JPS62194247A - Direct positive photographic sensitive material - Google Patents

Abstract

PURPOSE:To obtain a direct positive photographic sensitive material good in graininess by forming at least one emulsion layer composed of an internal latent image type core/shell type direct positive emulsion having an average grain diameter of <=0.25mum. CONSTITUTION:The direct positive emulsion giving effective results is composed of, preferably, monodispersed core/shell type silver halide grains having an average grain diameter of <=0.25mum, preferably, <=0.20mum. The grains may be used alone or in a mixture of some kinds so as to control the average grain diameter to <=0.25mum. The molar ratio of the silver halide grains in the core to those in the shell to be used is optional, but usually, a molar ratio of 1:2-10 is used. It is preferred for both grains to have the same composition, but their compositions may be different from each other.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a direct positive photographic material,
In particular, it relates to a direct positive photographic light-sensitive material that provides photographic characteristics with good graininess.

(Prior art) Conventionally, metal ion doping, chemical sensitization, or both are performed to coat the inner core of silver halide and at least the photosensitive sites of the inner core. The surface of the outer shell consists of an internal latent image type silver halide grain (hereinafter referred to as core/shell type grain) which is chemically sensitized as necessary. It is known that a reversal image can be obtained by a direct reversal method of the type developed in the presence of a detergent or exposed to light during development.For more details, see US Pat. It is described in specifications such as J, No. 761,274.

On the other hand, regarding the graininess of silver halide photographic materials,
Edited by T. H. James, rThe Theory of
the Photographic Proc
essJ Hiroth edition, /ri77 Ma
emilan Publishing Co., Inc.
, p4'0. Although it is known that reducing the total grain size of silver halide grains improves the performance as described in t, it is well known in the art that this also has the disadvantage of accompanied by a decrease in sensitivity. That's true.

In direct positive photosensitive materials using core/shell type grains, the granularity similarly deteriorates as the particle size increases, and the granularity of the entire photosensitive material is determined by the granularity of the emulsion grains with the largest grain size. was there.

(Problems to be Solved by the Invention) An object of the present invention is to provide a direct positive photographic light-sensitive material with good graininess and free from such problems.

(Means for Solving the Problems) The above-mentioned object of the present invention is to provide a direct positive photographic material with an inner layer type core having an average particle size of 0.21 μm or less;
This was achieved by including at least one emulsion layer consisting of a shell direct positive emulsion.

The inventors found that the average particle size was 062! By providing at least one layer consisting of an inner layer type core/shell direct positive emulsion of .mu.m or less, the graininess was successfully improved significantly without depending on the emulsion grains having the maximum grain size. This was completely unthinkable in the past.

The effect of the present invention was first discovered in a direct positive photographic light-sensitive material, and if the graininess of the emulsion grains to be produced is improved in the low-sensitivity region than in the low-density region, the graininess can be improved even in the high-density region. It got better.

The present invention will be explained in detail below.

Known direct positive emulsions can be used in the present invention. For details, see RESEARCHDISCLO8URE Volume 17A It
em / 741131 pages p, λ2 (/ri7 2011/ko month issue), volume 192 It6y11 / 9227 p,
/! ! ~/! t (/910≠month issue) can be used. In the present invention, a core/shell type silver halide emulsion having an internal latent image is preferred. The core/shell type silver halide grains used in the present invention are preferably monodisperse, and have an average grain diameter of O,2
Core/shell type silver halide grains of 1 μm or less, more preferably 0.20 μm or less, give effective results.

As a method for producing such a fine-grain core/shell type emulsion, a method is known in which the degree of chemical sensitization of the inner core is increased, as described in Japanese Patent Application Laid-Open No. 1997-20RJV. The term monodisperse grains refers to silver halide grains of substantially uniform diameter.

The preferred silver halide grains for the present invention are those grains! The average particle diameter is within 4tθ%, preferably within 30% of the average particle diameter.

The core/shell type halogenated steel particles used in the present invention may be used alone or in a mixture of several types to achieve an average particle size of fO.

