GB2206700A

GB2206700A - High contrast silver halide negative photographic material and processing thereof

Info

Publication number: GB2206700A
Application number: GB08812576A
Authority: GB
Inventors: Nobuaki Inoue; Yoshihiro Takagi; Hiroshi Ayato
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 1987-05-28
Filing date: 1988-05-27
Publication date: 1989-01-11
Anticipated expiration: 2008-05-27
Also published as: JPS63296031A; JPH0814683B2; GB2206700B; GB8812576D0

Abstract

A silver halide photographic material comprises a support having thereon at least one silver halide emulsion layer, wherein the silver halide emulsion layer is composed of a silver halide emulsion containing at least 1 x 10<-6> mol of a rhodium salt per mol of silver, the rhodium content in the shell portions of the silver halide grains of the silver halide emulsion is larger than that in the core portions thereof, and the silver halide emulsion layer or at least one other hydrophilic colloid layer of the material contains a hydrazine compound represented by the general formula (I): <IMAGE> wherein A1 and A2 both represent hydrogen atoms or one of them represents a hydrogen atom and the other represents a sulfinic acid residual group or acyl group, R1 represents an optionally substituted aliphatic, aromatic or heterocyclic group, R<2> represents a hydrogen atom, or an optionally substituted alkyl, aryl, alkoxy, aryloxy or amino group, and G represents a carbonyl group, a sulfonyl group, a sulfoxy group, a phosphoryl group or an iminomethylene group, provided that at least one of R1 and R2 has at least one substituent group which can be disassociated to an anion of which the pKa value is at least 6. Forty such compounds are shown. The silver halide photographic material is imagewise exposed, and subsequently developed with a developing solution containing sulfite ions in an amount of at least 0.15 mol per liter and having a pH of 10.5 to 12.3 so as to form superhigh contrast negative images.

Description

SILVER HALIDE NEGATIVE PHOTOGRAPHIC MATERIAL AND PROCESSING THEREOF This invention relates to silver halide photographic materials and a method for forming superhigh contrast negative images in which these materials are used, and in particular, it relates to superhigh contrast negative type photographic materials which are suitable for the method, and more precisely to photographic materials which can be handled in a bright room, which are used in photomechanical processes.

In the field of graphic arts, it is necessary to use an image-forming system which has the photographic characteristics of superhigh contrast (more precisely, with a gamma value of at least 10) in order to achieve good reproduction of continuous tone images by means of a dot image or good reproduction of line images.

Special developers known as lith developers have been used in the past in order to achieve this objective.

Lith developers contain only hydroquinone as the developing agent and the sulfite which is used as a preservative is used in the form of an adduct with formaldehyde so as not to impair the infectious development properties of the developer, the free sulfite ion concentration being set to a very low level (normally not more than 0.1 mol/liter). Consequently, lith developers are especially liable to aerial oxidation and they have a serious disadvantage in that they cannot withstand storage for more than three days.

The methods in which hydrazine derivatives are used as disclosed in U.S. Patents Nos. 4,224,401, 4,168,977, 4,166,742, 4,311,781, 4,272,606, 4,211,857, 4,243,739 and 4,269,929 exist as methods for achieving high contrast photographic characteristics using stable developers. With these methods high-speed photographic characteristics with superhigh contrast are obtained and moreover the addition of high concentrations of sulfite can be tolerated in the developer and so the stability of the developer in respect of aerial oxidation is- much better than that of a lith developer.

However, although the aforesaid image-forming system is very suitable for a high-speed system of increasing contrast, it is difficult in this system to obtain a low-speed light-sensitive material for bright room use which is widely used for contact work in a photomechanical process. For a low-speed light-sensitive material for bright room, examples of silver halide emulsions containing silver halide grains formed by adding a large amount of rhodium salt are described, for example, in Japanese Patent Applications (OPI) Nos. 125734/81 and 149031/81. (The term "OPI" as used herein means a "published unexamined Japanese patent application").

Also, light-sensitive materials for bright room giving high quality images using a stable processing solution are described in U.S. Patent 4,452,882. However, these known examples do not describe the techniques of obtaining high contrast characteristics using hydrazine.

Processes of obtaining low-speed light-sensitive materials for bright room containing hydrazine are disclosed in Japanese Patent Applications (OPI) Nos.

162246/85, 140338/85 and 238049/86. However, these techniques are yet insufficient in the points of low speed and high contrast.

Also, silver halide emulsions containing a hydrazine compound and a rhodium compound are described in U.S. Patents 4,332,878 and 4,634,661, European Patent 138,200A, etc. However, these photographic emulsions are not a low-speed emulsion for bright room.

The light-sensitive material for bright room in this invention is a light-sensitive material which can be safely used for a long period time under light of wavelengths of substantially longer than 400 nm containing no ultraviolet light component as a safe light.

The object of this invention is, therefore, to provide a technique of not reducing the provision of super-high contrast by a hydrazine compound even by the reduction of sensitivity.

As the result of various investigations, the inventors have solved the aforesaid problems and have discovered a photographic material for bright room utilizing the increase of contrast by a hydrazine compound.

The aforesaid object of the invention has been attained by providing a superhigh contrast negative type silver halide photographic material comprising a support having thereon at least one silver halide emulsion layer, wherein the silver halide emulsion layer is composed of a silver halide emulsion containing at least 1 x 10-6 mol of a rhodium salt per mol of silver, the rhodium content in the shell 'portions of the silver halide grains of the silver halide emulsion is larger than that in the core portions thereof, and the silver halide emulsion layer or at least one other hydrophilic colloid layer of the material contains a hydrazine compound represented by the general formula (I)::

wherein A1 and A2 both represent hydrogen atoms or one of them represents a hydrogen atom and the-other represents a sulfinic acid residual group or acyl group, R1 represents an optionally substituted aliphatic, aromatic or heterocyclic group, R2 represents a hydrogen atom, or an optionally substituted alkyl, aryl, alkoxy, aryloxy or amino group, and G represents a carbonyl group, a sulfonyl group, a sulfoxy group, a phosphoryl group or an iminomethylene group, provided that at least one of R1 and R2 has at least one substituent group - which can be dissociated to an anion of which the pKa value is at least 6, and by providing a method for forming superhigh contrast negative images, wherein the silver halide photographic material described above is imagewise exposed, and subsequently developed with a developing solution containing sulfite ions in an amount of at least 0.15 mol per liter and having a pH of 105 to 12.3.

