GB2202341A - Silver halide super high contrast negative photographic material - Google Patents

Abstract

Silver halide photographic material comprises a support having thereon at least one layer of silver halide emulsion containing a water-soluble rhodium salt, preferably of a halogen complex, at a concentration of at least 10<-5> mol per mol of silver halide: and a hydrazine compound of the general formula (I> <IMAGE> wherein A1 and A2 both represent hydrogen or one of them represents hydrogen and the other a sulfinic acid residual group or acyl group; R1 represents an optionally substituted aliphatic, aromatic (preferred) or heterocyclic group preferably containing a ballast group; R2 represents hydrogen or an optionally substituted alkyl, aryl, alkoxy, aryloxy or amino group; and G a carbonyl (preferred), sulfonyl, sulfoxy, phosphoryl or iminomethylene group, and 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 R1 or R2 may include a heterocyclic group for promoting adsorption of the hydrazone onto AgX grains. 40 of the compounds (I) are listed, and syntheses exemplified. Organic desensitizers and/or water-soluble dyes may be included in the material. The photographic material is imagewise exposed, and subsequently developed with a developing solution containing sufite ions in an amount of at least 0.15 mol per litre and having a pH of 10.5 to 12.3 to give negative images of enhanced contrast.

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, andmore precisely to photographic materials which can be handled in a bright ro̲m (hereinafter r.eferred-to as bright room-type silver halide photographic materials" ) ,- - 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. Patent Nos. 4,224,401, 4,168,977, 4,166,742, 4,311,781, 4,272,606, 4,211,857 and 4,243,739 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 6f high concentrations of sulfite can be tolerated in the developer and so the stability of the developer in respect of aerial oxidation in much better than that of a lith developer.

However, the above mentioned image forming systems are applicable to high speed enhanced contrast systems and it is difficult to obtain low sensitivity bright room-type photographic materials in this way. Silver halide photographic materials in which water - soluble rhodium salts are contained in a contrast -enhancing system in which hydrazine derivatives are used have been suggested for example in Japanese Patent Applications (OPI) Nos.

83038/85 and 162246/85 (the term "OPI" as used herein means a published unexamined Japanese patent applica tion-) as a method of obtaining low sensitivity bright room-type photographic materials. However, if an amount of rhodium sufficient to lower the sensitivity is added, the enhancement of contrast by the hydrazine derivative cannot be achieved and the prescribed high contrast image is not obtained.

More precisely, for a silver halide emulsion which contains more than 1.0x10-5 mol of rhodium per mol of silver, there is a marked reduction in contrast with the conventionally known hydrazine derivatives.

Bright room-type photographic materials as described in this patent means photographic materials which can be used safely for long periods of time in light of long wavelengths (essentially not shorter than 400 nm) which does not contain an ultraviolet component as a safe light.

As a result of thorough research, the inventors have overcome these problems and provided bright room-type photographic materials with which contrast enhancement can be achieved using hydrazine compounds.

The above mentioned object of the invention has been attained by providing a superhigh contrast negative type silver halide photographic material which comprises a support having thereon at least one silver halide emulsion layer, the silver halide emulsion layer or at least one other hydrophilic colloid layer of the material containing a hydrazine compound represented by the general formula (I) below, and the silver halide emulsion layer containing a water soluble rhodium salt at a concentration of at least 10-5 mol per mol of silver halide::

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 aliphatic group, an aromatic group or a heterocyclic group, R2 represents a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group or an 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 10.5 to 12.3.

The hydrazine canpounds - ed 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, aryl 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 a hydrogen atom, alkyl groups (for example, methyl group, trifluoromethyl group, 3hydroxypropyl group, 3-methanesulfonamidopropyl group, etc.), aralkyl groups (for example, o-hydroxybenzyl group, etc.) and aryl groups (for example, phenyl group, 3,5dichlorophenyl group, o-methanesulfonamidophenyl group, 4methanesulfonylphenyl group,), 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, etc.), an aralkyl group (for example, an o-hydroxyphenylmethyl group etc.), an aryl group (for example, a phenyl group, etc.) or a substituted amino group (for example, a dimethylamino group,).

When G is a sulfoxy group, the preferred R2 groups are cyanobenzyl 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 alkyl groups, phenyl groups, ether groups, amido groups, ureido groups, urethane groups, sulfonamide groups. or thioether groups . having at least 8 carbon atoms.