2! It may be less than μm. Further, an emulsion layer consisting of core/shell type silver halide grains having an average grain diameter of 0.23 μm or more, which is not included in the scope of the present invention, may be further provided.

When using two or more of these core/shell type silver halide grains having different average grain sizes, the emulsion layer containing the core/shell type silver halide grains of the present invention having a smaller average grain size is placed closer to the support. It is desirable that an emulsion layer (lowermost layer) containing core/shell type silver halide grains and gold having a larger average grain size be located farther from the support. The average grain surface diameter of core/shell type silver halide grains with a larger average grain size is O1λj-/, 7 μm.
is preferred. More preferably V! , o, ψ~/, 2μ
m is good. The sensitivity difference between the top layer and the bottom layer is preferably 092 or more (the upper limit is λ-O) in LogE units. Further, two or more types of core/shell type silver halide grains having different average grain diameters may be used in the same layer. Average particle diameter O, ko! The effect of the present invention becomes remarkable when used in combination with core/shell type silver halide grains of μm or more.

The average grain size of silver halide grains is determined by The Photographic Journal.
cJournal) 7 volumes! Pages 30-331 (/ri32
It is determined by weight-averaging the grain sizes of individual silver halide grains measured by the method described in 2010).

The core/shell type silver halide grains constituting all the emulsions of the present invention are first prepared by chemically sensitizing them, doping them with metal ions, or by preparing a silver halide inner core which has been treated with both methods, and then its surface is polished. It is obtained by coating with an outer film of silver halide and further chemically sensitizing the outer film. It is not necessary to cover the entire particle surface of the inner core with the outer film, but it is sufficient to cover at least the photosensitive sites of the inner core (sites that produce photodecomposed silver upon exposure).

Chemical sensitization of the inner core of core/shell type silver halide grains is described by Glafkides
e Photography (Pau1M
Published by ante1, / 1947), V, L, Zelik
"(Making and Coating Photographic Emulsion) Makin" by manet al.
gand Catering Photographic
Emulsion J (The Focal Pr.
ess, 126μ) or H.
Grundlagender Photograp
hisch@n Prozessemit Silbe
rhaloKenidenJ (Akademische
Varlagsgesellschaft/ri, 4
This is carried out using the known method described in F).

In other words, sulfur sensitization using a compound containing sulfur that can react with silver ions or active gelatin, reduction sensitization using a reducing substance, and noble metal sensitization using gold or other noble metal compounds may be used alone or in combination. use Among these, the combination of gold sensitization and sulfur sensitization gives the best results, but depending on the case, reduction sensitization may be used in combination.

As the sulfur sensitizer, thiosulfates, thioureas, thiazoles, rhodanines, and other compounds can be used.
Hirogo, 2. Hiro 10. tr, Ko, λ71.91A7, 2,721,61,1, 3.6! T,? It is listed in the jj issue. Reduction sensitizers include stannous salts, amines, hydrazine derivatives, formamidine sulfinic acid,
Silane compounds etc. can be used, and specific examples thereof include U.S. Pat.
1-No. 2,! /I, No. 491, 2,913. It is described in t09, 2.913,610-J, t91A, and t37. For noble metal sensitization, in addition to total complex salts, complex salts of metals in group II of the periodic table, such as platinum, iridium, and palladium, can be used.
Tata, or3, λ, Hirohiro, oto, British patent t7
r, oti issue, etc.

Conditions for this chemical sensitization step may be determined arbitrarily, but generally the pH is below 0, pAglO is below, temperature ao0
Preferable results are obtained by performing the test at a temperature of c or higher. However, conditions may be set outside this range depending on the case.

The inner core may be chemically sensitized and/or doped with metal ions.The inner core may be doped with metal ions by, for example, during the process of silver halide grain formation or physical ripening of the inner core. , cadmium salts, zinc salts, lead salts, thallium salts, iridium salts, complex salts thereof, rhodium salts or complex salts thereof, iron salts or complex salts thereof, and other metal ion sources may be coexisting.Metal ions are It is usually used in a proportion of io' mole or more per mole of silver halide.

