplers in the silver halide emulsion. As the coupler, commonly used couplers can be used.

In addition, it is useful to use ultraviolet absorbers such as thiazolidone, benzotriazole, acrylonitrile, and benzophenone compounds to prevent browning caused by short-wavelength actinic rays in dye images.
It is advantageous to use 0, 326, 327, and 328 (all manufactured by Ciba Geigy) alone or in combination.

Examples of the support for the photographic light-sensitive material according to the present invention include polyethylene terephthalate film, polycarbonate film, polystyrene film, polypropylene film, cellulose acetate film, glass, baryta paper, polyethylene laminate paper, etc., which have been subjected to undercoating as necessary. Can be mentioned.

In addition to gelatin, suitable gelatin derivatives can be used as protective colloids or binders in the silver halide emulsion layer according to the present invention, depending on the purpose. Suitable gelatin derivatives include, for example, acylated gelatin, guanidylated gelatin, carbamylated gelatin, cyanoethanolated gelatin, and esterified gelatin.

In addition, in the present invention, other hydrophilic binders (binders) can be included depending on the purpose. Cellulose derivatives such as cellulose acetate, polyacrylamide, imidized polyacrylamide, casein,
Polymerization of vinyl alcohol polymers containing urethane carboxylic acid groups or cyanoacetyl groups, such as vinyl alcohol-vinylaminoacetate copolymers, polyvinyl alcohol, polyvinylpyrrolidone, hydrolyzed polyvinyl acetate, proteins or saturated acylated proteins, and monomers having vinyl groups. Polymers obtained from , polyvinylpyridine, polyvinylamine, polyaminoethyl methacrylate, polyethyleneamine, etc., are added to constituent layers of photographic light-sensitive materials such as emulsion layers, intermediate layers, protective layers, filter layers, backing layers, etc., depending on the purpose. In addition, the hydrophilic binder may further contain a suitable plasticizer depending on the purpose.
It can contain a lubricant or the like.

Further, the constituent layers of the photographic light-sensitive material according to the present invention can be hardened with any suitable hardening agent. These hardeners include chromium salts, zirconiums, aldehydes such as formaldehyde and mucohalogen acids, halotriazine, polyepoxy compounds, ethyleneimine,
Examples include vinyl sulfone hardeners, acryloyl hardeners, and the like.

In addition, the photographic light-sensitive material according to the present invention has, on a support, at least one photosensitive emulsion layer containing the internal latent image type silver halide grains according to the present invention, as well as a filter layer, an intermediate layer,
It is possible to provide a large number of various photographic constituent layers such as protective layers, subbing layers, backing layers, antihalation layers, etc.

When the photographic material of the present invention is used for full color use, at least one red-sensitive silver halide emulsion layer, one green-sensitive silver halide emulsion layer, and one blue-sensitive silver halide emulsion layer are coated on the support. be done. At this time, at least one light-sensitive silver halide emulsion layer may contain internal latent image type silver halide grains according to the present invention, but all light-sensitive silver halide emulsion layers contain internal latent image type silver halide grains according to the present invention. It is preferable that the emulsion layer contains latent image type silver halide grains, and each light-sensitive silver halide emulsion layer may be the same color-sensitive layer or may be separated into two or more layers having different sensitivities. In this case, it is sufficient that at least one color-sensitive layer having a sensitivity difference of 27 degrees contains the internal latent image type silver halide grains according to the present invention, but all the emulsion layers according to the present invention The silver halide grains preferably contain internal latent image type silver halide grains.

The photographic light-sensitive material according to the present invention is suitable for general black and white use, for X-ray use,
For color, for false color, for printing, for infrared, for micro,
It can be effectively applied to various uses such as silver dye bleaching, and is also applicable to colloid transfer method, silver salt diffusion transfer method, Rogers U.S. Pat. No. 3,087.817, Ibid. s8
No. 7 and 2,983. BOB, Weyertz et al., U.S. Pat. No. 3,253,915, Whitemore et al., U.S. Pat. No. 3,227,550°, Barr et al., U.S. Pat.
No. 27,551, U.S. Patent No. 3.227 to Whitemore et al.
, 552 and U.S. Pat. No. 3,415,644 to Rand et al.
No. 3,415,845 and No. 3,415.84θ
It can also be applied to color image transfer methods and color diffusion transfer methods as described in No.

[Effects of the Invention] By using the internal latent image type silver halide emulsion unique to the present invention, the maximum density is sufficiently large, the minimum density is sufficiently small, and the development speed is fast, allowing for direct fixing treatment after development,
It is possible to obtain a highly sensitive silver halide photographic material suitable for rapid processing, in which the minimum density increases little even when directly bleach-fixed.

[Examples] The present invention will be illustrated below with reference to Examples, but the embodiments of the present invention are not limited thereto.

Example 1 A monodisperse core/shell emulsion was prepared as follows.