R1 or R2 may have a group XltLltm 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 X1 are thioamido groups, mercapto groups and five or six membered nitrogen-containing heterocyclic groups.

The thioamido adsorption promoters 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. Patents 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-ring like thioamido groups include thioureido groups, thiourethane groups and dithiocarbamic acid ester groups,-- and actual examples of ring-like thioamido groups include 4-thiazolin-2thione, 4-imidazolin-2-thione, 2-thiohydantoin, rhodanine, thiobarbituric acid, tetrazolin-5-thione, 1,2,4-triazolin3-thione, 1,3,4-thiadiazolin-2-thione, 1,3,4-oxadiazolin2-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, etc. 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 nitrogen-containing 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=, 1-CO-- and 502 (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 benzol 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 acids 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 (for example -CH2COOC2H5, -CH2COCH3,

etc.), etc.

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 L1mX1 group and it is preferably a tli::mXi 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.

Typical methods for the synthesis of compounds represented by the general formula (I) mentioned above are described below. Moreover the compounds of this invention can be synthesized with reference to the methods disclosed, for example, in Japanese Patent Applications (OPI) Nos. 67843/81 and 179734/85.

Example of Synthesis 1 Synthesis of Compound (1) 2-(4-Aminophenyl)-l-formylhydrazine (2.5 grams) was dissolved under a blanket of nitrogen in 10 ml of N,Ndimethylformamide, 2.1 ml of triethylamine was added and the solution was cooled to -50C. Next a solution obtained by dissolving 5.8 grams of 4-(2,4-di-tert-pentylphenoxy)l-butylsulfonyl chloride in 10 ml of acetonitrile was drip fed into the above mentioned solution. The mixture was stirred while cooling in such a way that the temperature did not rise above OOC during the addition. The mixture was subsequently stirred for a further period of 1 hour at OOC and then poured into ice water and extracted with ethyl acetate. The organic layer was washed with saturated salt water, dried over anhydrous sodium sulfate and filtered and the filtrate was concentrated.The concentrate was then separated and refined using silica gel column chromatography (eluting solvent: ethyl acetate/chloroform=2/1 (vol/vol)) and the target substance was obtained. Yield 2.7 grams, an oily substance.

Synthesis Example 2 Synthesis of Compound (10) 2-(1) Synthesis of 2-[4-(3-Nitrobenzenesulfonamido) phenyl ] -l-formylhydrazine One liter of N,N-dimethylacetamide, 880 ml of acetonitrile and 285 grams of triethylamine were added to 426 grams of 2-(4-aminophenyl)-1-formylhydrazine under a blanket of nitrogen to form a solution and, after cooling to -50C, 625 grams of m-nitrobenzenesulfonyl chloride was added gradually. During this time the mixture was stirred while cooling in such a way that the liquid temperature did not exceed -50C. The mixture was subsequently stirred at a temperature below -50C for a period of 1.5 hours and then raised to room temperature and extracted with 12 liters of ethyl acetate and 12 liters of saturated salt water.The organic layer was recovered and concentrated to 6 liters, after which 3 liters of n-hexane was added and the crystals which had been formed after stirring at room temperature for 30 minutes were recovered by filtration and washed with 500 ml of ethyl acetate. Yield 680 grams, Melting point 191-1930C.

2-(2) Synthesis of 2- [ 4-(3-Aminobenzenesulfonamido) phenyl ] -l-formylhydrazine Iron powder (680 grams), 68 grams of ammonium chloride, 6.5 liters of isopropanol and 2.2 liters of water were mixed together and heated with stirring on a steam bath. The nitro compound obtained in 2-(1) above (680 grams) was added to this mixture and refluxed for a period of 1.5 hours. The insoluble material was then removed by filtration, the filtrate was concentrated under reduced pressure and water was added. The crystals which formed were recovered by filtration and washed with 1 liter of isopropanol. Yield 535 grams, Melting point 1551560C.