The hydrazine compounds used in this invention are such that the aliphatic group which is represented by R1 in general formula (I) is a linear chain, branched chain or ring-like alkyl group, alkenyl group or alkynyl group, and preferably has 1 to 60 carbon atoms, and more preferably has 1 to 20 carbon atoms.

The aromatic groups which are represented by R1 are aryl groups which have one or two rings, for example phenyl groups or naphthyl groups, and preferably have 6 to 60 carbon atoms.

The heterocyclic rings which are represented by R1 are saturated or unsaturated three to ten membered heterocyclic rings which have at least one nitrogen, oxygen or sulfur atom and they may consist of a single ring or condensed ring systems including other aromatic rings or heterocyclic rings. The preferred heterocyclic rings are five or six membered aromatic heterocyclic groups and include for example pyridine groups, imidazolyl groups, quinolinyl groups, benzimidazolyl groups, pyrimidyl groups, pyrazolyl groups, isoquinolinyl groups, thiazolyl groups and benzthiazolyl groups.

R1 may be substituted with substituent groups.

Examples of such substituent groups are indicated below.

These groups may also be substituted with, for example, alkyl groups, aralkyl groups, alkoxy groups, aryl groups, substituted amino groups, acylamino groups, sulfonylamino groups, ureido groups, urethane groups, aryloxy groups, sulfamoyl groups, carbamoyl groups, alkylthio groups, arylthio groups, sulfonyl groups, sulfinyl groups, hydroxyl groups, halogen atoms, cyano groups, sulfo groups and carboxyl groups.

Where possible, these groups may be joined together to form a ring.

R1 is preferably an aromatic group and most desirably an aryl group.

The R2 group may have substituent groups and these substituents may be, for example, acyl groups, acyloxy groups, alkyl or aryl oxycarbonyl groups, alkenyl groups, alkynyl groups, or nitro groups, as well as those substituent groups indicated in connection with R1.

These substituent groups may also be substituted with these substituent groups. Furthermore, where it is possible these groups may be joined together to form a ring.

The preferred groups represented by R2 when G is a carbonyl group are hydrogen atom, alkyl groups (for example, methyl group, trifluoromethyl group, 3hydroxypropyl group or 3-methanesulfonamidopropyl group), aralkyl groups (for example, o-hydroxybenzyl group) and aryl groups (for example, phenyl group, 3,5-dichlorophenyl group, o-methanesulfonamidophenyl group or 4methanesulfonylphenyl group); and the group represented by R2 is most desirably a hydrogen atom.

Moreover, when G is a sulfonyl group, R2 is preferably an alkyl group (for example, a methyl group), an aralkyl group (for example, an o-hydroxyphenylmethyl group), an aryl group (for example, a phenyl group) or a substituted amino group (for example, a dimethylamino group).

When G is a sulfoxy group, the preferred R2 groups are cyanobenzyl group or methylthiobenzyl group.

When G is an N-substituted or unsubstituted iminomethylene group, the preferred R2 groups are methyl group, ethyl group and substituted or unsubstituted phenyl group.

When G is a phosphoryl group, R2 preferably represents a methoxy group, an ethoxy group, a butoxy group, a phenoxy group, or a phenyl group and most desirably R2 represents a phenoxy group.

Among R1 and R2, R1 preferably contains the group which is fast to diffusion of a coupler, etc., a so-called ballast group. This ballast group consists of a combination of one or more groups selected from alkyl groups, phenyl groups, ether groups, amido groups, ureido groups, urethane groups, sulfonamide groups , and thioether groups and has at least 8 carbon atoms.

R1 or R2 may have a group XifL1S, which promotes the adsorption of the compound which is represented by the general formula (I) on the surface of silver halide grains; wherein X1 is a group which promotes adsorption on silver halide, L1 is a divalent linking group and m is 0 or 1.

Preferred examples of the groups for promoting adsorption on silver halide which can be represented by X are thioamido groups, mercapto groups and five or six membered nitrogen-containing heterocyclic groups.

The thioamido adsorption-promoting groups which can be represented by X1 are divalent groups which can be represented by the structure

and this may form part of a ring structure or it may be a non-cyclic thioamido group. Useful thioamido adsorption promoting groups can be selected from among those disclosed, for example, in U.S. Patent Nos. 4,030,925, 4,031,127, 4,080,207, 4,245,037, 4,255,511, 4,266,013 and 4,276,364 and in Research Disclosure, Volume 151, No. 15162 (November, 1976) or ibid., Volume 176, No. 17626 (December, 1978).

Actual examples of non-cyclic thioamido groups include thioureido groups, thiourethane groups and dithiocarbamic acid ester groups, and actual examples of cyclic thioamido groups include 4-thiazolin-2-thione, 4imidazolin-2-thione, 2-thiohydantoin, rhodanine, thiobarbituric acid, tetrazolin-5-thione, 1,2,4-triazolin3-thione, 1,3,4-thiadiazolin-2-thione, 1,3,4-oxadiazolin- 2-thione, benzimidazolin-2-thione, benzoxazolin-2-thione and benzothiazolin-2-thione, and these groups may also be substituted.

The mercapto groups of X1 are aliphatic mercapto groups, aromatic mercapto groups or heterocyclic mercapto groups (in cases where there is a nitrogen atom adjacent to the carbon atom which is bonded to the -SH group, these are tautomers of the cyclic thioamido groups and actual examples of these groups are the same as those indicated above).

The five or six membered nitrogen-containing heterocyclic rings which can be represented by X1 are five or six membered nitrogen-containing heterocyclic rings consisting of combinations of nitrogen, oxygen, sulfur and carbon atoms. Of these, the benzotriazoles, triazoles, tetrazoles, indazoles, benzimidazoles, imidazoles, benzothiazoles, thiazoles, benzooxazoles, oxazoles, thiadiazoles, oxadiazoles and triazines are preferred. These groups may also be substituted with appropriate substituent groups. These substituent groups may be those indicated for R1.

The preferred groups for X1 are cyclic thioamido groups (which is to say mercapto substituted nitrogencontaining heterocyclic groups, for example 2mercaptothiadiazole groups, 3-mercapto-1,2,4-triazole groups, 5-mercaptotetrazole groups, 2-mercapto-1,3,4oxadiazole groups, 2-mercaptobenzoxazole groups etc.) and nitrogen-containing heterocyclic groups (for example benzotriazole groups, benzimidazole groups, indazole groups, etc.).

