DE69032186T2 - Silver halide photographic materials - Google Patents

Description

FIELD OF INVENTION

The invention relates to a silver halide photographic material and, more particularly, to a silver halide photographic material which provides a negative image having high contrast, high sensitivity and satisfactory dot image quality.

BACKGROUND OF THE INVENTION

In the field of photomechanical systems, there is a demand for satisfactory image reproducibility, stable process solutions and simplification in refilling to cope with the recent diversity and complexity of printed materials.

In particular, originals in line work include phototypesetting letters, handwritten letters, illustrations and dot prints, and thus contain images with different densities and line widths. There has therefore been a demand to develop a process camera, a photosensitive photographic material and an image forming system that can reproduce an original with high accuracy. In photomechanical reproduction of catalogs or large posters, enlargement or reduction of a dot print is often required. When a dot print is enlarged in platemaking, the number of lines per inch is reduced and the dots bleed. If a dot print (halftone dot) is reduced, the number of lines per inoh increases and the dots become finer. Accordingly, there has been a demand for an image forming system with a wider exposure latitude to maintain the reproducibility of a halftone gradation.

A halogen lamp or a xenon lamp is used as a light source for a process camera. In order to obtain a photographic sensitivity to these light sources, photographic materials are usually subjected to orthochromatic sensitization. However, orthochromatic materials are susceptible to the influence of chromatic aberration of a lens and therefore suffer from deterioration in image quality. The deterioration is conspicuous if a xenon lamp is used as a light source.

Known systems for meeting the demand for a wide exposure latitude include those in which a silver halidelith photosensitive material comprising silver chlorobromide (containing at least 50% silver chloride) is processed with a hydroquinone developer having an extremely low effective sulfite ion concentration (usually 0.1 mol/L or less). A line or dot image is thereby obtained which has a high contrast and a high density, and in which image areas and non-image areas are clearly distinguishable. In this method, however, development is extremely unstable due to air oxidation due to the low sulfite concentration of the developer. Therefore, various efforts and devices are required to stabilize the development activity, and the processing speed is also very low, thereby reducing the working efficiency.

There is therefore a demand for an image forming system which eliminates the instability for image formation inherent in the above-described lith development system and provides an ultra-high contrast image by using a processing solution having a satisfactory preservation stability. In this connection, a latent surface image type silver halide photographic material has been proposed which contains a specific acylhydrazine compound and is developed with a developing solution having a pH between 11.0 and 12.3 and containing at least 0.15 mol/l of a sulfite preservative. This material exhibits a satisfactory preservation stability for forming an ultra-high contrast negative image having a γ value of over 10 as disclosed in US-A-4,166,742, 4,168,977, 4,221,857, 4,224,401, 4,243,739, 4,272,606 and 4,311,781. This new image forming system is characterized in that silver iodobromide and silver chloroiodobromide as well as silver chlorobromide are applicable thereto, while the ultra-high contrast image forming systems are conventionally applicable only to photographic materials comprising silver chlorobromide having a high silver chlorobromide content.

While the image forming system described above is excellent in terms of the sharpness of halftone dots, process stability, speed and reproducibility of originals, the diversity of printing recently requires further improvement for the reproduction of originals.

In an attempt to improve image quality, a method using a redox compound having a carbonyl group capable of imagewise releasing a development inhibitor has been proposed and is disclosed in JP-A-61-213847 (the term "JP-A" as used herein means a J unexamined published Japanese patent application"). However, the degree of halftone gradation is insufficient even with these compounds.

Therefore, a light-sensitive material is required which, when developed with a stable developer, creates a high-contrast dot image whose tone can be controlled to a large extent.

On the other hand, an improvement in processing efficiency in a layout process and a point-to-point processing (so-called contact work) has been attempted by performing the work in a brighter environment. Accordingly, photosensitive materials for plate making which can be handled in an environment called a bright room and exposure printers for these materials have been developed.

The term light-sensitive material for a bright room as used herein means a light-sensitive material which can be safely handled for a long time with a safe light which does not include an ultraviolet light component and has a wavelength of approximately 400 nm or more.

A light-room photosensitive material which can be used in a layout process and for dot-to-dot processing can be exposed while being in intimate contact with a developed film having a letter or dot image (original) to effect negative-positive conversion or positive-positive conversion. The material must effect negative-positive conversion of a dot image or a line or letter image according to the dot area or the line or letter image width of the original. Furthermore, the tone for the dot image or the line or letter width must be controllable. Light-sensitive materials for contact work in a bright room which meet these requirements have been brought onto the market.

However, if a conventional light-room photosensitive material is processed by a high-tech image conversion technique called superimposed letter image formation by contact work in a bright room, the resulting white letter image has a poor quality compared with that obtained by the technique for point-to-point processing in a dark room using a conventional dark-room photosensitive material.

The formation of the superimposed letter image by contact work is illustrated in detail with reference to the only figure of this specification. A film (2) with a letter or line image shown in black (line original) and a film (4) with a dot image shown in black (dot original) are attached to a transparent or semi-transparent base (1) and (3). The bases (3) and (4) are usually made of polyethylene terephthalate films with a thickness of about 100 µm. The line original and the dot original are superimposed to form an original. The emulsion layer (dashed part) of a photosensitive material (5) for dot-to-dot processing is brought into contact with the dot original (4) and exposed. The exposed photosensitive material is then subjected to development to form a white line image within a dot image.

In forming the superimposed letter image described above, it is important that the negative-positive conversion must be carried out exactly in accordance with the dot area of the dot original and the line width of the line original. As can be seen from the figure, the dot original (4) is in intimate contact with the emulsion layer of the photosensitive material (5). On the other hand, the line original (2) is not directly superimposed on the photosensitive material (5), but the base (3) and the dot original (4) are interposed therebetween. Therefore, if the material (5) is exposed to an amount of exposure sufficient to effect negative-positive conversion exactly to the dot original, the exposure passes through the line original via the base (3) and the dot original (4), causing a reduction in the line width of the transparent line image. This causes a deterioration in the quality of the superimposed letter image.

In order to solve the above-described problem, systems using a hydrazine derivative have been proposed as disclosed in JP-A-62-80640, JP-A-62-235938, JP-A-235939, JP-A-63-104046, JP-A-103235, JP-A-63-296031, JP-A-63-314541 and JP-A-64-13545, but sufficient effects have not been achieved so far, so that further improvements are required.

CONTENT OF THE INVENTION

An object of the invention is to provide a light-sensitive photographic material having a wide exposure latitude in the formation of the line image, and which has an ultra-high contrast (particularly a γ of 10 or more) and a high resolving power.

Another object of the invention is to provide an ultra-high contrast photographic light-sensitive material which satisfactorily reproduces a line image having a high background density (Dmax).

Another object of the invention is to provide an ultra-high contrast photographic light-sensitive material having a wide exposure latitude in dot image formation and which forms excellent dots having a high density, sharp outline and a uniform shape.

This and other objects of the invention are achieved by a silver halide photographic material containing a compound represented by formula (I):

wherein R represents an aliphatic group, an aromatic group or a heterocyclic group; and Z represents an atom group necessary to form a nitrogen-containing heterocyclic aromatic group, wherein the heterocyclic ring is selected from the group consisting of pyrrole, imidazoo, pyrazole, 1,2,3-triazole, 1,2,4-triazole, benzotriazole, tetrazole, thiazoline-2-thione, thiazoline-2-one, oxazoline-2-thione, 2-oxazoline-5-thione, 1,2-thiazoline-5-thione, 1,2-oxazoline-5-one, 1,2-thiazoline-5-one, tetrazolin-2-thione, 1,3,4-thiadiazoline-2-thione, 1,3,4-thiadiazoline-2-one, 1,3,4-oxadiazoline-2-thione, 1,2,4-triazoline-3-thione, dihydropyridine-2-thione, dihydropyridine-2-one, isoindole, indole, indazole, benzimidazole, benzimidazole-2-thione, benzimidazole-2-one, benzoxazoline-2-thione, benzoxazoline-2-one, benzothiazoline-2-thione, benzothiazoline-2-one, purine, pyrazolopyridines and pyrazolopyrimidines, wherein the nitrogen-containing heterocyclic aromatic group represented in formula (I) by

or each substituent on this group is substituted with at least one nitro group, and wherein R contains a ballast group or a group capable of accelerating the adsorption of the compound onto silver halide.

SHORT DESCRIPTION OF THE DRAWING

The figure shows a structure at the time of exposure during the formation of a superimposed letter image by contact work.

DETAILED DESCRIPTION OF THE INVENTION

In formula (I), the aliphatic group represented by R includes a straight-chain, a branched or cyclic alkyl, an alkenyl or an alkynyl group.

The aromatic group represented by R includes a monocyclic or a bicyclic aryl group, for example phenyl and naphthyl groups.

The heterocyclic group (heterocyclic ring) represented by R includes a saturated or unsaturated 3- to 10-membered hetero ring containing at least one nitrogen, oxygen or sulfur atom. The hetero ring may be monocyclic or may be a condensed ring with another aromatic or heterocyclic ring. The hetero ring preferably includes a 5- or 6-membered aromatic heterocyclic group, for example those containing a pyridyl group, an imidazolyl group, a quinolinyl group, a benzimidazolyl group, a pyrimidyl group, a pyrazolyl group, an isoquinolinyl group, a thiazoBlyl group or a benzthiazolyl group.

Preferably R is an aromatic group.

R may have a substituent. Examples of suitable substituents for R include an alkyl group, an aralkyl group, an alkenyl group, an alkynyl group, an alkoxyl group, an aryl group, a substituted amino group, an aryloxy group, a sulfanoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a sulfonyl group, a sulfinyl group, a hydroxyl group, a halogen atom, a cyano group, a sulfo group, a carboxyl group, an alkoyloxycarbonyl group, an aryloxycarbonyl group, an acyl group, an alkoxycarbonyl group, an acyloxy group, a carbonamido group, a sulfonamido group, a nitro group and a group represented by formula (II):

R₁ - L - Y - - (II)

wherein Y represents - -, So₂ or - -, wherein R₃ represents an alkoxy group or an aryloxy group; L represents a single bond, -O-, -S- or - -, wherein R₄ represents a hydrogen atom, an aliphatic group or an aromatic group; and R₁ and R₂, which may be the same or different, each represent a hydrogen atom, an aromatic group, an aliphatic group or a heterocyclic group, or R₁ and R₂ are linked together to form a ring.

R may comprise one or more of the groups represented by formula (II).

In formula (II), the aliphatic group represented by R₁ includes a straight-chain, branched or cyclic alkyl, alkenyl or alkynyl group.

The aromatic group represented by R₁ includes a monocyclic or bicyclic aryl group, for example, phenyl and naphthyl groups.