2-(3) Synthesis of 2- [ 4-(3-Phenoxycarbonylaminobenzene sulfonamido)phenyl ] -l-formylhydrazine The amino compound obtained in 2-(2) above (450 grams) was dissolved under a blanket of nitrogen in 2.8 liters of N,N-dimethylacetamide and cooled to a temperature below -5 C, 120 ml of pyridine was added and then 230 grams of phenyl chloroformate was drip fed into the mixture. The mixture was stirred while cooling in such a way that the t =ature of the liquid did not exceed -50C during this time. The mixture was stirred for a further period of 1 hour at a temperature below -50C and then the reaction mixture was drip fed into 20 liters saturated salt water and stirred for a period of 30 minutes. The crystals which formed were recovered by filtration and washed with 2 liters of water. Yield 611 grams, Melting point 195-1970C 2-(4) Synthesis of Compound (10) 3-( 2,4-di-tert-pentylphenoxy)-l-propylamine (32 grams) and 15 grams of imidazole were dissolved under a blanket of nitrogen in 30 ml of acetonitrile and heated to 500C. A solution obtained by dissolving the urethane compound obtained in 2-(3) above (42.6 grams) in 40 ml of N,N-dimethylacetamide was drip fed into this solution and the mixture was heated to 500C for a period of 1.5 hours with stirring. The mixture was then cooled to 300C, after which it was poured into a mixture consisting of 1 liter of 0.5 mol/liter hydrochloric acid and 1 liter of ethyl acetate. The organic layer was separated and concentrated and then recrystallized from an ethyl acetate/n-hexane solvent mixture (vol/vol=2/5).Yield 33.6 grams, Melting point 118-1210C (softening) Example of Synthesis 3 Synthesis of Compound (38) 2-(4-aminopheny1)-l-acety1hydrazine (2.5 grams) was dissolved under a blanket of nitrogen in 10 ml of N,Ndimethylformamide, 2.1 ml of triethylamine was added and the mixture was cooled to -5 0C. A solution obtained by dissolving 5.8 grams 4-(2,4-di-tert-pentylphenylphenoxy)l-butylsulfonyl chloride in 10 m1 of acetonitrile was drip fed into this solution. The mixture was stirred while cooling in such a way that the liquid temperature did not exceed Doc during this time. The mixture was stirred for a further period of 1 hour at OOC and then poured into ice water and extracted with ethyl acetate.The organic layer was washed with saturated salt water, dried over anhydrous sodium sulfate and filtered and then the filtrate was concentrated. The concentrate was separated and refined by silica gel column chromatography (eluting solvent: ethyl acetate/chloroform=2/1 (vol/vol)) and the target compound was obtained. Yield 3.2 grams, Oily material.

Example of Synthesis 4 Synthesis of Compound (39) 2-(3-Aminophenyl)-l-formylhydrazine (10.6 grams) was dissolved under a blanket of nitrogen in 30 ml of N,Ndimethylformamide, 8.2 ml of triethylamine was added and the mixture was cooled to -50C. A solution obtained by dissolving 11.3 grams of 4-(2,4-di-tert-pentylphenylphenoxy)-l-butylsulfonyl chloride in 20 ml of acetonitrile was drip fed into this solution. The mixture was stirred while cooling in such a way that the liquid temperature did not exceed OOC during this time. The mixture was stirred for a further period of 1 hour at OOC and then poured into ice water and extracted with ethyl acetate.