Such a method of treating silver halide of the inner core and coating the surface of the silver halide grains constituting the inner core with silver halide forming the outer shell is known, for example, as described in US Pat.
, 204. Jet issue, same number 3゜317, 312, 1r
s1 J, No. 347,771 (excluding the step of fogging the particle surface), No. J, 761. The methods described in each specification of No. J71 can be advantageously applied.

The ratio of silver halide in the inner core to silver halide in the outer shell is arbitrary, but usually 1 mol of the former to 2 to 70 mol of the latter.
Use moles.

The silver halides of the inner core and outer shell preferably have the same composition, but may have different compositions. In the present invention, silver bromide, silver iodide, silver chloride, silver chlorobromide, silver bromoiodide, silver chloride iodide, etc. can be used as the silver halides. Preferred silver halide emulsions consist of at least about 0 moles of steel bromide, and most preferred emulsions are silver bromide or silver bromoiodide emulsions, especially those containing less than about 10 moles of silver bromide or iodide. .

In the present invention, the core/shell type silver halide grains used in layers other than the bottom layer may have a regular crystal structure such as a cube, a tetradecahedron, or an octahedron, or may have a spherical or tabular shape. irregularities such as irregu
It may have a larl crystal form, it may have a quadruplic form of these crystal forms, or it may be composed of a mixture of particles of various crystal forms.

The core/shell type silver halide grain surfaces prepared as described above are then chemically sensitized.

At this time, the method of chemically sensitizing the inner core described above can be used. At this time, core/
It goes without saying that the chemical sensitization of the surface of the shell type silver halide grains is carried out to the extent that the core/shell type silver halide grains do not impair the characteristics of the internal latent image type. Here, "characteristics as an internal latent image type" means that a silver halide emulsion is coated on a transparent support, exposed for a fixed time of 0.01 to 70 seconds, and then developed using the following developer A (internal type developer). liquid) in
When the silver halide emulsion exposed in the same manner as above was developed with rooc for 3 minutes, the maximum ek degree measured by a normal photographic density measurement method was determined by the following developer B (surface type developer).
It means that the density is at least 5 times higher than the maximum density obtained when developing at 200C for a long time.

Such core/shell type silver halide grains of the present invention are dispersed in a binder in a well-known manner.

As a binder 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, white matter such as albumin and casein; cellulose derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose, and cellulose sulfate esters; sugar derivatives such as sodium alkinate and starch derivatives; can be used.

Examples of gelatin include lime-processed gelatin, acid-processed gelatin, Bull, Soc, Sci, and Photo.

Oxygen-treated gelatin as described in Japan, A/lz, p. 30 (l. 44) may be used, and gelatin hydrolysates and enzymatically decomposed products may also be used.

The internal latent wall type silver halide photographic emulsion of the present invention may be spectroscopically treated with methine dyes and others.

The dyes used include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes,
and hemioxonol dyes. Useful dyes are those belonging to the cyanine dyes, merocyanine dyes and complex merocyanine dyes. Any of the nuclei commonly used for cyanine dyes can be used as the basic heterocyclic nucleus for these dyes. That is, pyrroline nucleus, oxazoline nucleus, thiazoline nucleus, virol nucleus, oxazole nucleus, thiazole nucleus, selenazole nucleus, imidazole nucleus, tetrazole nucleus, pyridine nucleus, etc.; a nucleus in which an alicyclic hydrocarbon ring is fused to these nuclei; and Nuclei in which aromatic hydrocarbon rings are fused to these nuclei, namely, indolenine nucleus, benzindolenine nucleus, indole nucleus, benzoxazole nucleus, naphthoxazole nucleus, benzothiazole nucleus, naphthothiazole nucleus, benzoselenazole nucleus, benz Imidazole nuclei, quinoline nuclei, etc. can be applied. These nuclei may be substituted on carbon atoms.

Merocyanine dyes or complex merocyanine dyes have a ketomethylene structure as the nucleus, such as a pyrazoline-yone nucleus, a thiohydantoin nucleus, and a corchioxazolidine-2 nucleus.
．． ≠-dione nucleus, thiazolidine-2, ≠-dione nucleus, rhodanine nucleus, thiobarbic acid nucleus, etc.! ~6-membered heteroartic ring nuclei can be applied.