The heterocyclic group represented by R₁ includes a saturated or unsaturated 3- to 10-membered hetero ring containing at least one nitrogen, oxygen or sulfur atom. The hetero ring may be monocyclic or may form a condensed ring with other aromatic or heterocyclic rings. The hetero ring preferably includes a 5- or 6-membered aromatic heterocyclic group, for example, those containing a pyridyl group, an imidazolyl group, a quinolinyl group, a benzimidazolyl group, a pyrimidyl group, a pyrazolyl group, an isoquinolinyl group, a thiazolyl group or a benzthiazolyl group.

R₁ may have a substituent. Examples of suitable substituents for R₁ include an alkyl group, an aralkyl group, an alkenyl group, an alkynyl group, an alkoxyl group, an aryl group, a substituted amino group, an acylamino group, a sulfonylamino group, a ureido group, a urethane group, an aryloxy group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a sulfonyl group, a sulfinyl group, a hydroxyl group, a halogen atom, a cyano group, a sulfo group, a carboxyl group, an alkyloxycarbonyl group, an aryloxycarbonyl group, an acyl group, an alkoxycarbonyl group, an acyloxy group, a carbonamido group, a sulfonamido group and a nitro group. These substituents may be further substituted and may, if possible, be linked to form a ring.

The aliphatic group represented by R₂ includes a straight chain, branched or cyclic alkyl, alkenyl or alkynyl group.

The aromatic group represented by R2 includes a monocyclic or bicyclic aryl group, for example a phenyl group.

R₂ may bear a substituent as mentioned for R₁.

R₁ and R₂ may, if possible, be linked to form a ring.

R₂ preferably represents a hydrogen atom.

Y preferably represents - - or -SO₂-.

L preferably represents a single bond or - -.

The aliphatic group represented by R₄ includes a straight chain, branched or cyclic alkyl, alkenyl or alkynyl group.

The aromatic group represented by R4 includes a monocyclic or bicyclic aryl group, for example a phenyl group.

R₄ may bear a substituent as mentioned for R₁.

R₄ preferably represents a hydrogen atom.

R in formula (I1) may have a substituent containing a group which accelerates adsorption onto silver halide (hereinafter referred to as the adsorption accelerating group).

The adsorption accelerating group with which R may be substituted is represented by the formula x(L')t wherein X represents an adsorption accelerating group; L' represents a divalent linking group and t represents 0 or 1.

Examples of suitable adsorption-accelerating groups represented by X include a thioamido group, a mercapto group, a group having a disulfide linkage, and a 5- or 6-membered nitrogen-containing heterocyclic group.

The adsorption accelerating

Thioamido group is a divalent group represented by - -amino, which forms part of a cyclic structure or an acyclic thioamido group. Useful adsorption accelerating groups can be selected from those disclosed in US-A-4,030,925, 4,031,127, 4,080,207, 4,245,037, 4,255,511, 4,266,013 and 4,276,364 and Research Disclosure, Vol. 151, No. 15162 (Nov. 1976) and ibid., Vol. 176, No. 17626 (Dec. 1978).

Specific examples of acyclic thioamido groups are thioureido, thiourethane and dithiocarbamine ester groups. Specific examples of cyclic thioamido groups are 4-thiazoline-2-thione, 4-imidazoline-2-thione, 2-thiohydantoin, rhodanine, thiobarbituric acid, tetrazoline-5-thione, 1,2,4-triazoline-3-thione, 1,3,4-thiadiazoline-3-thione, 1,3,4-xadiazoline-2-thione, benzimidazoline-2-thione, benzoxazoline-2-thione and benzothiazoline-2-thione. These groups can be further substituted.

The mercapto group represented by X includes an aliphatic mercapto group, an aromatic mercapto group and a heterocyclic mercapto group. A heterocyclic mercapto group in which the carbon to which -SH is bonded is adjacent to a nitrogen atom is the same as a cyclic thioamido group, which is a tautomeric isomer of such a heterocyclic mercapto group.

Specific examples of such a group are the same as mentioned above regarding the cyclic thioamido group.

The 5- or 6-membered nitrogen-containing heterocyclic group represented by X includes those composed of at least one carbon atom and at least one atom selected from nitrogen, oxygen, sulfur atoms. Examples of preferred groups are benzotriazole, triazole, tetrazole, indazole, benzimidazole, imidazole, benzothiazole, thiazole, benzoxazole, oxazole, thiadiazole, oxadiazole and triazine. These groups may be further substituted with a suitable substituent. Substituents include those mentioned with respect to X.

Preferred groups represented by X are a cyclic thioamido group (i.e. a mercapto-substituted nitrogen-containing heterocyclic group, for example 2-mercaptothiadiazole, 3-mercapto-1,2,4-triazole, 5-mercaptotetrazole, 2- mercapto-1,3,4-oxadiazole and 2-mercaptobenzoxazole groups) and nitrogen-containing heterocyclic group (for example benzotriazole, benzimidazole and indazole groups)

X(L')t can carry two or more substituents, which can be the same or different.

The divalent linking group represented by L' is an atom or a group of atoms containing at least one carbon, nitrogen, sulfur and oxygen atom. Examples of L' include an alkylene group, an alkenylene group, an alkynyl group, an arylene group, -O-, -S-, -NH-, -N=, -CO-, -SO₂-, etc., either alone or in combination thereof. These groups may have a substituent.

Specific examples of the linking group L' are -CONH-, -NHCONH-, -SO₂NH-, -COO-, -NHCOO-,

These divalent groups may further carry a substituent selected from those mentioned with respect to the substituents for R.

R may further contain a ballast group, which is commonly used for immobile photographic additives such as couplers.

A ballast group is an organic group which has a sufficiently large molecular weight to substantially prevent the diffusion of a compound represented by formula (I) into other layers or processing solutions. It comprises at least one group selected from an alkyl group, an aryl group, a heterocyclic group, an ether group, a thioether group, an amido group, a ureido group, a urethane group and a sulfonamido group. Preferred ballast groups are those which carry a substituted benzene ring and in particular those which carry a benzene ring which is substituted by a branched alkyl group.

In formula (I), the

shown

heterocyclic aromatic group preferably a substituted or unsubstituted 5- or 6-membered ring, either monocyclic or linked to other rings.

Typical examples of preferred heterocyclic aromatic rings include, for example, pyrrole, imidazole, pyrazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, thiazoline-2-thione, thiazoline-2-one, oxazoline-2-thione, oxazoline-2-one, imidazoline-2-thione, imidazoline-2-one, 1,2-oxazoline-5-thione, 1,2-thiazoline-5-thione, 1,2-oxazoline-5-one,1,2-thiozolin-5-one, tetrazolin-5-thione, 1,3,4-thiadiazoline-2-thione, 1,3,4-thiadiazolin-3-one, 1,3,4-oxadiazoline-2-thione, 1,3,4-oxadiazoline-2-one, 1,2,4-Triazolin-3-thione, Dihydropyridin-2-one, 1,2,4-triazoline-3-thione, dihydropyridine-4-thione, dihydropyridin-2-one, isoindole, indole, indazole, benzimidazole, benzimidazole-2-thione, benzimidazol-2-one, benzoxazoline-2-thione, azaindenes, benzoxazoline-2-one, benzoxazoline-2-thione, benzothiazolin-2-one, carbamol, purine, carboline, phenoxazine, phenothiazine and condensed rings at various condensation positions, such as pyrazolepyridines, pyrazolopyrimidines, pyrazolopyrroles, pyrazoboxazoles, pyrazolothiazoles, pyrazolotriazoles; Imidazolopyridines, imidazolopyrimidines, midazolopyrroles, imidazolomidazoles, imidazoboxazoles, imidazobthiazoles and imidazolotriazoles.

Particularly preferred examples of heterocyclic aromatic rings include pyrrole, imidazole, pyrazole, triazole, tetrazole, thiazoline-2-thione, oxazoline-2-thione, indole, indazole, benzimidazole, 1,3,4-thiadiazoline-2-thione, azaindene, tetrazoline-5-thione, 1,3,4-oxadiazoline-2-thione, 1,2,4-triazoline-3-thione and condensed rings at various condensation positions such as pyrazolopyridines and pyrazolomidazoles. The particularly preferred examples of the heterocyclic aromatic rings include a ring containing a pyrazole nucleus such as pyrazole, indazole and pyrazolopyridine.

These heterocyclic groups may bear a substituent. Suitable substituents include a mercapto group, a nitro group, a carboxyl group, a sulfo group, a phosphono group, a hydroxyl group, an alkyl group, an aralkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxyl group, a sulfonylamino group, an amino group, an acylanino group, a sulfonylamino group, a ureido group, a urethane group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a sulfonyl group, a sulfinyl group, a halogen atom, a oyano group, an aryloxycarbonyl group, an acyl group, an alkoxycarbonyl group, an acyloxy group, a carbonamido group, a sulfonamido group and a phosphonamido group. The heterocyclic group is preferably substituted by one or more nitro groups.

Specific examples of the compound represented by formula (I) are shown below for illustrative purposes, but are not intended to limit the scope of the invention.

* comparative compounds

The compounds of formula (I) according to the invention can be synthesized by reacting a compound of formula (IV) and a corresponding hydrazine compound of formula (V) in an aprotic solvent (e.g. tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, acetonitrile) according to the reaction scheme shown below: where Z and R are as defined above.

The compound of formula (IV) can be prepared by reacting a compound of formula

with trichloromethylchloroformate in the presence of a base. Alternatively, a compound of the formula

or

(wherein Z is as defined above) can be used instead of the compound of formula (IV).

The hydrazine compounds of formula (V) are commercially available or can generally be prepared by acid hydrolysis of a corresponding known formylhydrazine compound The compounds of formula (V) can be efficiently prepared by forming a protected hydrazine using a carbobenzoxy group (CBZ group) or a t-butoxycarbonyl group (Boc group) as a protecting group for hydrazine and removing the protecting group according to a conventional method well known in the field of peptide chemistry.

Typical synthesis examples for compounds of formula (I) are described below.

SYNTHESIS EXAMPLE 1 Synthesis of compound 4

To a mixture of 32.6 g of 5-nitromdazole and 500 ml of tetrahydrofuran, 6.0 ml of trichloromethyl chloroformate was added dropwise over 30 minutes under cooling with ice. Then, 26 ml of triethylamine was added dropwise over 30 minutes. The mixture was warmed to room temperature and stirred at that temperature for 2 hours. After cooling with ice, 15.9 g of p-tolylhydrazine hydrochloride was added to the mixture, and then 14 ml of triethylamine was slowly added. The temperature of the mixture was returned to room temperature and the mixture was stirred for a whole day. All insolubles were separated by filtration and the volatile component was removed by distillation under reduced pressure. The residue was purified by silica gel column chromatography to obtain 18.7 g of compound 4. The chemical structure of the product was confirmed by NMR spectrum, IR spectrum and elemental analysis.