The organic layer was washed with saturated salt water, dried over anhydrous sodium sulfate and filtered and then the filtrate ;was concentrated. The concentrate was separated and refined by silica gel column chromatography (eluting solvent: ethyl acetate/chloroform=2/1 (vol/vol)) and the target compound was obtained. Yield 12.2 grams, Solid material Example of Synthesis 5 Synthesis of Compound (2) 5-(1) Synthesis of 1-(2-Chloro-4-nitrophenyl)hydrazine Hydrazine hydrate (59 ml) was dissolved under a blanket of nitrogen in 712 ml of acetonitrile and a solution obtained by dissolving 46.3 grams of 1,2 dichloro-4-nitrobenzene in 71 ml of acetonitrile was added dropwise. After completing the dropwise addition, the mixture was heated under reflux for a period of 4 hours and then the reaction mixture was concentrated.The crystals obtained on adding 500 ml of water were recovered by filtration, 200 ml of acetonitrile was added and the mixture was heated under reflux for 30 minutes, after which the mixture was cooled to room temperature and the crystals were recovered by filtration. Yield 27 grams 5-(2) Synthesis of 2-(2-Chloro-4-nitrophenyl)-l- formylhydrazine The hydrazine compound obtained in 5-(1) above (27 grams) was dissolved under a blanket of nitrogen in 160 ml of acetonitrile and 14 ml of formic acid was added dropwise. The mixture was subsequently heated under reflux for a period of 2 hours and cooled with ice and the crystals which formed were recovered by filtration and washed in acetonitrile.Yield 20.3"grams 5-(3) Synthesis of 2- ( 4-Amino-2-chlorophenyl ) -1-formyl- hydrazine The nitro compound obtained in 5-(2) above (19.5 grams), 20 grams of iron powder, 2 grams of ammonium chloride, 400 ml of isopropanol and 20 ml of water were mixed together under a blanket of nitrogen and stirred under reflux for 2 hours on a steam bath. The insoluble materials were removed by filtration while the mixture was hot and the filtrate was concentrated under reduced pressure to about 200 ml sand cooled. The crystals which formed were recovered by filtration and washed with 200 ml of isopropanol.Yield 11.0 grams 5-(4) Synthesis of Compound (2) 2- ( 4-Amino-2-chlorophenyl) -1-formylhydrazine (5.55 grams) was dissolved under a blanket of nitrogen in 30 ml of N,N-dimethylformamide, 3.03 grams of triethylamine was added and the mixture was cooled to -50C. A solution obtained by dissolving 11.8 grams of 4-(2,4-di-tertpentylphenoxy)-l-butylsulfonyl chloride in 10 ml of acetonitrile was drip fed into the mixture. The mixture was stirred with cooling so that the liquid temperature did not exceed OOC during this time. The mixture was subsequently stirred for a period of 1 hour at OOC and then poured into ice water and extracted with ethyl acetate. The organic layer was washed with saturated salt water, dried over anhydrous sodium sulfate and filtered and the filtrate was concentrated.The concentrate was separated and refined by silica gel column chromatography (eluting solvent: ethyl acetate/chloroform=l/2 (vol/vol)) and the target material was obtained. Yield 7.0 grams, Melting point 157-1590C.

Example of Synthesis 6 Synthesis of Compound (37) 6-(1) Synthesis of 2-Chloro-l-diethylsulfamoyl-5-nitro benzene 2-Chloro-5-nitrophenylsulfonyl chloride (7.6 grams) was dissolved in 50 ml of acetone, cooled to -l00C and a solution obtained by dissolving 3.03 grams of triethylamine and 2.2 grams of diethylamine in 20 ml of acetonitrile was added dropwise. The mixture was stirred while cooling in such a way that the liquid temperature did not exceed OOC during this time. The temperature was gradually raised to room temperature and the mixture was poured into dilute aqueous hydrochloric acid of pH about 2. The crystals which formed were recovered by filtration and washed with water. Yield 7.8 grams 6-(2) Synthesis of l-( 2-Diethylsulfamoyl-4-nitrophenyl)- hydrazine The chloro derivative obtained in 6-(1) above (7.0 grams) was dissolved in 90 ml of methanol and heated under reflux and a solution obtained by dissolving 6.2 ml of hydrazine hydrate in 30 ml of ethanol was drip fed into the mixture. The mixture was refiuxed for 4 hours, and then concentrated to obtain the target material. Yield 7.8 grams 6-(3) Synthesis of 2-(2-Diethylsulfamoyl-4-nitrophenyl)- l-formylhydrazine The hydrazine compound in 6-(2) above (5 grams) was dissolved under a blanket of nitrogen in 25 ml of acetonitrile and 2 ml of formic acid was added dropwise.

The mixture was heated under reflux for 5 hours and then concentrated under reduced pressure, 100 ml of water was added and the mixture was stirred for a period of 1 hour at room temperature. The crystals which formed were recovered by filtration and recrystallized from ethanol.