Useful sensitizing dyes are disclosed, for example, in the German patent No.
U.S. Pat. No. 2,23/, 611, λ.

≠No. 23, 71♂, same 2. ! 03,77 Otsu No. 2.1
No. 19,007, λ, 9/2.32, J, 1.
jjj, jri≠issue, same 3,1ajt, ta! No. 3
, 672. r97, 3.6 Rihiro, 217, British Patent 1. λ≠λ, jir issue, special public show≠≠-/! It is described in tOJO No. 11C.

Particularly useful methine dyes for use in the present invention include:
It is a cyanine dye having a benzoxazole nucleus and a naphthoxazole nucleus as a basic heterocyclic nucleus. In addition, it is particularly preferable that the bottom layer is spectrally sensitized by such a cyanine dye.

Examples of particularly useful sensitizing dye compounds are illustrated below.

5O3H-N (C2H5)3 D-≠ -r These sensitizing dyes may be used alone or in combination, and the combination of sensitizing dyes is particularly suitable for the purpose of supersensitization. Often used. A typical example is a U.S. patent.
1 otrr, z≠j issue, IWJ-z.

77. λ2 No. 3.3 No. 7,060, No. 3, !
Coco, or2, same j, jλ7,6≠1, same J, t/
7. λri No. 3, same 3. Otsu No. 21,9417, No. 3, 6, No. 420, No. 3. t7ri, 4λr, same 2. ! 03
．． 77 Otsu, same 3.76ri.

30/No. 3. l/≠, tori number, 3,137.1
No. 42, British Patent No. 31A4', No. 21/, Japanese Patent Publication No. 3-μ936, etc.

To prepare a light-sensitive material using the internal latent image type silver halide photographic emulsion of the present invention, the emulsion of the present invention is coated on a support together with other photographic layers as required. The coated bond is optional, but usually has a silver content of about ≠0 to 1 per square foot of support.
A preferable reversal image can be obtained when the coating is applied so that the color is 00.

The support is Re5earch Disclosure
vol.

/7AIID-/76μ3X■page (/9'7J']
Use the vines listed in .

The internal latent scratch type silver halide photographic emulsion of the present invention contains, for example, polyalkylene oxide or its derivatives such as ethers, esters, and amines, thioether compounds, thiomorpholines, etc., for the purpose of increasing sensitivity, increasing contrast, or promoting development. It may also contain quaternary ammonium salt compounds, urethane derivatives, urea visiting conductors, imidazole derivatives, 3-pyrazolidones, and the like. For example, US Patent 2. ≠00゜532, same, 4t co-31 Hari, same λ, 7/l, 0
No. 62, J, t/7,210, No. 3゜772.02
/ issue, same! , No. 101,003, etc. Kumquats can be used.

The internal latent image type silver halide photographic emulsion of the present invention contains antifoggants and stabilizers.
may contain lizerl f. As a compound, Re5
EARCH DISCLOSURE VOLUME, /76
RD-/7tlfi3 (15'7!rJW section contains kumquats.

The internal latent image type silver halide photographic emulsion of the present invention may contain a developing agent. As a developing agent, Re5earchDis
closure vol, /74RD-/741
73 (7tl) Those described in Section XX can be used.

The internal latent image type silver halide photographic emulsions of this invention can be dispersed in colloids that can be hardened by various organic or inorganic hardeners. As a hardening agent, Re5earch Di
closure vol, /7A RD-/7
4 Hiro J (/971) Saletails described in Section X may be used.

The internal latent image type silver halide photographic emulsion F'i of the present invention may contain a coating aid. As a coating aid, 1Research
Disclosure vol, /7ARD-/7
AIAj (/) described in Section 7tlM can be used.

The internal latent image type silver halide photographic emulsion of the present invention can contain so-called color couplers. As a color coupler, Re5search Disclosurevo
1, /7jRD-/7&lAJ (/defr r) Those described in section ① can be used.