SYNTHESIS EXAMPLE 2 Synthesis of compound 17

4 ml of concentrated hydrochloric acid were added to a mixture of 11.7 g of a compound of the formula:

and 100 ml of methanol were added, followed by stirring at room temperature for 3 hours. The volatile component was removed by distillation under reduced pressure. The resulting product was reacted with carbonyl-di-(6-nitroindazole) which was synthesized in the same manner as in Synthesis Example 1 in tetrahydrofuran in the presence of triethylamine, and the reaction mixture was purified by column chromatography to obtain 6.2 g of Compound 17. The chemical structure of the product was confirmed by NMR spectrum, IR spectrum and elemental analysis.

SYNTHESIS EXAMPLE 3 Synthesis of compound 8

4 ml of concentrated hydrochloric acid were added to a mixture of 10 g of a compound of the formula:

and 80 ml of ethanol were added, after which the mixture was stirred at room temperature for 24 hours. The volatile component was distilled off under reduced pressure. Then 100 ml of dimethylformamide, 7.9 g of a compound of the formula (prepared by reacting p-nitrophenyl (chlorocarbonate with 6-nitrolendazole in the presence of DBU) and 3.4 ml of triethylamine were added to the residue, and the resulting mixture was stirred for 24 hours in a nitrogen atmosphere. The reaction mixture was poured into 1 N hydrochloric acid, and the resulting mixture was extracted with ethyl acetate. The extract was dried, concentrated and purified by silica gel column chromatography to obtain 8.4 g of the desired compound. The chemical structure of the product was confirmed by NMR spectrum, IR adsorption spectrum and elemental analysis.

The compound of formula (I) is incorporated into a photographic emulsion layer or a hydrophilic colloidal layer by dissolving the compound in water or a water-miscible organic solvent (if desired, an alkali hydroxide or a tertiary anhydride may be added to form a salt) and adding the solution to a hydrophilic colloid solution (e.g., a silver halide emulsion and an aqueous gelatin solution). If desired, the pH of the resulting mixture may be adjusted by adding an acid or an alkali.

The compounds of formula (I) may be used either individually or in a combination of two or more thereof. The amount to be added is suitably selected depending on the properties of a silver halide emulsion with which it is to be combined, preferably in Range from 1 x 10⁻⁵ to 5 x 10⁻² moles, in particular from 2 x 10⁻⁵ to 1 x 10⁻² moles, per mole of silver halide.

It is preferred that the compound of formula (I) is used in combination with a hydrazine compound represented by formula (III):

wherein R₃₁ represents an aliphatic group or an aromatic group; R₃₂ represents a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an amino group, a carbamoyl group or an oxycarbonyl group; G₁ represents a carbonyl group, a sulfonyl group, a

sulfoxy group, a

group or an iminomethylene group; A₁ and A₂ each represent a hydrogen atom, or one of A₁ and A₂ represents a hydrogen atom and the other represents a substituted or unsubstituted alkylsulfonyl group, a substituted or unsubstituted arylsulfonyl group, or a substituted or unsubstituted acyl group.

In formula (III), the aliphatic group represented by R₃₁ preferably includes those having 1 to 30 carbon atoms, particularly a straight-chain, branched or cyclic alkyl group having 1 to 20 carbon atoms. The branched alkyl group may be cyclized to form a saturated heterocyclic ring containing at least one heteroatom. The alkyl group may further be substituted with an aryl group, an alkoxy group, a sulfoxy group, a sulfonamido group and a carbonamido group.

The aromatic group represented by R₃₁ is a monocyclic or bicyclic group or an unsaturated heterocyclic group. The unsaturated heterocyclic group may be condensed with a monocyclic or bicyclic aryl group to form a heteroaryl group. Examples of the aromatic group include a benzene ring, a naphthalene ring, a pyridine ring, a pyrimidine ring, an imidazole ring, a pyrazole ring, a quinoline ring, an isoquinoline ring, a benzimidazole ring, a thiazole ring and a benzothiazole ring, with those having a benzene ring being particularly preferred.

R₃₁ preferably represents an aryl group.

The aryl group or unsaturated heterocyclic group represented by R₃₁ may have a substituent which typically includes an alkyl group, an aralkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryl group, a substituted amino group, an acylamino group, a sulfonylamino group, a ureido group, a urethane group, an aryloxy group, a sulfamoyl group, a sulfonyl group, a sulfinyl group, a hydroxyl group, a halogen atom, a cyano group, a sulfo group, an alkyloxycarbonyl group, an aryloxycarbonyl group, an acyl group, an alkoxycarbonyl group, an acyloxy group, a carbonamido group, a sulfonamido group, a carboxyl group, a phosphoric acid amide group, a diacylamino group and an imido group. Among these substituents are a straight-chain, branched or cyclic alkyl group (in particular having 1 to 20 carbon atoms), an aralkyl group (in particular a monocyclic or bicyclic group having 1 to 3 carbon atoms in the alkyl group half), an alkoxyl group (in particular having 1 to 20 carbon atoms, a substituted amino group (in particular an amino group which is substituted with an alkyl group having 1 to 20 carbon atoms), an acylamino group (in particular having 2 to 30 carbon atoms), a sulfonamido group (in particular having 1 to 30 carbon atoms), a ureido group (in particular having 1 to 30 carbon atoms) and a phosphoric acid amide group (in particular having 1 to 30 carbon atoms) are preferred.

The alkyl group represented by R₃₂ in formula (III) preferably contains 1 to 4 carbon atoms and may have a substituent, for example, a halogen atom, a cyano group, a carboxyl group, a sulfo group, an alkoxyl group, a phenyl group or a sulfonyl group.

The aryl group represented by R₃₂ preferably includes a monocyclic or bicyclic aryl group such as one containing a benzene ring. The aryl group may have a substituent such as a halogen atom, an alkyl group, a cyano group, a carboxyl group, a sulfo group or a sulfonyl group.

The alkoxy group represented by R₃₂ preferably contains 1 to 8 carbon atoms and may be substituted with a halogen atom or an aryl group.

The aryloxy group represented by R₃₂ is preferably monocyclic and may be substituted with a halogen atom.

The amino group represented by R₃₂ may be substituted with an alkyl group, a halogen atom, a cyano group, a nitro group, a carboxyl group, etc. Among the amino groups, an unsubstituted amino group, a Alkylamino group having 1 to 10 carbon atoms and an arylamino group are preferred.

The carbamoyl group represented by R₃₂ may be substituted with an alkyl group, a halogen atom₁, a cyano group or a carboxyl group. Among the carbamoyl groups, an unsubstituted carbamoyl group, an alkylcarbamoyl group having 1 to 10 carbon atoms and an arylcarbamoyl group are preferred.

The oxycarbonyl group represented by R₃₂ includes preferably an alkoxycarbonyl group having 1 to 10 carbon atoms and an aryloxy group. The hydroxycarbonyl group may be substituted with an alkyl group, a halogen atom, a cyano group, a nitro group, etc.

If G1 represents a carbonyl group, R32 preferably represents a hydrogen atom, an alkyl group (e.g. methyl, trifluoromethyl, 3-hydroxypropyl, 3-methanesulfonamidopropyl and phenylsulfonylmethyl), an aralkyl group (e.g. o-hydroxybenzyl) or an aryl group (e.g. phenyl, 3,5-dichlorophenyl, o-methanesulfonamidophenyl and 4-methanesulfonylphenyl) and preferably a hydrogen atom.

If G₁ represents a sulfonyl group, R₃₂ is preferably an alkyl group (e.g. methyl), an aralkyl group (e.g. o-hydroxyphenylmethyl), an aryl group (e.g. phenyl) or a substituted amino group (e.g. dimethylamino).

If G₁ represents a sulfoxy group, R₃₂ preferably represents a cyanobenzyl group or a methylthiobenzyl group.

If G₁

R₃₂ is preferably a methoxy group, an ethoxy group, a butoxy group, a phenoxy group or a phenyl group, and in particular a phenoxy group.

If G1 is an N-substituted or unsubstituted iminomethylene group, R32 preferably represents a methyl group, an ethyl group or a substituted or unsubstituted phenyl group.

The groups mentioned above as substituents for R₃₁ are also suitable substituents for the R₃₂ groups.

G₁ preferably represents a carbonyl group.

R₃₂ may be a group which causes the G₁-R₃₂ moiety to cleave from the residue according to formula (III) to induce cyclization to form a cyclic structure containing the -G₁- R₃₂ moiety. More specifically, this separation is effected by a cleaving agent represented by formula (a):

-R₃₃ - Z�3;₁ (a)

wherein Z₃₁ represents a group which nucleophilically attacks G₁ to cleave the G₁-R₃₁-Z₃₁ moiety from the residue according to formula (a); R₃₁ represents a group obtained by removing a hydrogen atom from R₃₂; and R₃₁ and Z₃₁ together with G₁ form a cyclic structure after the nucleophilic attack of Z₃₁ on G₁.

More specifically, if the hydrazine compound of formula (III) undergoes a reaction such as oxidation to produce an intermediate represented by formula R₃₁-N=NG₁-R₃₃-Z₃₁, Z31 readily reacts nucleophilically with G₁ to separate R₃₁-N=N from G₁. The Z₃₁ group includes a functional group capable of reacting directly with G₁, e.g., OH, SH, NHR₃₄ (wherein R₃₄ represents a hydrogen atom, an alkyl group, an aryl group, -COR₃₅ or -SO₂R₃₅, where R₃₅ represents a hydrogen atom, an alkyl group, an aryl group, a heterocyclic ring, etc.), -COOH (these functional groups may be temporally protected to release the functional group after hydrolysis by an alkali, etc.), or a functional group capable of reacting with G₁ upon reaction with a nucleophilic

Agent, e.g. a hydroxide ion and a sulphite ion), such as

and

wherein R₃₆ and R₃₇ each represents a hydrogen atom, an alkyl group, an alkylene group, an aryl group or a heterocyclic group).

The ring formed by G1, R33 and Z31 is preferably a 5- or 6-membered ring.

Among the groups represented by formula (a), preferred are those represented by either formula (b) or (c):

wherein Z₃₁ is as defined above; Rb¹, Rb², Rb³ and Rb⁴, which may be the same or different, each represents a hydrogen atom, an alkyl group (preferably having 1 to 12 carbon atoms), an alkenyl group (preferably having 2 to 12 carbon atoms) and an aryl group (preferably having 6 to 12 carbon atoms). B represents an atomic group necessary to form a substituted or unsubstituted 5- or 6-membered ring; m and n each represent 0 or 1; and (n+m) is 1 or 2.

In formula (b), the 5- or 6-membered ring formed by B includes a cyclohexene, cycloheptene, benzene, naphthalene, pyridine or quinoline ring.