Yield 4.0 grams 6-(4) Synthesis of 2-(4-Amino-2-diethylsulfamoylphenyl) l-formylhydrazine The nitro compound obtained in 6-(3) above (10 grams) was dissolved under a blanket of nitrogen in 210 ml of ethanol and 90 ml of water and a solution obtained by dissolving 27 grams of hydrosulfite in 120 ml of water was drip fed into this solution. The mixture was stirred at room temperature for a period of 30 minutes and for 15 minutes at a temperature of 600C. The insoluble materials were removed by filtration, after which the filtrate was concentrated under reduced pressure, 100 ml of water was added and the crystals which formed were removed by filtration and recrystallized from ethanol.Yield 3.7 grams 6-(5) Synthesis of Compound (37) The amino compound obtained in 6-(4) above (1.7 grams) was dissolved under a blanket of nitrogen in 17 ml of acetonitrile and heated under reflux and a solution obtained by dissolving 2.8 grams of 4-(2,4-di-tertpentylphenoxy)-l-butylsulfonyl chloride in 2.8 ml of acetonitrile was added dropwise. The mixture was heated under reflux for a period of 1 hour and then poured into 200 ml of water. The supernatant liquid was removed and the mixture solidified on adding n-hexane. The target material was obtained by removing the supernatant n-hexane and washing with ether.Yield 1.4 grams, Melting Point 169-1710C Example of Synthesis 7 Synthesis of Compound (21) 7-(1) Synthesis of 2-[4-(3-Nitrobenzenesulfonamido) phenyl ] -l-formylhydrazine 2- ( 4-Aminophenyl) -l-formylhydrazine (426 grams) was dissolved under a blanket of nitrogen in 1 liter of N,N-dimethylacetamide and 880 ml of acetonitrile with the addition of 285 grams of triethylamine and, after cooling to -50C, 625 grams of m-nitrobenzenesulfonyl chloride was added gradually. The mixture was stirred while cooling in such a way that the liquid temperature did not exceed -50C during this time. The mixture was stirred for a further period of 1.5 hours at temperatures below -50C and then warmed to room temperature and extracted with 12 liters of ethyl acetate and 12 liters of saturated salt water.The organic layer was separated and concentrated to 6 liters, after which 3 liters of n-hexane was added and the crystals which formed on stirring at room temperature over a period of 30 minutes were recovered by filtration and washed with 500 ml of ethyl acetate. Yield 680 grams, Melting Point 191-1930C 7-(2) Synthesis of 2-[4-(3-aminobenzenesulfonamide) phenyl ] -l-formylhydrazine Iron powder (680 grams), 68 grams of ammonium chloride, 6.5 liters of isopropanol and 2.2 liters of water were mixed together and heated with stirring on a steam bath. The nitro compound obtained in 7-(1) above (680 grams) was added and the mixture was refluxed for a period of 1.5 hours. The insoluble material was then removed by filtration, the filtrate was concentrated under reduced pressure and water was added.The crystals which formed were recovered by filtration and washed with 1 liter of isopropanol. Yield 535 grams, Melting Point 1551560C.

7-(3) Synthesis of 2- [ 4-(3-Phenoxycarbonylaminobenzene- sulfonamide)phenyl ] -l-formylhydrazine The amino compound obtained in 7-(2) above (450 grams) w,as dissolved under a blanket of nitrogen in 2.8 liters of N,N-dimethylacetamide and cooled to -5 C, 120 ml of pyridine was added and 230 grams of phenyl chloroformate was added dropwise. The mixture was stirred with cooling in such a way that the liquid temperature did not exceed -50C during this time. The mixture was stirred for a further period of 1 hour at temperatures below -50C and then dripped into 20 liters of saturated I salt water and stirred for a period of 30 minutes. The crystals which formed were recovered by filtration and washed with 2 liters of water.Yield 611 grams, Melting Point 195 l970C.