The internal latent image type silver halide photographic emulsion of the present invention may also contain an antistatic agent, a plasticizer, a matting agent, a lubricant, an ultraviolet absorber, a fluorescent whitening agent, an air anticaprilant, and the like.

The photographic material produced using the internal latent image type silver halide photographic emulsion of the present invention contains a dye in the photographic emulsion layer or other hydrophilic colloid layer as a filter dye or for various purposes such as preventing/preventing irritation. You may do so. As a dye like this, search Disclos
The one described in item 1 of ure vol, 174 RD-/76 μJ (/defrl) is used.

The internal latent image type silver halide photographic emulsion of the present invention is developed in the presence of a fogging agent (nucleating agent) or developed in full exposure to produce a reversal image. Usable fogging agents include U.S. Patent Nos. J, ZTR, YRA, J,! 63,7t! Hydrazines listed in the issue;
Hydrazines and hydrazones described in No. 3.227°332; British Patent J, or, θ! Acylhydrazines described in No. 7; 21r3.13! No., Special Public Sho≠2-3t Noro≠ No., U.S. Patent J, 611゜411
No. 3.71, ≠ Rihiro No. 3,734A, 731
No., II, No. 0944,613, Dohiro.

//! , sensitizing dyes having a nucleating substituent in the dye molecule; Patent Gu, θJO.

No. 721, 44,031. A typical example is the acylhydrazinophenylthiourea compound described in No. 27. Others, such as U.S. Patent≠, /3ri, 3t7,
Tokukai Akira! Hiro - / 331 ≦ issue - same j Hiro - 7μ72? Compounds described in this issue may also be mentioned.

The amount of fogging agent used here is preferably such as to provide a sufficiently high density when the internal latent image type silver halide emulsion of the present invention is developed with a full surface developer. The fogging agent is preferably added to the photographic emulsion layer or its adjacent layer.

The internal latent image type silver halide photographic emulsion of the present invention can be used for a variety of purposes, including emulsions for direct positive type photographic light-sensitive materials, emulsions for reversal color with a multilayer structure, and emulsions for color diffusion transfer processes with a multilayer structure. usefully used as

The photographic emulsion of the present invention is combined with a color image-providing material for diffusion transfer that releases a diffusible dye in response to development of silver halide, and after appropriate development processing, a desired transfer image is obtained in the received INK. It can also be used for. A large number of such color image-providing materials for diffusion transfer are known, such as those disclosed in U.S. Pat. λ27. j
j≠No. 3, Hiroshi≠3. Ri3ri, PJJ, ≠Hiroshi 3
．． 5P Hiro O, same 3. Ajt, j2≠ issue, 3, 6 r, r 7, 3, 72j, 062, J, 72r
,/No. 73, same J, 7! /, 4LOl, issue, same 3. Takota.

7tO No. 3. Ta 3/, l hiro≠ issue, same 3. ri3ko, 3
t/No. 3. Tar 1.3/ko, 4≠.

0/3,633, 3,232,310, 3.2
5≠, Hiroshi 76, same 3. rill-2, 9g No. 7, same g.
0/j, tJJ-, United States Patent Application Publication (USBIJj
/, t7J, British Patent No. 1170,737, 901
1-. jt4! No., Same/, 0Jlr, J, No. 3/,
West German Patent Application Publication (OLSI/, 30゜xis, 2,2/1, 31/, 221f, 31,1)
No., λ, J/7. / Jμ issue, same co.

Hiro Oko, ri 00, French painting patent ko, ko l≠, /≠θ, Tokukaisho! /-//34co No. 1 (corresponding U.S. patent Hong, 013'
, ≠ 2), same j/-10 Hiro 34A3, special request! Koh wo Hiro No. 333, same! Compounds described in λ-j13/Ir, etc. can be used, but among them, compounds that are initially non-diffusible but cleave after a redox reaction with the oxidation product of the developing agent to release a diffusible dye. It is preferable to use a dye-providing substance (hereinafter abbreviated as DRR compound).

Various known developing agents can be used to develop the photosensitive material of the present invention. Polyhydroxybenzenes such as hydroquinone, co-chlorohydroquinone, λ-methylhydroquinone, catechol, pyrogallol, aminophenols such as p-aminephenol, N-methyl-p-aminophenol, etc.