Formula (c) is shown below:

wherein Z₃₁ is as defined above; Rc¹ and Rc², which may be the same or different, each represent a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a halogen atom, etc.; Rc³ represents a hydrogen atom, an alkyl group, an alkenyl group or an aryl group; p represents or 1; q represents an integer of 1 to 4; Rc¹, Rc² and Rc³ may together form a ring, provided that Z₃₁ is capable of intramolecular nucleophilic attack on G₁.

Rc¹ and Rc² each preferably represents a hydrogen atom, a halogen atom or an alkyl group, and Rc³ preferably represents an alkyl group or an aryl group.

q preferably represents an integer from 1 to 3. If q is 1, p represents 1; if q is 2, p represents 0 or 1; if q is 3, p represents 0 or 1; and if q is 2 or 3, the CRc¹Rc² moieties may be the same or different.

In formula (III), A₁ and A₂ are each a hydrogen atom, an alkylsulfonyl or arylsulfonyl group having not more than 20 carbon atoms (preferably a phenylsulfonyl group or a phenylsulfonyl group which is substituted such that the sum of the Hammett constants for the substituent group ( -values) is -0.5 or more), an acyl group having not more than 20 carbon atoms (preferably a benzoyl group which is substituted such that the sum of the Hammett constants for the substituent group ( -values) is -0.5 or more), or a straight-chain, branched or cyclic substituted or unsubstituted aliphatic acyl group (the substituent includes a halogen atom, an ether group, a sulfonamido group, a carboxyl group and a sulfo group)).

A₁ and A₂ each preferably represents a hydrogen atom.

R₃₁ or R₃₂ in formula (III) may contain a ballast group which is generally used for immobile photographic additives such as couplers. A ballast group is a group which contains at least 8 carbon atoms and is relatively inert to the photographic properties. Suitable ballast groups are selected from an alkyl group, an alkoxyl group, a phenyl group, an alkylphenyl group, a phenoxy group and an alkylphenoxy group.

R₃₁ or R₃₂ may further contain a group which accelerates adsorption onto the silver halide grain. Examples of such an adsorption accelerating group are disclosed in US-A-4 385 108 and 4 459 347, JP-A-59-195233, JP-A-59-200231, JP-A-59-201045, JP-A-59-201046, JP-A-59-201047, JP-A-59-201048, JP-A-59-201049, JP-A-61-170733, JP-A-61-270744, JP-A-62-948 and Japanese Patent Application Nos. 62-67508, 62-67501 and 62-67510, including a thiourea group, a heterocyclic thioamido group, a heterocyclic mercapto group, and a triazole group.

Specific examples of the hydrazine compound represented by formula (III) are shown below, but the invention is not limited to these examples.

The compound of formula (I) and the hydrazine compound of formula (III) may be incorporated into the same layer or different layers.

In the invention, the hydrazine compound represented by formula (III) is preferably incorporated in the silver halide emulsion layer(s), but may also be incorporated in other non-light-sensitive hydrophilic colloid layers (e.g., a protective layer, an intermediate layer, a filter layer, and an antihalation layer). If the hydrazine compound is water-soluble, an aqueous solution of the hydrazine compound, or, if the hydrazine compound is sparingly soluble in water, a solution of the hydrazine compound in a water-miscible organic solvent such as alcohols, esters, and ketones, may be added to the hydrophilic colloid layers. When the hydrazine compound solution is added to a silver halide emulsion layer, it may be added at any time between the initial stage of chemical ripening and coating of the emulsion, but it is preferably added to the emulsion after completion of chemical ripening and before coating. In particular, it is most preferred to add the compound to a coating composition prepared prior to coating.

It is desirable that the optimum amount of the compound represented by formula (III) used is selected depending on the grain size of the silver halide emulsion, the halogen composition of the process and the degree of chemical sensitization, the relationship between the layer in which the compound is incorporated and the silver halide emulsion layers and the type of antifoggant used. The method for selecting the optimum amount of the compound is well known in the art. In general, the compound of formula (III) may preferably be used in an amount ranging from 1 x 10⁻⁶ to 1 x 10⁻⁴ mol, preferably 1 x 10⁻⁵ to 4 x 10⁻² mol, per mol of silver halide.

In addition to the hydrazine compound of the formula (III) described above, the compound of the formula (I) used in the invention can also be combined with other known hydrazine compounds. Examples of useful hydrazine compounds are described in Research Disclosure, Item 23516, p. 346 (Nov. 1983) and references cited therein, in US-A-4 080 207, 4 269 929, 4 276 364, 4 278 748, 4 385 108, 4 459 347, 4 560 638 and 4 478 928, British Patent 2 011 3918, JP-A-60-179734, JP-A-62-270948, JP-A-63-29751, JP-A-61-170733, JP-A-61-270744, JP-A-62-948, EP 217 310, JP-A-63-43538, JP-A-63- 104047, JP-A-63-121838, JP-A-63-129337, JP-A-63-223744 and JP- A-64-10233, US-A-4 686 167, JP-A-62-178246, JP-A-63-234244, JP- A-63-234245, JP-A-63-234246, JP-A-63-294552, JP-A-63-306438, JP-A-64-90439, JP-A-01-276127, JP-A-01-283548, JP-A-01-280747, JP-A-01-283549, JP-A-01-285940 and Japanese Patent Application Nos. 63-147339, 63-179760, 63-229163, 1-18377, 1-18378, 1-18379, 1-15755, 1-16814, 1-40792, 1-42615 and 1-42626.

The compound of formula (I) provides a negative image with high contrast if the hydrazine compound of formula (III) and a negative working emulsion are combined. On the other hand, the compound of formula (I) according to the invention can be used in combination with an internal latent image type silver halide emulsion. It is preferable to take advantage of combining the compound of formula (I) with the hydrazine compound of formula (III) and a negative working emulsion to obtain a negative image with high contrast.

If the photographic material according to the invention is used for forming a negative image with high contrast, fine silver halide grains having an average grain size of 0.7 µm or less, and particularly 0.5 µm or less are preferably used. The grain size distribution is not substantially limited, but monodispersion is preferred. The terminology monodispersion means a dispersion in which at least 95% by weight or number of the grains fall within a size range of ± 40% of an average grain size.

The silver halide grains for providing a photographic emulsion usable in the practical use of the invention may have a regular crystal form such as an octahedral form, a rhombic dodecahedral form and a tetradecahedral form; or may have an irregular crystal form such as a spherical form and a plate-like form, or may have a composite formed of these crystal forms.

Individual silver halide grains may have a uniform phase or different phases between the interior and the surface layer.

During silver halide grain formation or physical ripening of the grains, a cadmium salt, a sulfite salt, a lead salt, a thallium salt, a rhodium salt or a complex thereof, an iridium salt or a complex thereof may be present in the system.

The silver halide emulsion used in the invention may be any of silver chloride, silver bromide, silver iodobromide and silver iodochlorobromide emulsion.

The silver halide emulsion usable in the invention may or may not be chemically sensitized. The chemical sensitization of the silver halide emulsions may be carried out by any known technique such as sulfur sensitization, reduction sensitization and noble metal sensitization, either alone or in combination thereof.

Among the precious metal sensitization techniques, gold sensitization is typical, which uses a gold compound, usually a gold complex. Complexes of precious metals other than gold, such as platinum, palladium and rhodium, can also be used. Specific examples of these precious metal compounds are described in US-A-2 448 060 and GB-B-618 016.

Sulfur sensitization is carried out using a sulfur compound contained in gelatin, as well as using various sulfur compounds, e.g. thiosulfates, thioureas, thiazoles and rhodanines.

In the preparation for the silver halide emulsion described above, it is preferable to add an iridium salt or a rhodium salt before completion of physical ripening, particularly during grain formation.

In order to obtain an increased maximum density (Dmax), a silver halide emulsion layer of the light-sensitive material according to the invention preferably contains two monodisperse emulsions having different average grain sizes, as taught in JP-A-61-223734 and JP-A-62-90646. In this case, the monodisperse grains of the smaller size are preferably chemically sensitized, particularly sulfur sensitized. The monodisperse grains of the larger size may or may not be chemically not be sensitized. In general, since the latter grains (larger grains) tend to form black pepper upon chemical sensitization, chemical sensitization is not carried out on the larger grains. In such cases where chemical sensitization of the larger grains is carried out, it is preferable to carry out light chemical sensitization so that no formation of black pepper is caused. Light chemical sensitization can be achieved by reducing the time or temperature for chemical sensitization or the amount of chemical sensitizer added, as compared with the chemical sensitization of the smaller grains. The difference in sensitivity to the monodisperse emulsion of larger size and the monodisperse emulsion of smaller size is not particularly limited, but the difference is expressed as ΔLogE and is generally 0.1 to 1.0, preferably 0.2 to 0.7. The larger size monodisperse emulsion preferably has a higher log. The terminology "sensitivity" referred to herein means a sensitivity of a sample prepared by coating each emulsion containing the hydrazine compound on a support and processing the coated material with a developer having a pH of 10.5 to 12.3 containing at least 0.15 mol/l of sulfite ion. The grain size of the smaller size monodisperse grains is not more than 90%, preferably not more than 80%, of the average grain size of the larger size monodisperse grains. The average grain size of the silver halide emulsion grains is preferably 0.02 to 1.0 µm, particularly 0.1 to 0.5 µm, and the average grain size of each of the larger size grains and the smaller size grains is preferably within this range.

If two or more emulsions with different grain sizes are used, the monodisperse emulsion with smaller size is preferably coated with a silver coverage weight of 40 to 90 wt.%, especially 50 to 80 wt.%, based on the total silver coverage.

The monodisperse emulsions having different grain sizes may be incorporated into the same layer or into separate layers. In the latter case, it is preferable to incorporate the emulsion with larger size into an upper layer and the emulsion with smaller size into a lower layer.

The total silver application is preferably 1 to 8 g/m².

For the purpose of increasing the sensitivity, the light-sensitive material according to the invention may contain sensitizing dyes such as cyanine dyes and merocyanine dyes as described in JP-A-55-52050, pp. 45-53. The sensitizing dyes may be used either individually or in combination of two or more of them. A combination of sensitizing dyes is often used for supersensitization. The emulsion may also contain, in addition to the sensitizing dye, a dye which does not have a spectral sensitization activity per se but exhibits a supersensitization activity, or may contain a substance which does not substantially absorb visible light but exhibits a supersensitization activity. Examples of useful sensitizing dyes and dyes which exhibit supersensitization and substances which exhibit supersensitization are described in Research Disclosure, Vol. 176, No. 17643, p. 23, IV-J (Dec. 1978).