7-(4) Synthesis of Compound (21) l-(3-aminophenyl)-5-mercaptotetrazole hydrochloride (5.93 grams) and 7.03 grams of imidazole were dissolved under a blanket of nitrogen in 30 ml of acetonitrile and heated to 650C. A solution obtained by dissolving 10 grams of the urethane compound obtained in 7-(3) above in 58 ml of N,N-dimethylacetamide was drip fed into this solution and heated at 650C for a period of 1.5 hours with stirring. After cooling to 300C the reaction mixture was extracted with 240 ml of ethyl acetate and 240 ml of water and the aqueous layer was poured into dilute aqueous hydrochloric acid. The crystals which formed were recovered by filtration and washed with water.Yield 8.2 grams, Melting Point 205-2070C (with decomposition) Example of Synthesis 8 Synthesis of Compound (40) 8-(1) Synthesis of 2- [ 4-(2-Chloro-5-nitrobenzenesulfon amido)phenyl ] -l-formylhydrazine 2-(4-aminophenyl)-l-fomylhydrazine (35.4 grams) was dissolved under a blanket of nitrogen by adding 90 ml of N,N-dimethylacetamide, 76 ml of acetonitrile and 19 ml of pyridine and, after cooling to -5 C, 59.9 grams of 2chloro-5-nitrobenzenesulfonyl chloride was added gradually. The mixture was stirred and cooled in such a way that the temperature did not exceed -50C during this time. The mixture was stirred for a further period of 1.5 hours at temperatures below -50C and then warmed to room temperature and poured into 1 liter of saturated salt water. The crystals which formed were recovered by filtration and washed with water.Yield 63 grams 8-(2) Synthesis of 2- [ 4-(5-Amino-2-chlorobenzenesulfon amido)phenyl ] -l-formylhydrazine Iron powder (30.1 grams), 4.5 grams of ammonium chloride, 930 ml of dioxane and 400 ml of water were mixed together and heated with stirring on a steam bath. The nitro compound obtained in 8-(1) above (50 grams) was added and the mixture was refluxed for a period of 1.5 hours. The insoluble material was removed by filtration and the filtrate was concentrated under reduced pressure and then extracted with ethyl acetate and saturated salt water and the organic layer was concentrated under reduced pressure. Yield 43 grams, Oily material 8-( 3) Synthesis of l-( 3-Phenoxya'midophenyl)-5-mercapto- tetrazole l-(3-Aminophenyl)-5-mercaptotetrazole hydrochloride (390.5 grams) was dissolved under a blanket of nitrogen in 800 ml of N,N-dimethylacetamide and after adding 302 ml of pyridine dropwise, the mixture was cooled to below OOC and 235 ml of phenyl chloroformate was added dropwise. The mixture was stirred and cooled in such a way that the temperature did not exceed OOC during this time. After stirring at temperature below OOC for a period of 30 minutes the temperature was raised to room temperature and the reaction mixture was stirred for a further period of 3 hours.The mixture was then cooled to below 100C, 500 ml of isopropanol and 5 liters of water were added and the crystals subsequently obtained were recovered by filtration and washed with water. Yield 495 grams, Melting Point 190-1910C 8-(4) Synthesis of Compound (40) The amino compound obtained in 8-(2) (6.5 grams) and 5.4 grams of the urethane compound obtained in 8-(3) were dissolved under a blanket of nitrogen in 35 ml of N,N-dimethylacetamide and 6.1 ml of N-methylmorpholine was added. The mixture was stirred at 500C for a period of 7 hours and then cooled to room temperature and poured into 30 ml of dilute hydrochloric acid. The crystals which formed were recovered by filtration and washed with water.

Yield 6.2 grams, Melting Point 160-1650C (with decomposition) Example of Synthesis 9 Synthesis of Compound (17) N,N-dimethylformamide (10 ml) was drip fed into a solution of 10 grams of 3-(5-mercaptotetrazoyl)phenylsulfonic acid sodium salt (10 grams) and 7 ml of thionyl chloride while stirring and cooling in ice, the temperature was gradually raised to room temperature and the mixture was stirred at this temperature for a period of 2 hours. The excess thionyl chloride was removed from the reaction mixture by distillation under reduced pressure.The residual liquid so obtained was poured into ice water, extracted twice with chloroform and on concentration after drying over anhydrous magnesium sulfate, 3.5 grams of 3-(5-mercaptotetrazoyl)phenylsulfonyl chloride was obtained as a colorless oily substance. (Yield 36%.) Next, 1.4 ml of pyridine was added with ice cooling and under a blanket of nitrogen to a solution of 2.2 grams of l-formyl-2-(4-aminophenyl)hydrazine in 10 ml of N,N-dimethylformamide, 5 ml of acetonitrile containing 3.5 grams of 3-(5-mercaptotetrazolyl)phenylsulfonyl chloride was added dropwise and the mixture was stirred with ice cooling for a period of 1 hour. The reaction mixture was then poured into a solution consisting of 3 ml of hydrochloric acid and 100 ml of water and the crystals which precipitated out were recovered by filtration.The crystals so obtained were recrystallized from isopropyl alcohol whereupon 4.4 grams of l-(3- [ 4-(2-formyl- hydrazino)pheny1su1famoy1)phenyl-5-mercaptotetrazole was obtained. Yield 77%, Melting Point l920C (with decomposition) The - compound represented by the general formula (I) is included in the 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) of 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 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 of this invention represented by the general formula (I) can be used cojointly with the hydrazine compounds which were used in the past. Various hydrazine compounds can be used conjointly and examples of such compounds are disclosed in Japanese Patent Applications (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).