The divalent linking group represented by L1 is an atom or atomic group which contains at least one element selected from among carbon, nitrogen, sulfur and oxygen.

Actual examples of the divalent linking groups represented by L1 include alkylene groups, alkenylene groups, alkynylene groups, arylene groups, -O-, -S-, -NH-, -N=, -CO- and -SO2- (these groups may also have substituent groups) and these groups may be used individually or in combinations.

A1 and A2 are hydrogen atoms, alkylsulfonyl or arylsulfonyl groups which have not more than 20 carbon atoms (preferably phenylsulfonyl groups or substituted phenylsulfonyl groups of which the sum of the Hammett substituent constants is greater than -0.5), acyl groups which have not more than 20 carbon atoms, (preferably benzoyl groups or substituted benzoyl groups such that the sum of the Hammett substituent constants is greater than -0.5), or linear chain, branched chain or cyclic unsubstituted or substituted aliphatic acyl groups (these substituent groups may be, for example, halogen atoms, ether groups, sulfonamido groups, carboxylamido groups, hydroxyl groups, carboxyl groups, sulfonic acid groups, etc.), and the sulfinic acid residual groups represented by A1 and A2 may in practice represent those disclosed in U.S.Patent No. 4,478,928.

A1 and A2 are most desirably hydrogen atoms.

G in general formula (I) is most desirably a carbonyl group.

Of the substituent groups which can be dissociated to anions with pKa values of at least 6, those which can be dissociated to anions with pKa values from 8 to 13 are preferred but no further specification is required provided that the groups are not dissociated to any marked extent in neutral or weakly acidic media but are dissociated to a satisfactory extent in aqueous alkaline solutions (preferably of pH 10.5-12.3) such as developer baths.

For example, these may be hydroxyl groups, groups which can be represented by the formula R3SO2NH- (wherein R3 is an alkyl group, an aryl group, a heterocyclic group or an -L2-X2 group (wherein L2 and X2 have the same significance as the aforementioned L1 and X1, respectively) and these groups may also have substituent groups), mercapto groups, hydroxyimino groups

groups), active methine groups or active methylene groups

The compounds represented by the general formula (I) are preferably those represented by the general formula (II)::

wherein Y1 is a substituent group (in practice the same as the substituent groups of R1 in general formula (I)), or a substituent group which can be dissociated to an anion of a pKa value of at least 6 (in practice the same as in general formula (I)), n has a value of 0, 1 or 2 and when n is 2, the Y1 groups may be the same or different, R4 is the same as R1 in general formula (I) or it represents a tLlYmXl group and it is preferably a -(L1:)-mX1 group (wherein L1 and X1 have the same significance as in general formula (I) and m has a value of 0 or 1), and G, R2, A1 and A2 are the same as in general formula (I).

Moreover the R4SO2NH group is preferably substituted in the position para to the acylhydrazino group.

Actual examples of compounds which can be represented by the general formula (I) are indicated below. However the invention is not limited to these compounds.

The compoundsi s invtion can be synthesized by reference to the methods disclosed, for example, in Japanese Patent Applications (OPI) Nos. 67843/81 and 179734/85.

The compound represented by the general formula (I) is included in a photographic material in this invention; it is preferably included in a silver halide emulsion layer, but it may be included in a lightinsensitive hydrophilic colloid layer (for example in a protective layer, intermediate layer, filter layer, antihalation layer, etc.). In practice the compounds which are used can be added to the hydrophilic colloid layer as an aqueous solution when the compound is water-soluble or as a solution in an organic solvent which is miscible with water, such as alcohols, esters, ketones etc., in cases where the compound is only sparingly soluble in water.

When added to a silver halide emulsion layer, the compounds can be added at any time from the commencement of the chemical ripening process up to the coating stage, but they are preferably added during the period after the completion of chemical ripening before the coating operation. The addition of the compound to the coating liquid which is to be used for coating purposes is especially desirable.

The amount of the compound represented by the general formula (I) in this invention which is added is preferably selected suitably in accordance with the grain size and halogen composition of the silver halide emulsion, the method and extent of chemical sensitization, the relationship between the layer which is to contain the said compound and the silver halide z halide emulsion layer, the type of anti-fogging compounds which are being used, etc.

and the test methods used for making such a selection are well known to those in the industry. Normally the amount used lies within the range from 10-6 mol to lx10-1 mol per mol of silver halide, and preferably it lies within the range from 10-5 mol to 4x10-2 mol, per mol of silver halide.

-The . compounds represented by the general formula (I) can be used conjointly with the hydrazine compounds which were known in the past. Various hydrazine compounds can be used conjointly and examples of such compounds are disclosed in Japanese Patent Application (OPI) Nos. 20921/78, 20922/78, 66732/78 and 20318/78.

The mol ratio for conjoint use is from 0.01 to 100 times, and preferably from 0.1 to 10 times, with respect to the compound of general formula (I).

In the distribution of rhodium in the silver halide grains of this invention, the rhodium content in the core portions is less than that in the shell portions.

For incorporating rhodium in the silver halide grains, it can be added thereto at the preparation of the grains as a neutral salt such as a simple metal salt, a complex salt, etc.

As the rhodium salt, there are rhodium monochloride, rhodium dichloride, rhodium trichloride, hexachlororhodium (III) acid ammonium salt, etc., but water-soluble halogen complex compounds of tri-valent rhodium, such as hexachlororhodium (III) acid and the salts (e.g., ammonium salt, sodium salt, potassium salt, etc.) thereof.

The addition amount of'the water-soluble rhodium salt is at least 1.0 x 10-6 mol, preferably from 1.0 x 10-5 mol to 1.0 x 10-3 mol, and particularly preferably from 5.0 x 10-5 mol to 5.0 x 10-4 mol, per mol of silver halide.

If the content of the rhodium salt is more than 10-3 mol, it becomes impossible to sufficiently increase the contrast. On the other hand, if the content is less than 10-6 mol, a low sensitivity suitable for the lightsensitive materials for bright room cannot be obtained.

In addition to the rhodium salt, a cadmium salt, a lead salt, a thallium salt, or an iridium salt may coexist.