In order to prevent fogging during the preparation, storage or photographic processing of the light-sensitive material or to stabilize the photographic properties, various compounds can be incorporated into the light-sensitive material of the present invention. Such compounds include: azoles such as benzothiazole salts, nitroindazoles, chlorobenzimidazoles, bromobenzimidazoles, mercaptothiazoles, mercaptobenzothiazoles, mercaptothiadiazoles, aminotriazoles, benzothiazoles and nitrobenzotriazoles; mercaptopyrimidines; mercaptotriazines; thioketo compounds such as oxazolinethione; azaindenes such as triazaindenes, tetraazaindenes (particularly 4-hydroxy-substituted (1,3,3a,7)-tetraazaindenes) and pentaazaindenes; Benzenethiosulfonic acids, benzenesulfinic acids, benzenesulfonic acid amides and many other compounds known as antifogging agents or stabilizers. Among these, benzotriazoles (e.g. 5-methylbenzotriazole) and nitromethylazole (e.g. 5-nitromedazole) are preferred. If desired, these compounds can be incorporated into the processing solutions.

Examples of a development accelerator or an infectious nucleation development accelerator which can be suitably used in the invention include the compounds disclosed in JP-A-53-77616, JP-A-54-37732, JP-A-53-137133, JP-A-60-140340 and JP-A-60-14959, as well as various compounds containing a nitrogen or sulfur atom.

These accelerators are usually used in an amount of 1.0 x 10⁻¹ to 0.5 g/m², preferably 5.0 x 10⁻³ to 0.1 g/m², although the optimum amount varies depending on the type of the accelerator.

The photographic emulsion layers or other hydrophilic colloidal layers may contain a desensitizer.

An organic desensitizer which can be used in the invention is specified by its polarographic half-wave potential, i.e. an oxidation-reduction potential determined by polarography. That is, it is specified by a positive sum of the polarographic anode potential and a cathode potential. The determination of the oxidation-reduction potential by means of polarography is described, for example, in US-A-3,501,307. Organic desensitizers which contain at least one water-soluble group, for example a sulfo group and a carboxyl group, are preferred. The water-soluble group can be in the form of a salt with an organic base, e.g. ammonia, pyridine, triethylamine, piperidine and morpholine, or an alkali metal, e.g. sodium and potassium.

Preferred organic desensitizers are those described in JP-A-63-133145, pp. 55-72 (particularly the compounds represented by formulae (III) to (V)).

The organic desensitizer is added to the silver halide emulsions usually in an amount of 1.0 x 10⁻⁸ to 1.0 x 10⁻⁴ mol/m², preferably 1.0 x 10⁻⁴ to 1.0 x 10⁻⁴ mol/m².

The emulsion layers or other hydrophilic colloidal layers may contain a water-soluble dye as a filter dye or for the purpose of preventing irradiation or for other purposes. Useful filter dyes are dyes for reducing the photographic sensitivity, preferably ultraviolet absorbers with a spectral absorption maximum in the intrinsic sensitivity range of silver halide, and dyes which show extensive light absorption mainly in the range of 380 to 600 nn, which are used to improve safety against safety addiction when processing light-sensitive materials in a bright room.

These dyes are preferably fixed with a mordant to an emulsion layer or a hydrophilic colloidal light-insensitive layer which is further away from the support than the silver halide emulsion layer, depending on the purpose.

The ultraviolet absorbent is usually used in an amount of 1 x 10⁻² to 1 g/m², preferably 50 to 500 mg/m, although the amount varies somewhat depending on the molar extinction coefficient of the absorbent.

The ultraviolet absorber can be incorporated into a coating composition in the form of a solution in a suitable solvent, e.g., water, an alcohol (e.g., methanol, ethanol, and propanol), acetone, methyl cellosolve, or a mixture thereof. Suitable ultraviolet absorbers that can be used include aryl-substituted benzotriazole compounds, 4-thiazolidone compounds, benzophenone compounds, stannic acid ester compounds, butadiene compounds, benzoxazole compounds, and ultraviolet light absorbing polymers. Specific examples of these ultraviolet absorbents are described in US-A-3,533,794, 3,314,794 and 3,352,681, JP-A-46-2784, US-A-3,705,805, 3,707,375, 4,045,229, 3,700,455 and 3,499,762 and DE-C-1,547,863.

Filter dyes that can be used include oxazole dyes, hemioxanol dyes, styryl dyes, Merocyanine dyes, cyanine dyes and azo dyes. To minimize the color remaining after development processing, water-soluble dyes or dyes that are decolorized with alkali or sulfite ions are preferred.

Specific examples of suitable filter dyes include the pyrazolone oxonol dyes described in US-A-2,274,782, the diarylazo dyes described in US-A-2,956,879, the styryl dyes and butadienyl dyes described in US-A-3,423,207 and 3,384,487, the merocyanine dyes described in US-A-2,527,583, the merocyanine dyes and oxonol dyes described in US-A-3,486,897, 3,652,284 and 3,718,472, the enaminohemioxonol dyes described in US-A-3,976,661 and the GB-B-584,609 and 1,177,429. JP-A-48- 85130, JP-A-49-99620, JP-A-49-114420 and US-A-2 533 472, 3 148 187, 3 177 078, 3 247 127, 3 540 887, 3 575 704 and 3 653 905.

The dyes are added to a coating composition for a light-insensitive hydrophilic colloidal layer in the form of a solution in a suitable solvent, e.g. water, an alcohol (e.g. methanol, ethanol and propanol), acetone, methyl cellosolve or a mixture thereof.

A suitable amount of the dye to be added is generally 1 x 10⁻³ to 1 g/m², particularly 1 x 10⁻³ to 0.5 g/m².

The photographic emulsion layers or other hydrophilic colloidal layers may contain an organic or inorganic hardening agent such as chromates, aldehydes (eg formaldehyde and glutaraldehyde), N-methylol compounds (eg dimethylol urea), active vinyl compounds (eg 1,3,5-triacryloyl-hexahydro-s-triazine and 1,3-vinylsulfonyl-2-propanol), active halogen compounds (e.g. 2,4-dichloro-6-hydroxy-s-triazine) and mucohalogenic acids, either individually or in combination thereof.

The photographic emulsion layers or other hydrophilic colloidal layers may further contain various surfactants for the purpose of a coating aid, antistatic, anti-slip, emulsification and dispersion aid, anti-blocking and anti-seizure, and improving the photographic characteristics (e.g., acceleration of development, increase in contrast and increase in sensitivity). Surfactants particularly useful in the invention are polyalkylene oxides having a molecular weight of 600 or more as described in JP-B-58-9412 (the term "JP-B" as used herein means an "examined published Japanese patent application"). For particular use as an antistatic agent, fluorine-containing surfactants are preferred. For details of fluorine-containing surfactants, reference is made to US-A-4,201,586, JP-A-60-80849 and JP-A-59-74554.

For the purpose of preventing blocking, the photographic emulsion layers or other hydrophilic colloidal layers may further contain a matting agent such as silica, magnesium oxide and polymethyl methacrylate.

For the purpose of improving dimensional stability and the like, the photographic emulsions may contain a dispersion of a water-insoluble or sparingly water-soluble synthetic polymer. Examples of such a polymer include homopolymers or copolymers of alkyl (meth)acrylate, alkoxyalkyl (meth)acrylate and glycidyl (meth)acrylate and copolymers which include these monomers and acrylic acid, methacrylic acid, etc.

The silver halide emulsion layers and other layers preferably contain a compound having an acid radical. Examples of suitable compounds having an acid radical are organic acids, e.g. salicylic acid, acetic acid and ascorbic acid; and homopolymers or copolymers comprising an acid monomer, e.g. acrylic acid, maleic acid and phthalic acid. Regarding these compounds, reference is made to JP-A-61-223834, JP-A-61-228437, JP-A-62-25745 and JP-A-62-55642. Among them, ascorbic acid as a low molecular weight compound and an aqueous latex of a copolymer comprising an acid monomer (e.g. acrylic acid) and a cross-linked monomer having at least two unsaturated groups (e.g. divinylbenzene) as a high molecular weight compound are preferred.

The silver halide light-sensitive material of the present invention can be processed with a stable developing solution to obtain ultra-high contrast and high sensitivity. There is no need to use a conventional infectious developer or a highly alkaline developer having a pH of nearly 13 as described in US-A-2,419,975.

A negative image having a sufficiently high contrast can be obtained by processing the silver halide light-sensitive material of the present invention with a developer containing 0.15 mol/l or more of sulfite ions as a preservative and having a pH between 10.5 and 12.3, in particular between 11.0 and 12.0.

The developing agent that can be used in the developer is not particularly limited. In view of the ease of To obtain a satisfactory dot quality, the developer preferably contains dihydroxybenzenes. A combination of dihydroxybenzene and 1-phenyl-3-pyrazolidone or a combination of dihydroxybenzene and p-aminophenol is sometimes used. The developing agent is preferably used in an amount of 0.05 to 0.8 mol/l. When a combination of dihydroxybenzene and 1-phenyl-3-pyrazolidone or p-aminophenol is used, the former is preferably used in an amount of 0.05 to 0.5 mol/l, and the latter is preferably used in an amount of not more than 0.06 mol/l.

Sulfites which can be used in the developer as a preservative include sodium sulfite, potassium sulfite, lithium sulfite, sodium bisulfite, potassium metabisulfite and formaldehyde sodium bisulfite. The sulfite is preferably used at a concentration of 0.4 mol/l or higher, particularly 0.5 mol/l or higher.

The developer may contain the compound disclosed in JP-A-56-24347 as a silver stain inhibitor, the compound disclosed in JP-A-61-267759 as a dissolving aid, and the compound disclosed in JP-A-60-93433 or JP-A-62-186259 as a pH buffer.

As stated above, the compound represented by formula (I) can be used in combination with an internal latent image type silver halide emulsion as well as with a negative working emulsion. When combined with an internal latent image type silver halide emulsion, the compound of formula (I) is preferably incorporated into an internal latent image type silver halide emulsion layer. They can also be incorporated into a hydrophilic colloidal layer adjacent to the internal latent image type silver halide emulsion layer. Hydrophilic colloidal Layers into which the compound of formula (I) can be incorporated are not limited in their function, provided that the nucleating agent is not inhibited from diffusing to the silver halide grains.

Possible layers include color material layers, interlayers, filter layers, protective layers and antihalation layers.

The amount of the compound of formula (I) to be used varies depending on the characteristics of the silver halide emulsions used, the chemical structure of the nucleating agent and the conditions for development and is therefore subject to further variations. From a practical standpoint, a useful amount is about 0.005 mg to 500 mg, preferably about 0.01 to 100 mg, per mole of silver in an internal latent image type silver halide emulsion. When the compound is incorporated in a hydrophilic colloidal layer adjacent to the emulsion layer, it is used in the same amount as above per mole of silver contained in the same area of the internal latent image type emulsion layer. The terminology "internal latent image type silver halide emulsion" as used here is defined in JP-A-61-170733, p. 10, upper column, and in British Patent 2 089 057, pp. 18-20.

For preferred internal latent image type emulsions for use in the invention, reference may be made to European Patent No. 267,482, page 10, line 57, to page 11, line 26, and for preferred silver halide grains therefor, ibid., page 11, line 37, to page 11, line 56.