The silver halide emulsion which is used in the invention may have any composition, such as silver chloride, silver chlorobromide, silver iodobromide, silver iodochlorobromide, etc. but a silver halide which has a silver chloride content of at least 60 mol% and preferably of at least 75 mol% is preferred. The use of silver chlorobromide or silver chloroiodobromide which contains from 0 to 5 mol of silver bromide is preferred.

The average grain size of the silver halide which is used in the invention is preferably very fine (for example not larger than 0.7 pm) and an average grain size of not larger than 0.5 pm is especially desirable. No fundamental limitation is imposed upon the grain size distribution but mono-dispersions are preferred. In this connection, a mono-dispersion signifies that the material consists of grains of which in terms of weight or numbers of grains 95% have a size within +40% of the average grain size.

The silver halide grains in the photographic emulsion may have a regular crystal form such as a cubic or octahedral form or they may have an irregular crystal form such as spherical or tabular form or alternatively they may have a complex form consisting of these crystal forms.

The silver halide grains may be such that the interior and surface layers consist of a uniform phase or of different phases. Mixtures of two or more types of silver halide emulsion which have been prepared separately can also be used.

A rhodium salt or a complex salt thereof is also present in the silver halide emulsion used in the invention.

The rhodium salt may be rhodium monochloride, rhodium dichloride, rhodium trichloride, ammonium hexachlororhodinate, etc., but a water-soluble halogen complex compound of trivalent rhodium, for example, hexachloro rhodium (III) acid or salts thereof (ammonium salt, sodium salt, potassium salt, etc.) are preferred.

The amount of these water-soluble rhodium salts added is within the range from 1.0x10-5 mol to 1.0x10-3 mol per mol of silver halide. The preferred amount is between 5.0x10-5 mol and 5.0x10-4 mol.

If the amount of rhodium salt used is greater than 10-3 mol, it is impossible to achieve adequate enhancement of contrast. Conversely if the amount used is less than 10-5 mol, it is not possible to achieve a suitable lowering of sensitivity for a bright room-type photographic material.

The addition of the rhodium salt may take place during the formation of the silver halide grains in the manufacture of the silver halide emulsion or during the physical ripening process.

Cadmium salts, sulfites, lead salts, thallium salts and iridium salta can also be present along with the rhodium salts.

The silver halide photographic materials of this invention may contain organic desensitizing agents. The organic desensitizing agents which have at least one watersoluble 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, etc.) or an alkali metal (for example, sodium, potassium, etc.), etc.

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, sulfonamido 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 indicated below.

The organic desensitizing agents are preferably included at a rate of 1.0x10-8 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 photographic 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 relation . with the support, depending on the intended purpose of the dyes.

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 gram/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 derivative; 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 (l,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, 5methyl-benzotriazole) 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, 1,3-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.

Various compounds which contain nitrogen or sulfur atoms are effective as well as the compounds disclosed in Japanese Patent Applications (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.

n-C4H9N (C2H4OH)2 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 accelerators 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 l-phenyl-3pyrazolidone, 4,4-dimethyl-1-phenyl-3-pyrazolidone), aminophenols (for example N-methyl-p-aminophenol) 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 180C 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-p-aminophenol hemisulfate 0.8 grams Sodium hydroxide 18.0 grams Potassium hydroxide 55.0 grams 5-Sulfosalicylic acid 45.0 grams Boric acid 25.0 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 n-Butyldiethanolamine 15.0 grams Water to make 1 liter (pH=1l.6) COMPARATIVE EXAMPLE 1 Aqueous solutions of silver nitrate and sodium chloride were added simultaneously to an aqueous gelatin solution which was being maintained at a temperature of 400C in the presence of 5.0x10-5 mol of (NH4)3RhC16 per mol of silver, after which the soluble salts were removed using the methods well known in the industry, and then gelatin was added and 2-methyl-4-hydroxy-l,3,3a,7-tetra- azaindene was added as a stabilizer without chemical ripening. This emulsion was a mono-dispersed emulsion of a cubic crystal form in which the average grain size was 0.08 pm.