The silver halide for use in this invention is silver chloride, silver chlorobromide, or silver iodochlorobromide, preferably is a silver halide more than 80 mol% of which is composed of silver chloride, and more preferably is silver chlorobromide containing from 0 to 5 mol% silver bromide.

There is fundamentally no restriction on the grain size distribution of the silver halide emulsion, but a monodispersed silver halide emulsion is preferred. A monodispersed emulsion is a silver halide emulsion containing silver halide grains at least 95% by weight or by grain number of which are composed of the grains having sizes within + 40%, and more preferably + 20% of the mean grain size thereof.

The silver halide grains in this invention preferably have a regular crystal form such as cube or octahedron, and particularly preferably have the form of å cube.

The mean grain size of the silver halide constituting the core containing less rhodium for use in this invention is from 0.01 um to 0.12 um, and preferably from 0.02 pm to 0.08 pm, and also silver halide grains having narrow distribution so that the deviation of the grain sizes from the mean grain size is within i40%, and preferably within i 20%.

In the present invention, the final mean grain size of the silver halide having on the core a shell having a higher content of rhodium is preferably not larger than 0.15 um and more preferably from 0.05 um to 0.12 pm.

The rhodium distribution in silver halide can be determined by successively etching the silver halide grains with a proper amount of a solution of (NH4)2S203 of a proper concentration in several times, determining the silver amount and the rhodium amount in each solution, and converting the determined values into the volume of the grains. The determination can be performed by for example an atomic absorption method.

The rhodium content of the core portion is preferably 1.0 x 10-6 to 5 x 10-5 mol per mol of silver and the rhodium content of the shell portion is preferably 1.0 x 10-5 to 5 x 10-4 mol per mol of silver.

In the mixing condition for preparing the silver halide being used in this invention, it is preferred to prepare the silver halide at a silver potential of at least 100 mV under a sufficiently high stirring speed so that the reaction mixture is uniformly mixed at temperature of not higher than 500C, and preferably not higher than 400C and at pH of 3 to 8, and preferably 5 to 7.

The core portions having a low rhodium content in this invention are prepared as follows. In the case of silver chloride, the silver chloride grains having a preferred narrow distribution are obtained in the presence of a predetermined amount of rhodium, at a reaction temperature of not higher than 400C, at a silver potential of at least 100 mV, and preferably from 200 mV to 450 mV, and for a grain-forming time of from 30 seconds to 20 minutes, and preferably from one minute to 10 minutes. For forming the shell portions having a high rhodium content, a good result is obtained after the formation of the aforesaid core portion at a reaction temperature of not higher than 400C, at a silver potential of at least 100 mV, and preferably from 150 mV to 250 mV, and for a grain-forming time of 2 minutes to 30 minutes, and preferably from 4 minutes to 15 minutes.

The constitution of the core portion having a low rhodium content and the shell portion having a high rhodium content can be optionally selected in the range of from 1 : 100 to 100 : 1, and preferably from 1 : 10 to 10 : 1 by volume ratio.

For incorporating - the aforesaid water-soluble rhodium salt in silver halide grains, it is preferred to add the rhodium salt to an aqueous solution of a watersoluble silver salt or an aqueous solution of a watersoluble halide in the case of simultaneously mixing the water-soluble silver salt aqueous solution and the watersoluble halide aqueous solution. . Or, in the case of simultaneously mixing the water-soluble silver salt aqueous solution and the water-soluble halide aqueous solution, a solution of the rhodium salt is used as a 3rd solution, and silver halide grains may be prepared by simultaneously mixing the three solutions.

In the case of silver chloride fine grains, the growth of the grains sometimes occurs in not only the grain-forming step but also a washing step and a dispersing step owing to the high solubility thereof, the temperature is not higher than 400C, and preferably not higher than 350C,or a nucleic acid, a mercapto compound, a tetraazaindene compound, etc., for controlling the growth of the grains may - coexist in the system.

The silver halide photographic materials of this invention may contain organic desensitizing agents. The organic desensitizing agents which have at least one water-soluble group or an alkali-dissociable group are preferred.

The organic desensitizing agents used in the invention are specified by their polarographic half-wave potential, which is to say the oxidation-reduction potential as determined polarographically, the sum of the polarographic cathode and anode potentials being positive.

The method of measuring the polarographic oxidationreduction potential is disclosed, for example, in U.S.

Patent No. 3,501,307. The water soluble groups of which at least one is present in the organic desensitizing agent may be in practice sulfonic acid groups, carboxylic acid groups or phosphonic acid groups, etc., or salts of these groups with an organic base (for example, ammonium, pyridine, triethylamine, piperidine, morpholine) or an alkali metal (for example, sodium, potassium).

The alkali dissociable groups are substituents which undergo a de-protonation reaction at the pH of a developer solution (normally in the range from pH 9 to pH 13, but developers may have a pH value outside this range) or at lower pH values to form anions. Actual examples include substituent groups in which at least one hydrogen atom is bonded to a nitrogen atom, such as substituted or unsubstituted sulfamoyl groups, substituted or unsubstituted carbamoyl groups, sulfonamide groups, acylamino groups, substituted or unsubstituted ureido groups, etc., and hydroxyl groups.

Furthermore, heterocyclic groups which have a hydrogen atom on the nitrogen atom which forms the heterocyclic ring of a nitrogen-containing heterocyclic ring may also be included among the alkali dissociable groups.

These water-soluble and alkali-dissociable groups may be connected to any part of the organic desensitizing agent and two or more types of these groups may be present at the same time.

Actual examples of the preferred organic desensitizing agents which can be used in the invention are disclosed in Japanese Patent Application No. 209169/86 and some examples from among these compounds are shown below.

The organic desensitizing agents are preferably included at a rate of l.0x10-8 to 1.0x10-4 mol/square meter, and most desirably at the rate of 1.0x10-7 to 1.0x10-5 mol/square meter in the silver halide emulsion layer.

Water soluble dyes may be included as filter dyes or for the prevention of irradiation as well as for a variety of other purposes in the emulsion layers or other hydrophilic colloid layers in this invention. Dyes for reducing the photographic sensitivity and preferably ultraviolet absorbers which have a spectral absorption maxima in the region of the intrinsic sensitivity of silver halides and dyes which principally absorb light essentially in the region from 350 nm to 600 nm for raising the safety to safe lights when the materials are being handled as bright room-type photosensitive materials can be used as filter dyes.