≠-Diaminophenol, etc.; 3-pyrazolidones, such as /-phenyl-3-pyrazolidones, /-phenyl-Hiro9μm dimethyl-3-pyrazolidone, /-phenyl-Hiroshi-methyl-na-hydroxymethyl-3-pyrazolidone,! ,! -Dimethyl-/-Phenyl-Hira:,/
Ascorbic acids, etc., alone or in combination, can be used.Specifically, the patent application
/j4A// can be used with the developer described in the specification.

Also, to develop a dye image in the presence of a dye-forming coupler, an aromatic-grade amine developing agent, preferably a p-phenylenediamine type developing agent, can be used. Specific examples thereof include q-amino-3-methyl-N,N-dimethylaniline hydrochloride), N,N-diethyl-p-phenylenediamine, and 3-methyl-μmamino-N-ethyl-N-β. -(methane-sulfamide)ethylaniline,
3-Methyl-μm amino-N-ethyl-N-(β-sulfoethyl)aniline, 3-ethoxy-μm amino/-N-
Ethyl-N-(β-sulfoethyl)aniline, ≠-amino-N-ethyl-N-(β-hydroxyethyl)aniline. Such phenomen may be incorporated into the alkaline treated silk composition (processing element) or may be incorporated into a suitable layer of the photosensitive element.

When using a DRR compound in the present invention, any silver halide developer can be used as long as it can cross-oxidize the DRR compound.

The developer may contain preservatives such as sodium sulfite, potassium sulfite, ascorbic acid, and reductones (eg, pyridinohexose reductone).

The photosensitive material of the present invention can be directly developed into a positive image by developing it using a surface developer. Obtainable.

The surface developer is one in which the development process is substantially induced by latent images or fog nuclei on the surface of silver halide grains. Although it is preferable not to include a silver halide solubilizer in the developer solution, unless the internal latent image contributes substantially to the completion of development by the surface development centers of the silver halide grains, silver halide solubilizers (e.g. sulfite Salt) may be omitted.

The developer contains sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate,
May include trisodium phosphate, sodium metaborate, and the like. The content of these agents (fagents) is such that the pH of the developer is from lO to /3, preferably from p)l// to 12.
! Choose as follows.

The developer solution may also contain color development accelerators (such as nitrobenzimitazole). It is advantageous to include compounds commonly used as antifoggants, such as benzotriazoles, such as benzotriazole, !-methyl-benzotriazole, and the like.

The photosensitive material of the present invention can also be processed with a viscous developer.

This viscous developer is a liquid composition containing the processing components necessary for developing the silver halide emulsion and forming a diffusion transfer dye image. It may also contain a hydrophilic solvent. Processing products maintain the pH required for development of the emulsion layer and are produced during the development and dye image formation processes (e.g., hydrohalic acids such as hydrobromic acid, carboxylic acids such as acetic acid, etc.). Contains a sufficient amount of alkali metal to neutralize acids (acids, etc.).

As alkalis, lithium hydroxide, sodium hydroxide,
Alkali metal or alkaline earth metal salts such as potassium hydroxide, calcium hydroxide dispersion, tetramethylammonium hydroxide, sodium carbonate, trisodium phosphate, diethylamine/etc., or amines are used, preferably about 12 Above pH? Motsu, especially p )(/
It is preferable to contain caustic alkali gold at a concentration of tA or more.

When the photosensitive material of the present invention is used in gold diffusion transfer photography, the photosensitive material is preferably in the form of a film unit. A photographic film unit, ie, a film unit which is adapted to be processed by passing it between a pair of juxtaposed suppression members, basically consists of the following three elements:

(Example) Next, the present invention will be specifically explained based on examples.

Example/ Emulsion A-E'? is prepared by the following method. Made by M.