The internal latent image type emulsion can be spectrally sensitized to blue light or a relatively longer wavelength, green light, red light or infrared light, using sensitizing dyes. Sensitizing dyes to be used include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, styryl dyes, hemicyanine dyes, oxonol dyes and hemioxonol dyes. These sensitizing dyes include, for example, the cyanine dyes or merocyanine dyes described in JP-A-59-40638, JP-A-59-40636 and JP-A-59-38739.

The light-sensitive material of the present invention may contain color image-forming couplers (e.g. cyan, magenta and yellow couplers) as coloring material. It is also possible to develop the light-sensitive material with a developer containing the color image-forming couplers.

Specific examples of cyan, magenta and yellow couplers which can be used in the invention are described in Research Disclosure, 17643, Item VII-D (Dec. 1978), and ibid, 18717 (Nov. 1979).

In addition, couplers containing dyes having a moderate diffusibility, colorless couplers, DIR couplers capable of releasing a development inhibitor upon a coupling reaction, or couplers capable of releasing a development accelerator upon the coupling reaction can also be used.

Yellow couplers which can be used in the invention typically include oil-protected acylacetamide couplers.

It is advantageous to use 2-equivalent yellow couplers, which typically include oxygen-releasing yellow couplers and nitrogen-releasing yellow couplers. α-pivaloylacetanilide couplers are excellent in dye stability, particularly stability to light. On the other hand, α-benzoylacetanilide couplers provide high color densities.

Magenta couplers to be used in the invention include oil-protected type indazolone or oyanoacetyl couplers, preferably 5-pyrazolone couplers and pyrazoloazole couplers such as pyrazobriazoles. 5-pyrazolone couplers having an arylamino group or an acylamino group at the 3-position are preferred in view of the tone and density of the developed dyes.

Releasable groups from 2-equivalent 5-pyrazolone couplers preferably include nitrogen-releasing groups, which are described in US-A-4,310,619, and arylthio groups, which are described in US-A-4,351,897. 5-pyrazolone couplers with a ballast group, as described in EP 73,636, provide high color densities.

Pyrazoloazole couplers include pyrazolobenzimidazoles described in US-A-3,379,899 and preferably pyrazolo[5,1- c][1,2,4]triazoles described in US-A-3,725,067, pyrazolotetrazoles described in Research Disclosure, 24220 (June 1984), and pyrazolopyrazoles described in Research Disclosure, 24230 (June 1984). From the standpoint of reduced yellow side absorption and light stability of the dyes produced, imidazolo[1,2-b]pyrazoles described in EP 119 741 are preferred. The pyrazolo[1,5- b][1,2,4]triazole described in EP 119 860 is particularly preferred.

Cyan couplers usable in the invention include oil-protected naphthol and phenol couplers. Typical examples of cyan couplers are naphthol couplers described in US-A- 2,474,293, preferably 2-equivalent oxygen-releasing naphthol couplers described in US-A-4,052,212, 4,146,396, 4,228,233 and 4,296,200. Examples of phenol couplers are described in US-A-2,369,929, 2,801,171, 2,772,162 and 2,895,826. Cyan couplers which exhibit stability to moisture and heat are preferably used in the invention. Typical examples of such cyan couplers are phenyl couplers having an alkyl group of 2 or more carbon atoms at the m-position of the phenol nucleus as described in US-A-3,772,002, 2,5-diacylamino-substituted phenol couplers and phenol couplers having a phenylureido group at the 2-position and an acylamino group at the 5-position.

In order to correct undesirable absorption in the shorter wavelength range, such as in dyes formed from magenta and cyan couplers, it is preferred to use colored couplers in color light-sensitive materials for photographing.

The graininess can be improved by using couplers which produce dyes with a moderate scattering power. Examples of such couplers are described in US-A-4 366 237 and GB-B-2 125 570 (magenta couplers); EP 96 570 and DE-C-3 234 533 (yellow, magenta or cyan couplers).

Dye-forming couplers and the special couplers described above may be in the form of a polymer, including that of a diner. Typical examples of polymerized dye-forming couplers are described in US-A-3,451,820 and 4,080,211. Specific examples of polymerized Magenta couplers are described in GB-B-2 102 173 and US-A-4 367 282.

In order to satisfy the characteristics required for photosensitive materials, two or more of the above-described couplers may be incorporated into the same photosensitive layer, or the same coupler may be incorporated into two or more layers.

The standard amount of color couplers to be used is in the range of 0.001 to 1 mole per mole of light-sensitive silver halide. Specifically, 0.01 to 0.5 moles of a yellow coupler, 0.003 to 0.3 moles of a magenta coupler and 0.002 to 0.3 moles of a cyan coupler are used per mole of silver halide.

Developing agents such as hydroxybenzenes (e.g. hydroquinone, aminophenols and 3-pyrazolidones can be incorporated into the emulsions or light-sensitive materials.

The photographic emulsion which can be used in the invention can also be combined with a compound (coloring material) which releases a dye image in a color diffusion transfer process which releases a diffusible dye in accordance with the development of silver halide to provide a desired transferred image on an image-receiving layer. Various coloring materials for the color diffusion transfer process have been proposed. Among them, preferred are coloring materials which are non-diffusible but capable of releasing a diffusible dye upon splitting off during an oxidation-reduction reaction with an oxidation product of a developing agent (or an electron transfer agent, hereinafter referred to as DRR compounds), with those having an N-substituted sulfamoyl group being particularly preferred. are preferred. Among others, DRR compounds having an o-hydroxyarylsulfamoyl group as described in US-A-4,055,428, 4,053,312 and 4,336,322 and DRR compounds having a redox nucleus as described in JP-A-53-149328 are suitable for combination with a nucleating agent. The combined use of such DRR compounds remarkably reduces the temperature dependence of processing performance.

After imagewise exposure, processing of the light-sensitive material is preferably carried out by color development with a surface developer having a pH of 11.5 or lower containing a primary aromatic amine as a color developing agent, either after or during light fogging or chemical fogging using a nucleating agent, followed by bleaching and fixing to directly form a positive color image. The developer to be used preferably has a pH between 10.0 and 11.0.

Fogging can be effected either by a light fogging process in which the entire area of a photosensitive layer is subjected to a second exposure or by a chemical fogging process in which development processing is carried out in the presence of a nucleating agent. Development processing can be carried out in the presence of a nucleating agent and fogging light. Likewise, a photosensitive material containing a nucleating agent can be subjected to fogging exposure.

The light-veiling process is described in EP-B-267 482, p. 17, line 15, to p. 17, line 46. Useful nucleating agents are described in ibid, p. 17, line 27, to p. 21, line 31. In particular, the nucleating agents represented by the formulas (N-1) and (N-2) are preferred. Specific examples of these compounds are (NI-1) to (NI-10) as shown on page 19 and (N-II-1) to (N-II-12) as shown on page 21 of the above European Patent.

Nucleation accelerators which can be used in the invention are described in ibid, p. 21, line 48, to p. 22, line 17. In particular, (A-1) to (A-13) according to p. 21, line 48, to p. 22, line 17 are preferred.

Color developers which can be used for development processing of the light-sensitive material of the present invention are described in ibid, p. 22, line 18, to p. 22, line 29. Preferred examples of primary aromatic amine color developing agents are p-phenylenediamine compounds such as 3-methyl-4-amino-N-ethyl-N-(β-methanesulfonamidoethyl)aniline, 3-methyl-4-amino-N-ethyl-N-(β-hydroxyethyl)aniline, 3-methyl-4-amino-N-ethyl-N-methoxyethylaniline and their salts (e.g. sulfate and hydrochloride).

In order to form a direct positive color image by color diffusion transfer using the light-sensitive material according to the invention, black/white developers such as phenidone compounds can also be used.

Photographic emulsion layers are usually subjected to bleaching after color development. Bleaching can be carried out simultaneously with fixing (combined bleaching and fixing) or these two steps can be carried out separately. To speed up processing, bleaching can be followed by bleach-fixing or fixing can be followed by bleach-fixing.

A bleaching solution or a bleach-fixing solution usually contains an aminopolycarboxylic acid iron complex salt as a bleaching agent. Additives that can be used in the bleaching or bleach-fixing solution are described in JP-A-62-215272, pp. 20 to 30.

After desilvering (bleach-fixing or fixing), washing and/or stabilization are carried out. Preferably, water which has been softened is used as washing water or as stabilizing solution. Water softening treatments can be carried out by means of an ion exchange resin described in JP-A-62-288838 or by means of a method using a reverse osmosis device. The method described in JP-A-62-288838 supra is particularly preferred.

Additives which can be used in the washing and stabilizing steps include those described in JP-A-62-215272, pp. 30 to 36.

The replenishment rate at each processing step is preferably low. It is preferably 0.1 to 50 times, particularly 3 to 30 times the amount of the pre-bath transferred per unit area of a photosensitive material.

The compounds of the invention can be used for heat-developable, photosensitive materials which are described, for example, in US-A-4 463 079, 4 747 867, 4 478 927, 4 507 380, 4 500 626, 4 483 914, JP-A-58-149048, JP-A-58-149047, JP-A-59-152440, JP-A-59-154445, JP-A-59-165054, JP-A-59-180548, JP-A- 59-168439, JP-A-59-168439, JP-A-59-174832, JP-A-59-174833, JP-A-59-174834, JP-A-59-174835, JP-A-61-232451, JP-A-62-65038, JP-A-62-253159, JP-A-63-316848, JP-A-64-13546 and EP-210 660A2 and 220 746A2.

The heat-developable photosensitive material comprises a support having photosensitive silver halide disposed thereon, a binder, a compound for forming a dye and a reducing agent (the reducing agent may also serve as a material for forming a dye) and, if necessary, an organic silver salt and other additives may be incorporated therein.

The heat-developable light-sensitive material may be either a negative image forming material or a positive image forming material. For the positive image forming material, a direct positive emulsion including a system using a nucleating agent and a system using a fogging agent as a silver halide emulsion or a dye forming compound releasing a positive diffusible color image is used.

The transfer of a diffusible dye can be effected by various methods. For example, by transfer methods to a dye-fixing layer using an image-forming solvent, transfer to a dye-fixing layer using an organic solvent having a high boiling point, transfer to a dye-fixing layer using a hydrophilic hot solvent, and transfer to a dye-fixing layer containing a dye-receiving polymer using the property of heat diffusibility or sublimability of the diffusible dye have been proposed, and any of these methods can be used in the invention.

The solvent for forming an image described above includes, for example, water, which may be pure water as well as conventionally used water. The solvent may be a mixture of pure water and a low boiling point solvent such as methanol, dimethylformamide, acetone, diisobutyl ketone. Further, the solvent may be a solution containing an image formation accelerator, an antifogging agent, a development stopping agent and a hydrophilic hot solvent.

In the following, the invention is described in detail by means of examples, which, however, are not intended to limit the invention.