These filter dyes are preferably added to the emulsion layer or added along with a mordant and fixed in a light-insensitive hydrophilic colloid layer above the silver halide emulsion layer, which is to say remote from the silver halide emulsion layer in connection with the support, depending on the intended purpose of the dyes.

The amount differs according to the molar extinction coefficient of the dye, but it is normally within the range from 10-2 grain/square meter to 1 gram/square meter. The preferred rate of addition is from 50 mg to 500 mg/square meter.

Actual examples of such dyes have been disclosed in Japanese Patent Application No. 209169/86 and some of these are indicated below.

The above mentioned dyes are dissolved in a suitable medium (for example water, alcohol (e.g., methanol, ethanol, propanol, etc.) acetone, methylcellosolve, etc. or mixture of these solvents) and added to the coating liquid which is used for the light-insensitive hydrophilic colloid layer in this invention. Combinations of two or more of these dyes can be used.

The dyes of this invention are used in the amounts required to enable the materials to be handled in a bright room.

The actual amounts of the dyes used is generally between 10-3 gram/square meter and 1 gram/square meter and the preferred amount can be found within the range from 10-3 gram/square meter to 0.5 gàm/square meter.

The use of gelatin as the protective colloid or binder for the photographic emulsion is advantageous but other hydrophilic colloids can be used for this purpose.

For example, gelatin derivatives, graft polymers of gelatin with other polymers, proteins such as albumin or casein, etc., cellulose derivatives such as hydroxyethylcellulose, carboxymethylcellulose, cellulose sulfate esters, etc., sugar derivatives such as sodium alginate, starch derivatives, etc., and a variety of synthetic hydrophilic polymeric materials such as poly(vinyl alcohol), partial acetals of poly(vinyl alcohol), poly-Nvinylpyrrolidone, poly(acrylic acid), poly(methacrylic acid), polyacrylamide, polyvinylimidazole, polyvinylpyrazole, etc. either as homopolymers or copolymers can be used for this purpose.

Acid-treated gelatin can be used for the gelatin as well as lime-treated gelatin and it is also possible to use gelatin hydrolyzates and enzymitically decomposed gelatins.

The silver halide emulsion used in this invention may or may not be chemically sensitized. Sulfur sensitization, reduction sensitization and noble metal sensitization methods are known for the chemical sensitization of silver halide emulsions and any of these methods can be used individually or conjointly for chemical sensitization.

The gold sensitization method from among the noble metal sensitization methods is typical of these methods and here a gold compound, principally in the form of a gold complex salt, is used. Complex salts of noble metals other than gold, for example, platinum, palladium, iridium, etc., can also be included. Actual examples have been disclosed in U.S. Patent No. 2,448,060 and British Patent No. 618,061.

A variety of sulfur compounds, for example thiosulfates, thioureas, thiazoles, rhodanines, etc., can be used as well as the sulfur compounds which are contained in the gelatin as sulfur sensitizers.

Stannous salts, amines, formamidinesulfinic acid, silane compounds, etc. can be used as reduction sensitizers.

The known spectral sensitizing dyes may also be added to the silver halide emulsion layers which are used in the invention.

A variety of compounds can be included in the photographic materials of this invention with a view to preventing the occurrence of fogging during the manufacture, storage or photographic processing of the photographic material or to stabilizing the photographic performance of the material. That is to say, it is possible to add many compounds which are known as antifoggants and stabilizers, such as azoles, for example benzothiazolium salts, nitroindazoles, chlorobenzimidazoles, bromobenzimidazoles, mercaptothiazoles, mercaptobenzothiazoles, mercaptothiadiazoles, aminotriazoles, benzothiazoles, nitrobenzotriazoles, etc.; mercaptopyrimidines; mercaptotriazines; thioketo compounds such as oxazolinthione; azaindenes, for example triazaindenes, tetraazaindenes (especially 4-hydroxy substituted (1,3,3a,7)tetraazaindenes), penta azaindenes, etc.; benzenethiosulfonic acids, benzene sulfinic acids, benzenesulfonic acid amide, etc. From among these compounds, the use of the benzotriazoles (for example, 5methylbenzotriazole) and the nitroindazoles (for example, 5-nitroindazole) is preferred. These compounds may also be included in the processing baths.

Inorganic and organic hardening agents may also be included in the photographic emulsion layers or other hydrophilic colloid layers of the photographic materials of this invention. For example chromium salts (chrome alum, etc.) aldehydes (glutaraldehyde, etc.), N-methylol compounds (dimethylol urea, etc.), dioxan derivatives, active vinyl compounds (1,3,5-triacryloyl-hexahydro-striazine, l,3-vinylsulfonyl-2-propanol, etc.), active halogen compounds (2,4-dichloro-6-hydroxy-s-triazine, etc.) and mucohalogen acids etc. can be used individually or in combinations.

Various surfactants can also be included for various purposes in the photographic emulsion layers or other hydrophilic colloid layers of the photographic materials of this invention, for example as coating aids, for improving the anti-static and sliding properties, for emulsification and dispersion purposes, for the prevention of sticking and for improving photographic performance (for example, for accelerating development, enhancing contrast, sensitization), etc.

For example it is possible to use non-ionic surfactants such as saponin (steroid based), alkyleneoxide derivatives (for example poly(ethylene glycol), poly(ethylene glycol)/poly(propylene glycol) condensates, poly(ethylene glycol) alkyl ethers or poly(ethylene glycol) alkyl aryl ethers, poly(ethylene glycol) esters, poly(ethylene glycol) sorbitane esters, poly(alkylene glycol) alkylamines or amides, poly(ethyleneoxide) adducts of silicones, etc.), glycidol derivatives (for example alkenylsuccinic acid polyglyceride, alkylphenol polyglyceride), fatty acid esters of polyhydric alcohols, alkyl esters of sugars, etc.; anionic surfactants which contain acidic groups such as carboxyl groups, sulfo groups, phospho groups, sulfate ester groups, phosphate ester groups, etc., such as alkylcarboxylic acid salts, alkylsulfonic acid salts, alkylbenzenesulfonic acid salts, alkylnaphthalenesulfonic acid salts, alkyl sulfate esters, alkyl phosphate esters, N-acyl-N-alkyltaurines, sulfosuccinic acid esters, sulfoalkylpolyoxyethylenealkyl- phenylethers, polyoxyethylenealkylphosphate esters, etc.; amphoteric surfactants such as amino acids, aminoalkyl sulfonic acids, aminoalkyl sulfuric acid or phosphoric acid esters, alkyl betaines, amine oxides, etc.; and cationic surfactants such as alkylamine salts, aliphatic or aromatic quaternary ammonium salts, heterocyclic quaternary ammonium salts such as pyridinium and imidazolium quaternary ammonium salts, and aliphatic group- or heterocyclic ring-containing phosphonium or sulfonium salts.