Emulsion A While vigorously stirring an aqueous solution of potassium bromide and an aqueous solution of silver nitrate into an aqueous gelatin solution, the concentration of about 2! A silver bromide emulsion with an average grain size of o and o5P μm was obtained. per mole of silver in this emulsion! A chemical sensitization treatment was performed by adding tomtp sodium thioacetate IJium chloroauric acid (≠water salt) and heating at 7!0C for 10 minutes. Using the silver bromide grain emulsion thus obtained as a core, grains were grown in the same manner as in the first precipitation environment, but while controlling the pAg of the solution to be 7.90, and finally the average grain size was 0. A 23 μm core/shell type monodisperse silver bromide emulsion was obtained. After washing with water and desalting, this emulsion contains 6.0% per mole of silver. λ■
Add sodium thiosulfate and chloroauric acid (≠ hydrate) and ar
Emulsion A was obtained by chemically sensitizing the emulsion by heating it for a minute at 'c.

Emulsion B An aqueous solution of potassium bromide and an aqueous solution of silver nitrate were added to an aqueous gelatin solution for about 20 minutes at ψo'C with vigorous stirring to obtain a silver bromide emulsion with an average particle size of o, or μm.

per mole of silver in this emulsion! Chemical sensitization treatment was carried out by adding sodium thiosulfate chloroauric acid (gluate) of ♂orv and heating at 7!0C for 10 minutes. The entire core of the silver bromide grain emulsion thus obtained was the same as the first precipitation environment, except that the pAg of the solution was 7. The grains were grown while controlling the grain size so that the grain size was O, and finally a core/shell type monodisperse silver bromide emulsion with an average grain size of o and it μm was obtained. After washing with water and desalting Φ, sodium thiosulfate and chloroauric acid (μ hydrate) were added to this emulsion in an amount of 2 to t per mole of silver, and the emulsion was heated at Aj'C for 60 minutes to undergo chemical sensitization treatment to obtain an emulsion Be. Ta.

Emulsion C While vigorously stirring an aqueous solution of potassium bromide and an aqueous solution of silver nitrate into an aqueous gelatin solution, 41! It was added at r0c for about 20 minutes to obtain a silver bromide emulsion with an average grain size of o and it μm. To this emulsion is added thiosulfuric acid at an amount of θO■ per mole of silver.
Chemical sensitization treatment was performed by adding rum chloroauric acid (μ hydrate) and heating at 7j0C for rO minutes. The silver bromide grain emulsion obtained in this way was grown in the entire core at the same time as the first precipitation environment, but controlled so that the pAg of the solution was 7.10, and the final average grain size was 0.3. ! A core/shell type monodispersed silver bromide emulsion of .mu.m was obtained. After washing and desalting, this emulsion contains #1 mole! , add sodium thiosulfate and chloroauric acid (≠ hydrate) at 6!0C.
The emulsion Cyk was obtained by heating for 60 minutes and chemically sensitizing the emulsion.

Emulsion: An aqueous solution of potassium bromide and an aqueous solution of silver nitrate were simultaneously added to an aqueous gelatin solution with vigorous stirring at 7!0C at a cost of about 4 tons to form a silver bromide emulsion with an average grain size of 0゜≠μm. . To this emulsion, sodium thiosulfate and chloroauric acid (≠water salt) were added per mole of silver, respectively, and the emulsion was heated at 7°C for 20 minutes to carry out chemical sensitization.

Using the thus obtained silver bromide grains as cores, they were further grown by further treatment for ≠0 minutes in the same precipitation environment as the first time, and finally octahedral monodisperse core/shell bromide with an average grain size of 0.4 μm was produced. A silver emulsion was obtained. After washing with water and desalting, this emulsion contains 0.0% silver per mole. Add free amount of sodium thiosulfate +
Chemical sensitization treatment was performed by heating at t'c for 60 minutes to obtain internal latent image type silver halide emulsion B.

Emulsion E A silver bromide emulsion was obtained by simultaneously mixing an aqueous solution of potassium bromide and an aqueous solution of silver nitrate into an aqueous gelatin solution with vigorous stirring at 7J0C for about 10 minutes.