The hydrazine compound of which the formula is indicated below (as Compound A) was added at the rate of 74 mg/square meter and poly(ethyl acrylate) latex was added in an amount of 30 wt% in terms of the solid fraction relative to the gelatin, 1,3-vinylsulfonyl-2propanol was added as a hardening agent and the mixture was coated in such a way as to provide a weight of silver of 3.8 grams/square meter on a polyester support. The gelatin was coated at the rate of 1.8 grams per square meter. A layer of gelatin was coated at the rate of 1.5 grams/square meter over the top of this layer as a protective layer.

(Compound A)

This sample was exposed through an optical wedge for a bright room, P-607 (manufactured by Dainippon Screen Mfg. Co., Ltd,), developed for 20 seconds at 380C, fixed, washed and dried. This sample was denoted as Comparative Sample a.

The photographic results obtained were as shown in Table 1.

EXAMPLE 1 Samples were prepared in the same way as in Comparative Example 1 except that compounds of this invention were used for the hydrazine compound. The types and amounts of the compounds used were as shown in Table 1.

TABLE 1 Hydrazine compound Photographic Properties Sample No. Type Amount Added Sensitivity* Gamma** (mg/m2) Comparative Sample (a) Compound A 74 0 4.0 Sample (1-1) Compound (1) 37 +0.03 9.3 " (1-2) Compound (7) 14 +0.04 10.3 " (1-3) Compound (8) 10 +0.04 10.7 " (1-4) Compound (12) 34 -0.02 7.5 " (1-5) Compound (21) 9 +0.05 14.0 " (1-6) Compound (23) 25 -0.01 8.0 *Sensitivity: The sensitivity (log E) of the blank (Comparative Sample (a)) was taken as a standard and the diference in sensitivity from this standard is indicated. Hence a value of -1.0 for example has a sensitivity in terms of log E 1.0 lower than that of the blank, which is to say that the sensitivity of the material is lower by a factor of 10 times.

**Gradation (Gamma): This is the gradient of the line joining the point of density 0.3 and 3.0 on the characteristic curve. Thus the contrast increas as the value becomes larger.

It is clear from the results shown in Table 1 that the samples of this invention (Sample Nos. (1-1) to (1-6)) provided a higher contrast than the sample obtained in Comparative Example 1.

EXAMPLE 2 This was the same as Example 1 except that compound (21) was used at the rate of 9 mg/square meter as the hydrazine compound and the following additives were used.

(Nucleation Accelerators)

50 mg/m2 The result was that gamma was raised to 23.0.

EXAMPLE 3 This was carried out in the same way as Example 2 except that the rhodium salt content of the silver chloride emulsion was raised to 1.0x10-4 mol or 1.5x10-4 mol per mol of silver. The results obtained showed that gamma had a high level of 20.3 and 18.4, respectively.

Claims (24)

CLAIMS:

1. A silver halide photographic material which comprises a support having thereon at least one silver halide emulsion layer, the silver halide emulsion layer or at least one other hydrophilic colloid layer of the material containing a hydrazine compound represented by the general formula (I), and the silver halide emulsion layer containing a water-soluble rhodium salt at a concentration of at least 10-5 mol per mol of .silver halide:

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, aronatic group or -heterocyclic group;R2 represents--a hydrogen-atcn or an optionally substituted aky1, aryl,.- - alkoxy group, årEloxy 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 At14mwherein 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 RI 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 a4L1X1 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 -6 -1 (I) is contained in an amount of from 10 6 to 1 x 10 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 mol 5 to 5.0 x 10 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 Examples 1 to 3.

21. A method for forming superhigh-contrast negative images comprising developing an imagewise -exposed silver halide photographic material as claimed in any preceding claim, with a developing solution containing sulfite ions in an amount of at least 0.15 mol per litre and having a pH of 10.5 to 12.3.

22. A method as claimed in Claim 21, wherein said pH is 11.0 to 12.0.

23. A method as claimed in Claim 21 or 22, wherein the development is in a processing bath containing a dihydroxybenzene and a 3-pyrazolidone or an aminophenol.

24. A method as claimed in Claim 21, substantially as hereinbefore described with reference to any of Examples 1-to 3.