The preferred surfactants for use in this invention are the polyalkyleneoxides of molecular weight at least 600 which are disclosed in Japanese Patent Publication No. 9412/83. Furthermore, a polymer latex such as a poly(alkyl acrylate) latex may also be included to provide dimensional stability.

As the support for the photographic material of this invention, cellulose triacetate, cellulose diacetate, nitrocellulose, polystyrene, polyethylene terephthalate, etc., can be used.

It is preferred to use a vinylidene chloride copolymer latex for a subbing layer.

Various compounds which contain nitrogen or sulfur atoms are effective as well as the compounds disclosed in Japanese Patent Applicationg(OPI) Nos. 77616/78, 37732/79, 137133/78, 140340/85 and 14959/85 as development accelerators and accelerators for the nucleation infectious development which are suitable for use in the invention.

Actual examples are indicated below.

The optimum amounts of these accelerators to be added differ according to the type of compound, but an amount within the range of 1.0x10-3 to 0.5 gram/square meter and preferably with the range of 5.0x10-3 to 0.1 gram/square meter is used.

These acceleratórs are dissolved in a suitable solvent (water, an alcohol such as methanol, ethanol, etc., acetone, dimethylformamide, methylcellosolve, etc.) and added to the coating liquid. A plurality of these additives can be used conjointly.

It is not necessary to use the conventional infectious -' development baths or the highly alkaline development of pH approaching 13 as disclosed in U.S.

Patent No. 2,419,975, and stable development baths can be used to realize enhanced contrast photographic characteristics using the silver halide photographic materials of this invention.

That is to say, the silver halide photographic materials of this invention can provide an adequate superhigh-contrast negative image when a developing of pH 10.5 to 12.3, and preferably of pH 11.0 to 12.0 and which contains at least 0.15 mol/liter of sulfite ion as a preservative is used.

No special limitation is imposed on the developing agents which can be used in the method according to this invention and for example dihydroxybenzenes (for example, hydroquinone), 3-pyrazolidones (for example 1-phenyl-3pyrazolidone, 4,4-dimethyl-l-phenyl-3-pyrazolidone), aminophenols (for example N-methyl-P-aminophenol) etc. can be used individually or in combinations.

The silver halide photographic materials of this invention are particularly suitable for processing in developing baths which contain dihydroxybenzenes as the developing agent and 3-pyrazolidones or aminophenols as auxiliary developing agents. In the preferred developing baths, the dihydroxybenzenes are used at a concentration of 0.05 to 0.5 mol/liter conjointly with 3-pyrazolidones or aminophenols at a concentration of not more than 0.06 mol/liter.

The rate of development can be increased and the development time can be shortened by adding amines to the developing bath as disclosed in U.S. Patent No. 4,269,929.

Moreover pH buffers such as the sulfites, carbonates, borates and phosphates of alkali metals, development inhibitors such as bromides, iodides and organic anti-foggants (especially nitroindazoles or benzotriazoles) and anti-foggants, etc., can also be included in the developing bath. Furthermore where required hard water softening agents, dissolution aids, toning agents, development accelerators, surfactants (the polyalkyleneoxides mentioned earlier are especially desirable), defoaming agents, hardening agents, agents for preventing silver contamination of the film (for example 2-mercaptobenzimidazole sulfonic acid, etc.) may also be included.

Fixing baths of the compositions generally used can be used for the fixing bath. The organic sulfur compounds which are known to be effective as fixing agents can be used as the fixing agent as well as thiosulfates and thiocyanates. The fixing solution may contain watersoluble aluminum salts as a hardening agent.

The processing temperature in the method of this invention is normally selected within the range from 180G to 500C.

The use of an automatic developing machine is preferred for photographic processing and with the method of this invention it is possible to obtain photographic characteristics with sufficiently superhigh-contrast negative tones with total processing times from the point at which the photographic material enters the automatic processor to the point at which it leaves the processor of from 90 to 120 seconds.

The compounds disclosed in Japanese Patent Application (OPI) No. 24347/81 can be used in the developing baths in this invention as agents for preventing the occurrence of silver staining. The compounds disclosed in Japanese Patent Application (OPI) No. 267759/86 can be used as dissolution aids which are added to the developing bath. Moreover the compounds disclosed in Japanese Patent Application (OPI) No.

93433/85 or the compounds disclosed in Japanese Patent Application (OPI) No. 186259/87 can be used as the pH buffers which are used in the developing baths.

The invention is described in detail below by means of examples.

A developing bath of which the composition is indicated below was used in these examples.

Developing Bath Hydroquinone 45.0 grams N-Methyl-aminophenol 12sulfate 0.8 grams Sodium hydroxide 18.0 grams Boric acid 78.0 grams Potassium sulfite 110.0 grams Ethylenediamine tetra-acetic acid, 1.0 gram disodium salt 2-Mercaptobenzimidazole-5-sulfonic acid 0.3 gram Potassium bromide 6.0 grams 5-Methylbenzotriazole 0.6 gram 3-Diethylamino-1,2-propanediol 20.0 grams Water to make 1 liter (pH=11.6) EXAMPLE By the following methods, emulsions [A], [B], [ C ] , [ D ] , [E] and [F] were prepared.

[Emulsion A] To an aqueous gelatin solution kept at 400C were simultaneously added an aqueous silver nitrate solution and an aqueous sodium chloride solution containing 5 x 105 mol of (NH4)3RhCl6 per mol of silver over a period of 3 minutes while controlling the silver potential at 200 mV to provide core grains having a grain size of 0.08 pm.

Therefore, an aqueous silver nitrate solution and an aqueous sodium chloride solution containing 1.5 x 10-4 mol of (NH4)3RhC16 per mol of silver were simultaneously added to the aforesaid system while controlling the silver potential at 100 mV to provide silver chloride cubic grains having a mean grain size of 0.12 um and containing 1 x 10-4 mol/mol-silver of total rhodium.