EXAMPLE 1 Preparation of the light-sensitive emulsion:

An aqueous silver nitrate solution and a mixed aqueous solution of potassium iodide and potassium bromide were simultaneously added to an aqueous gelatin solution kept at 50°C in the presence of 4 x 10-7 mol of iridium (III) chloride per mol of silver and ammonia while keeping a pag at 7.8 to prepare a cubic monodisperse emulsion having an average grain size of 0.28 µm and an average silver iodide content of 0.3 mol%. After the emulsion was desalted by a flocculation method, 40 g of inert gelatin per mol of silver was added. 5,5'-Dichloro-9-ethyl-3,3'bis(3-sulfopropyl)oxacarbocyanine as a sensitizing dye and a solution containing 10-3 mol of potassium iodide per mol of silver were added to the emulsion while keeping it at 50°C. After allowing the emulsion to stand for 15 minutes, the temperature was lowered.

Coating for the light-sensitive emulsion layer:

The emulsion prepared above was remelted and the hydrazine compounds shown below were added at 40ºC in the amounts shown.

Each of the compounds shown in Table 1 below was added to the emulsion. In addition, 5-methylbenzotriazole, 4-hydroxy-1,3,3a,7-tetraazaindene, compounds (i) and (ii) shown below, 30% by weight (based on gelatin) of polyethyl acrylate and compound (iii) shown below as a gelatin hardener were added. The resulting coating composition was coated on a 150 µm thick polyethylene terephthalate film having an undercoat layer comprising a vinylidene chloride copolymer at a silver coverage of 3.8 g/m² and dried to form an emulsion layer. Connection (i) Connection (ii): Compound (iii): 2.0 wt.% based on gelatin

Coating for the protective layer:

A composition comprising 1.5 g/m² of gelatin, 0.3 g/m² of polymethyl methacrylate particles (average particle size 2.5 µm) and the surfactants shown below were coated on the emulsion layer and dried to form a protective layer. Surfactants:

Assessment of performance:

Each of the resulting samples was illuminated with tungsten light of 3200 K through an optical wedge and a contact screen ("150L Cham Dot Typet", manufactured by Fuji Photo Film Co., Ltd.), developed with a developer of the following formulation at 34ºC for 30 seconds, fixed, washed and dried.

The dot quality and dot gradation of the processed samples were evaluated and the results obtained are shown in Table 1.

1) Dot gradation was determined by the equation:

Dot gradation = exposure amount that creates a dot area ratio of 95% ΔLogE (LogE95%) - exposure amount that creates a dot area ratio of 5% (LogE5%)

2) The point quality was assessed according to the following system by visual observation:

5 ... best quality

4 ... acceptable for practical use

3 ... lower limit for practical use

2 ... not acceptable for practical use

1 ... worst quality

Developer formulation:

Hydroquinone 50.0 g

N-methyl-p-aminophenol 0.3 g

Sodium hydroxide 18.0 g

5-Sulfosalicylic acid 55.0 g

Potassium sulphite 110.0 g

Disodium ethylenediaminetetraacetate 1.0 g

Potassium bromide 10.0 g

5-Methylbenzotriazole 0.4 g

2-Mercaptobenzimidazole-5-sulfonic acid 0.3 g

Sodium 3-(5-mercaptotetrazole) benzenesulfonate 012 g

N-n-Butyldiethanolamine 15.0 g

Sodium toluenesulfonate 8.0 g

Water to 1 liter

pH (adjusted with potassium hydroxide) pH 11.6

As can be seen from the results shown in Table 1, the samples containing the compound of formula (1) according to the invention show a considerably broadened dot gradation and an improved dot quality in comparison with samples containing the comparative compound. TABLE 1 Compound (a) (JP-A-61-214847): Compound (b) (JP-A-61-213847): Compound (c) (US Patent 4,684,604): Compound (d) (US Patent 4,684,604):

EXAMPLE 2

Each of the samples prepared in Example 1 was exposed in the same manner as in Example 1 and developed at 34°C for 30 seconds under the following conditions (A), (B) or (C) using an automatic plate-making developer ("Model FG 66°F", manufactured by Fuji Photo Film Co., Ltd.) filled with the same developer as in Example 1, and then fixed, washed and dried.

Development condition:

(A) Development processing was carried out immediately after the temperature of the developer in the automatic developer reached 34ºC (development with a fresh developer).

(B) Development processing was carried out after the developer charged in the automatic developer was allowed to stand for 4 days (development with an air-fatigued developer).

(C) Commercially available films ("GRADEX GA-100", manufactured by Fuji Photo Film Co., Ltd.; 50.8 cm x 61.0 cm) were exposed in such a manner that 50% of the area was developed and developed by the automatic developing machine filled with the developer at a processing rate of 200 films per day for consecutive 5 days. The development of the sample was carried out with the thus fatigued developer (development with a large volume of processing fatigued developer). The developer was added at a replenishment rate of 100 cc per film.

The photographic sensitivity of each processed sample was determined to evaluate the processing run stability, and the results obtained are shown in Table 2 below. From the standpoint of the run stability, it is desirable that the difference in sensitivity between the process conditions (A), (B) or (C) be minimized. As can be seen from the results in Table 2, the compound according to the invention unexpectedly improves the processing run stability. TABLE 2

Note: * ΔSB-A: Difference between the sensitivity (SA) when a fresh developer is used and the sensitivity (SB) when an air-fatigued developer is used.

**ΔSC-A: Difference between the sensitivity (SA) when a fresh developer is used and the sensitivity (SC) when a large volume of processing-fatigued developer is used.

EXAMPLE 3

An aqueous silver nitrate solution and an aqueous sodium chloride solution were simultaneously added to an aqueous gelatin solution kept at 50°C in the presence of 5 x 10-6 mol of (NH4)3RhCl6 per mol of Ag. After the soluble salts were removed in a conventional manner, gelatin was added to the emulsion. Since chemical ripening was not carried out, 2-methyl-4-hydroxy-1,3,3a,7-tetraazaindene was added as a stabilizer. The resulting emulsion was a cubic monodisperse emulsion with an average grain size of 0.15 µm.

To the emulsion was added 49 mg/m² of a hydrazine compound of the formula:

admitted.

To the emulsion was added each of the compounds shown in Table 3 below. A polyethyl acrylate latex was added in an amount of 30% by weight (solid basis) based on gelatin, and 1,3-vinylsulfonyl-2-propanol was added as a hardener. The resulting coating composition was coated on a polyester support at a silver coverage of 3.8 g/m². The gelatin coverage was 1.8 g/m².

A protective layer with the following composition was applied to the emulsion layer thus formed and dried.

Composition for the protective layer:

Gelatine 1.5 g/m²

Matting agent: Polymethyl methacrylate particles (average particle size: 2.5 µm) 0.3 g/m²

Surfactant as a coating aid:

Stabilizer: Thioctic acid 2.1 mg/m² Ultraviolet absorption dye:

Each of the resulting samples was imagewise exposed through an original as shown in the figure, developed at 38ºC for 20 seconds, fixed, washed and dried by means of a bright room printer ("P-607", manufactured by Dai Nippon Screen K.K.) The image quality on the white line image thus formed was evaluated as follows.

The photosensitive material for dot-to-dot work was exposed to light with an appropriate exposure amount so that a dot area of 50% of the original could form a dot area of 50% on the photosensitive material. As a result, if a 30 µm wide letter could be reproduced, the image quality was rated as 5 (best quality). On the other hand, if only a 150 µm wide letter could be reproduced under the same exposure condition, the image quality was rated as 1 (worst quality). The image quality between 5 and 1 was rated according to 2 to 4 by visual observation. A quality rated higher than 3 represented an acceptable level for practical use.

The results obtained are shown in Table 3. It is seen that the samples of the invention show excellent quality for the superimposed letter. TABLE 3

EXAMPLE 4

Emulsions for photographic layers, a dispersion of zinc hydroxide, a dispersion of activated carbon, a dispersion of an electron transmitting agent, dispersions of yellow, magenta and cyan couplers and a dispersion for an interlayer were prepared as described below. Then, a photographic material (sample 401) was prepared using these materials as described below. In addition, an image-receiving material was prepared as described below.

Emulsion for the blue-sensitive layer:

The following solution (1) and solution (2) were simultaneously added to a well-stirred aqueous gelatin solution (prepared by adding 20 g of gelatin, 3 g of potassium bromide, 0.03 g of the following compound (1) and 0.25 g of HO(CH2)2S(CH2)2(OH2)2OH to 800 cm3 of water and heating at 50°C) over a period of 30 minutes. Thereafter, the following solution (3) and solution (4) were added at the same time over a period of 20 minutes. 5 minutes after initiating the addition of solution (3), a dye solution described below was added over a period of 18 minutes.

After washing with water and desalting, 20 g of lime-treated ossein gelatin was added to the mixture and the pH was adjusted to 6.2 and the pAg to 8.5. Then, sodium thiosulfate, 4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene and chloroauric acid were added for optimum chemical sensitization to obtain 600 g of a monodisperse cubic silver chlorobromide emulsion with an average grain size of 0.40 µm.

Solution (1):

AgNO3 (g) 30 g

Water to 180 cm³

Solution (2):

Kbr (g) 17.8 g

NaCl (g) 1.6 g

Water to 180 cm³

Solution (3):

AgNO3 (g) 70 g

Water to 350 cm³

Solution (4):

Kbr (g) 49 g

Water to 350 cm³

Dye solution:

The following dyes were dissolved in 160 cm³ of methanol. Connection (1):

Emulsion for the green-sensitive layer:

The following solutions (I) and (II) were added over a period of 30 minutes to the aqueous gelatin solution shown below which was well stirred and heated at 50°C. Then, solutions (III) and (IV) were added over a period of 30 minutes, and then the dye solution described below was added 1 minute after completion of the addition of solutions (III) and (IV).

Gelatin solution:

Gelatine 20g

NaCl69

KBr 0.3 g

Water 730ml

Solution (I):

AgNO3 50 g

Water to 200 cm³

Solution (II):

KBr 21 g

NaCl 6.9g

Water to 200 cm³

Solution (III)

AgNO3 50 g

Water to 200 cm³

Solution (IV):

KBr 28 g

NaCl 3.5g

Water to 200 cm³ Composition of the dye solution:

Methanol 154 cm³

After washing with water and desalting, 20 g of gelatin were added, the pH and pag were adjusted, and triethylthiourea, chloroauric acid and 4-hydroxy-6-methyl-1,3,3a,7- tetraazaindene were added for optimal chemical sensitization.

Emulsion for the red-sensitive layer:

The following solutions (I) and (II) were added to a well-stirred aqueous gelatin solution (prepared by adding 20 g of gelatin, 0.3 g of potassium bromide, 6 g of sodium chloride and 30 mg of the following compound (A) to 800 ml of water and heating at 50°C) at the same time and at the same flow rate over a period of 30 minutes. Thereafter, the following solutions (III) and (IV) were also added at the same time over a period of 30 minutes. 3 minutes after initiating the addition of the solutions (III) and (IV), the dye solution described below was added over a period of 20 minutes.