By controlling the aqueous solution containing gelatin at 50°C and simultaneously adding a silver nitrate aqueous solution and an aqueous solution containing potassium bromide and sodium chloride (molar ratio KBr: NaCM = 30: 70) using a controlled double jet method, the average grain size was reduced. A cubic emulsion with a diameter of 0.25 gtx was obtained. To the core emulsion thus obtained was added 2.0 mg of sodium lithiosulfate per mole of silver, and chemical ripening was performed at 58° C. for 70 minutes. This emulsion is called Emulsion A.

Emulsion A was then divided to obtain the following emulsion.

Emulsion B: Emulsion A was used as a core, and an aqueous solution of silver nitrate and an aqueous solution containing potassium bromide and sodium chloride (in a molar ratio of KBr:NaG!1=30:70) were added simultaneously to obtain an average grain size of 0.35 JLII. A cubic emulsion was obtained. This emulsion is called emulsion B. The obtained emulsion had a narrow particle size distribution and was a monodisperse emulsion.

Emulsion C: Using the emulsion A as a core, a silver nitrate aqueous solution and an aqueous solution containing potassium bromide and sodium chloride (molar ratio KBr:Na1l = 50:50) were added simultaneously to form a cube with an average grain size of 0.35 gm. An emulsion was obtained. This emulsion is called Emulsion C. The resulting emulsion was a monodisperse emulsion.

Emulsion D = Emulsion A was used as a core, and an aqueous solution containing silver nitrate and potassium bromide and sodium chloride (molar ratio KBr:Ha (4=30:70) was added at the same time to give a concentration of 0.33 p, m. grown to particle size,
Subsequently, an aqueous solution containing silver nitrate and an aqueous solution containing potassium bromide and sodium chloride (in a molar ratio of KBr: N
By simultaneously adding a (4=50:50), a cubic emulsion with an average grain size of 0.35 pm was obtained. This emulsion is called an emulsion. The resulting emulsion was a monodisperse emulsion.

Emulsion E: Using Emulsion A as a core, an aqueous solution containing silver nitrate and an aqueous solution containing potassium bromide and sodium chloride (molar ratio KBr:Mail = 50:50) were added simultaneously to grow the emulsion to a grain size of 0.334 m. , followed by an aqueous solution containing silver nitrate and an aqueous solution containing potassium bromide and sodium chloride (KBr:NaCJl in molar ratio).
= 30:70) was added at the same time to obtain a cubic emulsion with an average grain size of 0.35 pm. This emulsion is called Emulsion E. The resulting emulsion was a monodisperse emulsion.

2.0 mg of sodium lithiosulfate per mole of silver was added to the above emulsions B to E, and chemical sensitization was performed at 55° C. for 70 minutes.

A commonly used spreading agent and hardening agent were added to each of the emulsions obtained above, and then the emulsions were coated on a cellulose triacetate support and dried to give a coated silver amount of 3 G+wg/100 crn' to obtain samples.

The obtained sample was exposed to light through an optical wedge for sensitometry using a photosensitive needle (hereinafter referred to as wedge exposure), and exposed to light at 30°C for 30 seconds, 1 minute, 2 minutes, and 3 minutes using a developer with the following formulation. Developed, then washed with water, fixed, washed with water, using conventional methods.
It was dried.

Phenidone 0.4g Sodium sulfite (anhydrous) 75g Hydroquinone 10g Soda carbonate (
- water salt) 40g Potassium bromide 4g 5-methylbenzotriazole 30mg 1-acetyl-2-phenylhydrazine (fogging agent) O, 1g Add water for 1 sentence (adjusted to pH 12.5 with sodium hydroxide) Obtained positive Table 1 shows the results of measuring the maximum and minimum densities of the images.

As is clear from Table 1, the emulsion of the present invention (emulsion D) can quickly provide a good positive image with a large maximum density and a small minimum density.

Example 2 A monodisperse core/shell emulsion was prepared as follows.

While controlling the aqueous solution containing gelatin at 50°C.

An aqueous solution containing equimolar silver nitrate aqueous solution and potassium bromide and sodium chloride (KBr:NaCfL in molar ratio)
=90:10) by a controlled double jet method, a cubic emulsion with an average grain size of 0.35 p, m was obtained. To the core emulsion thus obtained were added 2.0 mg of sodium lithiosulfate and 1.0 mg of potassium chloroaurate per mole of silver, and chemical ripening was performed at 55°C for 120 minutes. This emulsion is referred to as Emulsion F.

Next, emulsion F was divided to obtain emulsions GL as shown below.

Emulsion F was used as a core, and an aqueous solution containing silver nitrate and an aqueous solution containing potassium bromide and sodium chloride (in a molar ratio of KBr:WaC!L=50:5G) were added simultaneously to coat the shell, and the average Particle size 0゜42
A cubic emulsion of ILm was prepared, and then an aqueous solution containing silver nitrate and an aqueous solution containing potassium bromide and sodium chloride (in molar ratio KBr:NaCJl =?5
:25) was added at the same time to further coat the shell to obtain cubic emulsions having the average grain size and the molar ratio of the outermost shell as shown in Table 2.