[Emulsion B] In an aqueous gelatin solution kept at 300C, core grains having a grain size of 0.05 um and containing 5 x 10-5 mol of (NH4)3RhCl6 were formed and further shell portions containing 1.5 x 10-4 mol of (NH4)3RhCl6 were deposited thereon by the same manner as the case of preparing [Emulsion A] to provide silver chloride cubic grians having a mean grian size of 0.08 um and containing 1 x 10-4 mol/mol-silver of total rhodium.

[Emulsion C] To an aqueous gelatin solution kept at 400C were simultaneously added an aqueous silver nitrate solution and an aqueous solution of sodium chloride and potassium bromide containing 1 x 10-5 mol of (NH4)3RhCl6 over a period of 4 minutes while controlling the potential at 300 mV to provide silver chlorobromide (Br: 4 mol%) core grains having a mean grain size of 0.06 urn. Thereafter, an aqueous silver nitrate solution and an aqueous sodium chloride solution containing 1.9 x 10-5 mol of (NH4)3RhCl6 were simultaneously added to the system over a period of 8 minutes while controlling the silver potential at 200 mV to provide silver chlorobromide (Br: 2 mol%) cubic grains having a mean grain size of 0.10 urn and containing 1 x 10-4 mol/mol-silver of total rhodium.

[Emulsion D] To an aqueous gelatin solution kept at 300C were simultaneously added an aqueous silver nitrate solution and an aqueous sodium chloride solution containing 1 x 10-4 mol of (NH4)3RhC16 while controlling the silver potential at 200 mV to provide core grains having a mean grain size of 0.05 urn and then an aqueous silver nitrate solution and an aqueous sodium chloride solution were simultaneously added to the system over a period of 6 minutes to provide silver chloride cubic grains having a mean grain size of 0.08 ijm and containing 5 x 10-5 mol/mol-silver of total rhodium.

[Emulsion E] By the same manner as Emulsion D, silver chloride cubic grains having a mean grain size of 0.08 iim and containing 1 x 10-4 mol/mol-silver of total rhodium were prepared.

[Emulsion F] To an aqueous gelatin solution kept at 400C were simultaneously added an aqueous silver nitrate solution and an aqueous sodium chloride solution containing 1.5 x 10-4 mol of (NH4)3RhCl6 over a period of 3 minutes while controlling the silver potential at 200 mV to provide core grains having a mean grain size of 0.08 urn. Thereafter, an aqueous silver nitrate solution and an aqueous sodium chloride solution containing 5.0 x 10-5 mol of (NH4)3RhCl6 were simultaneously added to the system over a period of 6 minutes while controlling the silver potential at 100 mV to provide silver chloride cubic grains having a mean grain size of 0.12 urn and containing 1 x 10-4 mol/molsilver of tatal rhodium.

In the case of each emulsion, after removing soluble salts, gelatin was added to the emulsion and also 2-methyl-4-hydroxy-l,3,3a,7-tetrazaindene was added thereto as a stabilizer without applying chemical ripening.

Each emulsion was summarized in Table 1 below Table 1 Emul- Grain Size Rhodium Content* sion Core Mean Value Core Shell Mean Value Dispersion Halogen ( m) ( m) (mol/mol-Ag) (mol/mol-Ag) (mol/mol-Ag) Coefficient** Composition A 0.08 0.12 5 x 10-5 1.5 x 10-4 1 x 10-4 12% AgCl B 0.05 0.08 5 x 10-5 1.5 x 10-4 1 x 10-4 10% AgCl C 0.06 0.10 1 x 10-5 1.9 x 10-4 1 x 10-4 13% AgClBr (Cl/Br=98/2 by mol) D 0.05 0.08 1 x 10-4 - 5 x 10-5 10% AgCl E 0.05 0.08 2 x 10-4 - 1 x 10-4 10% AgCl F 0.08 0.12 1.5 x 10-4 5 x 10-5 1 x 10-4 10% AgCl *The distribution of rhodium was obtained by performimg successive etching by the method desoribed in the specification, determining the silver ion and rhodium concentration thus dissolved, and converting the values into volumes. The measured values coincided well with the formula for emulsion preparation.

**Dispersion coefficient : (Standare deviation/mean grain size ) x 100 Then, after adding each hydrazine compound of general formula (I) shown in Table 2 below to each emulsion, the nucleation accelerator shown below was added thereto in an amount of 15 mg/m2;

and further after adding thereto a polyethyl acrylate latex in an amount of 30% by weight as solid based on the amount of gelatin and 1,3-divinylsulfonyl-2-propanol as a hardening agent, the mixture obtained was coated on a polyester support at a silver amount of 3.8 g/m2. The amount of gelatin in the emulsion layer was 1.8 g/m2.

Then, a layer composed of 1.5 g/m2 of gelatin and 0.3 g/m2 of polymethyl methacrylate having a particle size of 1.5 urn was formed thereon as a protective layer.

Each of these samples was exposed through an optical wedge by a printer for bright room, P-607 (made by Dainippon Screen Mfg. Co., Ltd.), developed by using an FG-660F type automatic developing machine (manufactured by Fuji Photo Film Co., Ltd.) for 30 seconds at 380C, fixed, washed and dried. As the fixing solution, GR-Fl (a fixing solution for Fuji's GRANDEX) was used.

The photographic characteristics of the samples were shown in Table 2.