3.4 t- of ioo da per mole of precipitated WK silver before precipitation.
per mole of dimethyl-/, 3-thiazoline-2-thione and silver/! t of benzimidazole was added. When the precipitation was completed, crystals with an average particle size of about 7.7 microns were formed. Next to this silver bromide grain is sodium dithiosulfate per mole of silver! A chemical sensitization treatment was carried out by adding 36 μm of potassium chloroaurate per mole of silver and heating at 7!0C for 20 minutes. A core/shell emulsion was prepared by simultaneously mixing aqueous solutions of potassium bromide and silver nitrate with the core emulsion chemically sensitized in this way for about 10 minutes in the same manner as in the first process. The final average particle size is l
, j microns.

Next, to this core/shell type emulsion was added thiosulfate per mol of 1fi and 7 moles of silver ataripoly(N-vinylpyrrolidone) and heated at 600C for 60 minutes to completely chemically sensitize the grain surface. An internal latent image type silver halide emulsion E was obtained.

These emulsions A-H were added with a sensitizing dye D-/'t-/20 to 1 mole of silver, and anhydro-1 as a fogging agent.
j-(j-(phenylhydracillo)butyl)-3-(J
-Sulfopropyl) benzothiazolium hydroxide was added at 257 μm per mole of silver, and coated so that the coating Ag:l was 2.02/m2, and then a gelatin protective layer was coated on top. Shi-pu/~! A sample was prepared.

Next, in the same manner as sample plates 7 to t, except that the emulsion layer was divided into two layers, emulsion D was placed in the upper layer and emulsion C was placed in the lower layer. 31
A multilayer coating was applied so that the thickness was 7 m2 and 0.7 f/m2, and a gelatin retention layer was further applied on top of this to prepare a sample of I6 B.

Sample 7 was prepared in the same manner as Sample AA, except that Emulsion IA was used instead of Emulsion C in the lower layer.

All samples of &t were prepared in the same manner as Sample 7 except that Emulsion E was used instead of the upper layer emulsion.

Sample plate/～! Similarly, except that emulsion B and emulsion C6Ag
After mixing at a ratio of 3: t, the applied Ag amount is 2.0
A total of 77 m2 was coated, and a gelatin protective layer was further coated thereon to prepare a sample of I6 size.

These samples were exposed to tungsten light at a color temperature of 2RJ410/kW for 1 second through a step wedge. One set of each sample was incubated at 36°C using developer C as described below.
The mixture was stirred for 1 minute, then stopped, fixed, and washed with water according to a conventional method to obtain a positive image.

Developer C Hydroquinone ≠Yo? Sodium sulfite / Potassium carbonate Sodium bromide
3f/-phenyl-Hiro-methyl-μ hydroxymethyl-3-pyrazolidone 3t! -Methylbenzotriazole 4tO~add water
with 1tpHk potassium hydroxide //,
Partial and total measurement at transmission density #i, oy of sample prepared and developed in
Measured using a microdensitometer with a char diameter of λμμ, and calculated the root mean square (RMS) of the char diameter,
The value was taken as a measure of graininess.

In other words, root nodules with a large value appear rough. RMS value is 0
．． 01 or more /, 0.0≠λ or more and less than 0.0j 2.0
．． 03μ or more and less than 0.0hiroλ 3.0°02 or more 0.
Gold less than 03 μ, less than U, O, Oλ! It was evaluated as follows.

The measurement results are shown in Table 1.

From Table 7 and Table 1, it can be seen that the samples of the present invention containing at least one emulsion layer consisting of grains having an average grain size of 0.21 μm or less have much better granularity.

Patent applicant Fuji Photo Film Company Procedures Amendment (1)
1986 J 11,)' 11 2. Title of the invention: Direct positive photographic light-sensitive material 3. Relationship with the person making the amendment: Patent applicant: 210-4 Nakanuma, Minamiashigara City, Kanagawa Prefecture. Date of amendment order: Voluntary action. 5. We will submit a revised version of Specification 6, the subject of amendment (with no changes to the content).

Procedural amendment Showa A/year ψ month time and date three

Claims (1)

[Claims] A silver halide direct-positive photographic material comprising at least one emulsion layer consisting of an internal latent type direct-positive emulsion having an average grain size of 0.25 μm or less.