Table 2 Each emulsion thus obtained contained 2.0 mg of sodium thiosulfate and 1.0 mg of potassium chloroaurate per mole of silver.
was added, and chemical ripening was performed at 55°C for 70 minutes.

The following sensitizing dyes were added to each of the above emulsions G to E.

In addition, the magenta coupler 1-(2,4,B-)lichlorophenyl)-3-(2-chloro-5-octadecylsuccinimidoanilino)-5-pyrazolone was dissolved in a mixed solvent of dibutyl phthalate and ethyl acetate. An emulsion was prepared by dispersing the gelatin in an aqueous gelatin solution.

Next, these emulsified dispersions were added to and mixed with the above emulsion, and a hardener was added so that the amount of coated silver was 20 mg/110.
A sample was obtained by coating the film on a cellulose triacetate support and drying it so that the film was 0 crn''.

These samples were wedge exposed through a yellow filter and developed for 2 minutes at 30° C. in a developer with the following formulation.

g Sodium sulfite (anhydrous) 2g Sodium carbonate (-hydrate) 15g Potassium bromide 1g Benzyl alcohol Add 10w of water
1 (pH 1 with potassium hydroxide)
Adjusted to 0.2. ) However, 1 from 10 seconds after the start of development.
The entire surface was uniformly exposed to white light of ■lux for 0 seconds.

Next, the following formulation was stopped (30°C for 30 seconds), bleach-fixed (30°C for 1 minute and 30 seconds), washed with water, and dried. (Process 1) Stop solution prescription: Aqueous bleach-fix solution containing 3% by weight of glacial acetic acid: 5 g of diammonium ethylenediaminetetraacetate 130 g of ammonium thiosulfate Add 3 g of sodium sulfite (anhydrous)
1 sentence (FHEt with ammonia water, 5
Adjusted to. ) Next, treatment 2 was performed in the same manner as treatment 1. However, the stop treatment was not performed, and the bleach-fixing treatment was performed immediately after development.

Table 3 shows the results of measuring magenta positive images for each sample obtained. However, the sensitivity is expressed as a relative value of the reciprocal of the exposure amount that gives a density of (minimum density 10 maximum density) Xo, 5. Assume that the sensitivity of sample 5 in treatment 1 is 100.

As is clear from the results shown in Margin Table 3 below, it can be seen that the emulsion of the present invention provides a high sensitivity and good positive image with a large maximum density and a small minimum density. It is also seen that even if bleach-fixing is performed immediately after development, the minimum density is small and a good image can be quickly obtained.

Example 3 Using Emulsion F obtained in Example 2 as a core, a core/shell emulsion having a three-layer shell was prepared as follows.

With emulsion F as the core, an aqueous solution containing silver nitrate and an aqueous solution containing potassium bromide and sodium chloride (KBr in molar ratio)
: Add Na (4=90:10) at the same time to 0.3
A cubic emulsion of 9 JLm was prepared, and then an aqueous solution containing silver nitrate, potassium bromide and sodium chloride (in molar ratio KBr:Na1l = 30Nia0) were added simultaneously to form a cubic emulsion of 0.45JLm, and then silver nitrate was added simultaneously. and an aqueous solution containing potassium bromide and sodium chloride (in a molar ratio of KBr:Na(
4=90:10) was added at the same time to obtain a cubic emulsion of 0.47 gm. The emulsion obtained was a monodisperse emulsion. To the emulsion thus obtained, 2.0 mg of sodium lithiosulfate and 1.0 mg of potassium chloroaurate were added per mole of silver.
was added, and chemical ripening was performed at 55°C for 60 minutes. The obtained emulsion is referred to as Emulsion M.

Emulsion M was applied and dried in accordance with Example 2, and the resulting sample was exposed to light in accordance with Example 2, and Process I was performed. Table 4 shows the results of measuring the maximum density, minimum density, and sensitivity of the obtained positive images.

Table 4 As is clear from the results in Table 4, it can be seen that the emulsion of the present invention having a three-layer shell also has good positive performance.

Claims (1)

[Claims] It has at least one silver halide emulsion layer containing internal latent image type silver halide grains whose grain surfaces are not fogged in advance, and after image exposure, after fogging treatment, and/or
Alternatively, in a photographic light-sensitive material in which a positive image can be obtained directly by surface development while being subjected to a fogging process, the internal latent image type silver halide grains are chemically sensitized or doped with metal ions as a core. and a multilayer shell consisting of at least two layers covering the core, and the outermost layer of the multilayer shell has a silver chloride content lower than that of the layer adjacent to the outermost layer. A direct positive silver halide photographic light-sensitive material characterized by being silver grains.