Table 2 Photographic Kind of Compound (I) Characteristics Sample No. Emulsion Kind Amount Y Dmax (mol/mol-Ag) 1 A (1) 2.5 x 10-4 14.2 5.3 2 n n 5 x 10-4 14.8 5.4 3 n (8) 2.5 x 10-4 16.8 5.7 4 n n 5 x 10-4 18.0 5.8 5 H (21) 2.5 x 10-4 17.8 5.7 6 n n 5 x 10 4 21.0 5.8 7 B (1) 2.5 x 10-4 15.0 5.3 8 " " 5x 10-4 15.8 5.5 9 " (8) 2.5 x 10-4 17.0 5.6 10 n n 5 x 10-4 18.8 5.8 11 C (8) 2.5 x 10-4 18.0 5.5 12 n n 5 x 10-4 19.6 5.8 13 " (21) 2.5 x 10-4 20.0 5.8 14 " n 5 x 10-4 22.0 5.9 15 D (8) 2.5 x 10-4 10.8 4.6 16 " " 5 x 10-4 12.4 4.8 17 E " 2.5 x 10-4 8.0 4.3 18 n n 5 x 10-4 9.6 4.4 19 F n 2.5 x 10-4 12.0 4.7 20 n " 5 x 10-4 12.8 4.9 21 A Comparative 5 x 10-4 7.8 4.0 Compound A 22 n n 1 x 10-3 9.0 4.3 23 n Comparative 1 x 10-3 7.0 4.0 Compound B 24 n n 3 x 10-3 7.2 4.1 In Table 1 above: Dmax: Shown by the density value at a point of lower than the sensitivity point by 0.5 as the value of logE.

Gradation (y): The inclination of a straight line connecting the point of density 0.3 and the point of density 3.0 in the characteristic curve.

A larger value shows a higher contrast.

Comparative Compound:

As is clear from Table 1, it can be seen that Sample Nos. 1 to 14 of this invention have higher contrast than comparison samples.

Claims

CLAIMS:

1. A silver halide photographic material comprising a support having thereon at least one silver halide emulsion layer, wherein the silver halide emulsion layer is composed of a silver halide emulsion containing at least 1 x 10-6 mol of a rhodium salt per mol of silver, the rhodium content in the shell portions of the silver halide grains of the silver halide emulsion is larger than that in the core portions thereof, and the silver halide emulsion layer or at least one other hydrophilic colloid layer of the material contains a hydrazine compound represented by the general formula (I)::

wherein A1 and A2 both represent hydrogen atoms or one of them represents a hydrogen atom and the other represents a sulfinic acid residual group or acyl group, R1 represents an optionally substituted aliphatic, aromatic or heterocyclic group, R2 represents a hydrogen atom, or an optionally substituted alkyl, aryl, alkoxy, aryloxy or amino group, and G represents a carbonyl group, a sulfonyl group, a sulfoxy group, a phosphoryl group or an iminomethylene group, provided that at least one of R1 and R2 has at least one substituent group which can be dissociated to an anion of which the pKa value is at least 6.

2. A silver halide photographic material as in Claim 1, wherein A1 and A2 in the general formula (I) are hydrogen atoms.

3. A silver halide photographic material as in Claim 1 or 2, wherein G in the general formula (I) is a carbonyl group.

4. A silver halide photographic material as in Claim 1, 2 or 3, wherein R1 is substituted with an alkyl, aralkyl, alkoxy, aryl, substituted amino, acylamino, sulfonylamino, ureido, urethane, aryloxy, sulfamoyl, carbamoyl, alkylthio, arylthio, sulfonyl, sulfinyl, hydroxyl, cyano, sulfo or carboxyl group or a halogen atom.

5. A silver halide photographic material as claimed in any preceding claim, wherein R1 or R2 includes a group X1 QL1Xm wherein X1 is a group which promotes adsorption of the compound (I) onto silver halide grains, L1 is a linking group and m is 0 or 1.

6. A silver halide photographic material as claimed in Claim 5, wherein X1 is a thioamido, mercapto or 5or 6-membered nitrogen-containing heterocyclic group.

7. A silver halide photographic material as claimed in any preceding claim, wherein R1 is an aromatic group.

8. A silver halide photographic material as claimed in Claim 7, wherein the hydrazine compound of the formula (I) is represented by the general formula (II):

wherein Y1 is a substituent group as defined in Claim 4 or is said substituent group which can be dissociated to an anion of a pKa value of at least 6; n has a value of 0, 1 or 2; R4 is the same as R1 in Claim 1, or represents a 4 XX group as defined in Claim 5 or 6.

9. A silver halide photographic material as in Claim 8, wherein the R4SO2NH group is substituted in the position para to the acylhydrazino group.

10. A silver halide photographic material as claimed in any preceding claim, wherein R1 contains a ballast group.

11. A silver halide photographic material as claimed in Claim 1, wherein the compound of formula (I) is any of the compounds (1) to (40) shown hereinbefore.

12. A silver halide photographic material as in any preceding claim, wherein the compound represented by the general formula (I) is included in a silver halide emulsion layer of the material.

13. A silver halide photographic material as in any preceding claim, wherein the compound of general formula (I) is contained in an amount of from 10 6 to 1 x 10 1 mol per mol of silver halide.

14. A silver halide photographic material as in Claim 13, wherein said amount of the compound of general formula (I) is 10~5 to 4 x 10-2 mol per mol of silver halide.

15. A silver halide photographic material as in any preceding claim, wherein the rhodium salt is a watersoluble halogen compound of trivalent rhodium.

16. A silver halide photographic material as in any preceding claim, wherein the rhodium salt is present in an-amount of from 1.0 x 10 5 to 1.0 x 10 3 mol per mol of silver halide.

17. A silver halide photographic material as in Claim 16, wherein said amount of rhodium salt is 5.0 x 10 5 to 5.0 x 10 4 mol per mol of silver halide.

18. A silver halide photographic material as claimed in any preceding claim, which also contains an organic desensitising agent.

19. A silver halide photographic material as claimed in Claim 18, wherein said agent has at least one watersoluble or water-dissociable group.

20. A silver halide photographic material as claimed in Claim 1,%substantially as hereinbefore described with reference to any of the samples Nos. 1-14 of the Examples.

21. A silver halide photographic material as in any preceding claim, wherein the mean grain size of the core portions of the silver halide grains is from 0.01 urn to 0.12 urn.

22. A silver halide photographic material as in claim 21, wherein said mean grain size is from 0.02 urn to 0.08 urn.

23. A silver halide photographic material as in any preceding claim, wherein the mean grain size of the silver halide grains is not larger than 0.15 urn.

24. A silver halide photographic material as in Claim 23, wherein said mean grain size is from 0.05 um to 0.12 urn.

25. A silver halide photographic material as in any preceding claim, wherein the rhodium content of the core portions of the silver halide grains is 1.0 x 10-6 tb 5 x 10-5 mol per mol of silver.

26. A silver halide photographic material as in any preceding claim1 wherein the rhodium content of the shell portions of the silver halide grains is 1.0 x 10-5 to 5 x 10-4 mol per mol of silver.