After washing with water and desalting, 22 g of lime-treated ossein gelatin was added and the pH was adjusted to 6.2 and the pag to 7.7. Then, sodium thiosulfate, 4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene and chloroauric acid were added for optimum chemical sensitization at 60°C to obtain a monodisperse cubic silver chlorobromide emulsion with an average grain size of 0.38 µm. The yield of the emulsion was 635 g.

Solution (I)

AgNO3 50.0 g

Water to 200 ml

Solution (II):

KBr 28.4 g

NaCl 3.4g

Water to 200 ml

Solution (III):

AgNO3 50.0 g

Water to 200 ml

Solution (IV):

KBr 35.0 g

Water to 200 ml Connection (A):

Dye solution:

67 mg of the following dye (a) and 133 mg of the following dye (b) were dissolved in 100 ml of methanol. Dye (a) Dye (b)

Then, a dispersion of zinc hydroxide was prepared as described below. 12.5 g of zinc hydroxide with an average grain size of 0.2 µm, 1 g of carboxymethyl cellulose as a dispersant and 0.1 g of sodium polyacrylate were added to 100 cm3 of a 4% aqueous gelatin solution and ground for 30 minutes with glass beads with an average grain size of 0.75 mm. The glass beads were then removed to obtain a dispersion of zinc hydroxide.

A dispersion of activated carbon was prepared by adding 2.5 g of activated carbon powder (special grade, product of #Wako Pure Chemical), 1 g of Demole N (manufactured by Kao Soap Co.) as a dispersant and 0.25 g of polyethylene glycol nonylphenyl ether to 100 cc of a 5% aqueous gelatin solution and then grinding for 120 minutes with glass beads having an average grain size of 0.75 mm. After removing the glass beads, a dispersion of activated carbon having an average grain size of 0.5 µm was obtained.

An electron transmitting agent dispersion was prepared by adding 10 g of an electron transmitting agent shown below, 0.5 g of polyethylene glycol as a dispersant and 0.5 g of an anionic surfactant described below to a 5% aqueous gelatin solution, followed by grinding for 60 minutes with glass beads having an average grain size of 0.75 mm. After removing the glass beads, an electron transmitting agent dispersion having an average grain size of 0.3 µm was obtained. Electron-transfer agent: Anionic surfactant:

Gelatin dispersions, each containing a compound for the creation of a dye, were prepared as described below.

A yellow, magenta or cyan dye-forming composition as shown below was added to 50 cc of ethyl acetate and dissolved under heating at about 60°C to form a uniform solution. The resulting solution was mixed with 100 g of an aqueous 10% lime-processed gelatin solution, 0.6 g of sodium dodecylbenzenesulfonate and 50 cc of water by stirring and then dispersed for 10 minutes with a homogenizer at 10,000 rpm. The dispersion thus prepared was referred to as a gelatin dispersion of a dye-forming compound. Compound (1) for the creation of a dye: Compound (2) for the creation of a dye: Compound (3) for the creation of a dye: Electron-donating compound (1): Solvent (2) with high boiling point: Electron-transmitting precursor (3) Connection A:

A gelatin dispersion of the electron donating compound (4) for an interlayer was prepared as described below.

23.6 g of the following electron donating compound (4) and 8.5 g of the above-described high boiling point solvent (2) were added to 30 cc of ethyl acetate to form a uniform solution. The solution was mixed with 100 g of a 10% aqueous solution of lime-treated gelatin, 0.25 g of sodium hydrogen sulfite, 0.5 g of sodium dodecylbenzenesulfonate and 30 cc of water with stirring and then dispersed for 10 minutes with a honeycomb at 1000 rpm. The resulting dispersion was referred to as gelatin dispersion of electron donating compound (4). Electron-donating compound (4):

The constitution of sample No. 401 was as follows: Sixth layer: protective layer Coating amount (mg/m²)

Carrier:

Polyethylene terephthalate (96 µm thick) (carbon black was added to the back layer)

The compounds used are as follows: *1 Surfactant (5): *2 Surfactant (6): *3 Water soluble polymer: *4 Antifoggants (7): *5 Surfactant (8): *6 Surfactant (9): *7 Electron-transmitting agent (10):

*8 Hardeners (11):

1,2-bis(vinylsulfonylacetamide) *9 Antifoggants (12):

The composition of the image receiving material used here was as follows:

The compounds used above were as follows: Silicone oil (1): Surfactant (1): Surfactant (2): Surfactant (3): Surfactant (4):

Bleaching agents (1):

2, 5-Bis(5-tert-butylbenzoxazolyl(2))thiophen Surfactant (5):

Water-soluble polymer (1):

Sumicagel L 5-H (product of Sumitomo Chemical Co., Ltd.)

Water-soluble polymer (2):

Dextran (molecular weight: 70,000) Mordants (1): Solvent (1) with high boiling point: Hardener (1):

In the same manner as Sample No. 401 was prepared, Sample Nos. 402 to 406 were prepared as shown in Table 4 below. Sample Nos. 402 to 406 each contained a compound used in the invention dispersed in gelatin by an oil dispersion method in the second and fourth layers in an amount of 3 x 10-3 mol/m2, respectively.

The thus prepared samples Nos. 401 to 406 were exposed through an optical wedge using a spectrophotometric camera, whereby the optical density was continuously varied in the direction perpendicular to the wavelength.

The exposed samples were then wetted with water by applying hot water (35ºC) to the emulsion surface of each sample in an amount of 15 ml/m² for 3 seconds. The thus wetted sample was attached to a previously prepared image-receiving material so that the coated surfaces of the two were facing each other.

The combined sample was then heated with a hot roller for 15 seconds, after which the temperature of the wetted layer was adjusted to 78ºC. Then, the image-receiving material was peeled off from the photographic material, and as a result, a blue-green-red spectrographic image was obtained on the image-receiving layer in accordance with the wavelength of the exposure light.

The density of each of yellow, magenta and cyan colors was measured with a 310 type densitometer (manufactured by X-rite Co.). The results obtained are shown in Table 4 below. Table 4

From the above results, it can be found that the density of both blue, green and red colors increased by adding the compound of formula (I) used in the invention. In addition, the color purity is also increased by adding the compound of formula (I) used in the invention due to the decrease of the complementary components. Accordingly, it was proved that the compounds according to the invention had an excellent ability to improve color reproducibility.

Then, the above-described photographic material samples were preserved for 1 month under the condition of 30°C and 70% RH and then subjected to the same treatment. After the treatment, the same results as in Table 4 were obtained. Accordingly, it was confirmed that the compounds of formula (I) used in the invention do not adversely affect the storage life of the photographic materials containing the compound.

EXAMPLE 5

Each of the compounds I-11, I-17 and I-21 used in the invention was added to the timing layer of the cover sheet as in Example 1 in JP-A-63-289551 in an amount of 0.825 mmol/m² to prepare cover sheet samples (5-1), (5-2), (5-3) and (5-4). Each of these cover sheets was attached to the photosensitive sheet (102) of the same sample and then processed in the same manner as in the same example. The liquid spraying temperature was 10°C, 25°C and 35°C.

As a result, it was found that all the samples showed a low processing temperature dependence and had excellent photographic properties with a high Dmax value and a low Dmin value.

EXAMPLE 6

Each of the compounds I-12 and I-36 used in the invention was added to each of the 3rd, 4th, 6th, 7th, 9th and 10th layers of Sample 102 described in Example 1 in JP-A-01-112241 in an amount of 3 mg/m² to prepare Sample Nos. 6-1 and 6-2. Each of these samples was then treated and dried in the same manner as for the same Example above. described and were found to be excellent in color reproducibility.

EXAMPLE 7

The compound I-14 according to the invention was added to each of the 3rd, 4th, 6th, 7th, 11th and 12th layers of Sample No. 502 as in Example 4 of EP-A-327 066 in an amount of 3 mg/m² per layer to prepare Sample No. 9-1. The resulting sample was developed in the same manner as in the same Example described above and was found to be excellent in color reproducibility.

EXAMPLE 8

The compound 1-12 used in the invention was added to the emulsion layer of Sample No. 1 as described in Example 1 of JP-A-01-234840 in an amount of 560 mg per 1 mol of silver halide to prepare Sample No. 10-1. The resulting sample was prepared in the same manner as described above for the same example and was found to be excellent in density and image quality.

While the invention has been described in detail with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the scope of the invention.

Claims (13)

1. A silver halide photographic material comprising a silver halide emulsion and a compound represented by formula (I): wherein R represents an aliphatic group, an aromatic group, or a heterocyclic group, and Z represents an atomic group necessary to form a nitrogen-containing aromatic heterocyclic group, the aromatic heterocyclic ring being selected from the group consisting of pyrrole, imidazole, pyrazole, 1,2,3-triazole, 1,2,4-triazole, benzotriazole, tetrazole, thiazoline-2-thione, thiazoline-2-one, oxazoline-2-thione, 1,2-oxazoline-5-thione, 1,2-thiazoline-5-thione, 1,2-oxazoline-5-one, 1,2-thiazoline-5-one, tetrazolin-2-thione, 1,3,4-thiadiazoline-2-thione, 1,3,4-thiadiazoline-2-one, 1,3,4-oxadiazolin-2-thione, 1,3,4-oxadiazolin-2-one, 1,2,4-triazolin-3-thione, dihydropyridin-2-thione, dihydropyridin-2-one, isomdol, indole, indazole, benzimidazole, benzimidazol-2-thione, benzimidazol-2-one, benzoxazolin-2-thione, benzoxazolin-2-one, benzothiazolin-2-thione, benzothiazolin-2-one, purine, pyrazolopyridines, and pyrazolopyrimidines, wherein the nitrogen-containing heterocyclic aromatic group which is in formula (I) or each substituent of this group is substituted with at least one nitro group, and wherein R contains a ballast group or a group capable of accelerating the adsorption of the compound onto silver halide. 2. A silver halide photographic material according to claim 1, wherein the material also contains a hydrazine compound represented by the general formula (III): wherein R₃₁ represents an aliphatic group or an aromatic group; R₃₂ represents a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an amino group, a carbamoyl group or a cyclocarbonyl group; G₁ represents a carbonyl group, a sulfonyl group, a sulfoxy group, a group or an iminoethylene group, and A₁ and A₂ represent hydrogen atoms, or one represents a hydrogen atom and the other represents a substituted or unsubstituted alkylsulfonyl group, a substituted or unsubstituted arylsulfonyl group, or a substituted or unsubstituted acyl group. 3. The silver halide photographic material according to claim 2, wherein R₃₁ represents an aryl group. 4. A silver halide photographic material according to claim 2, wherein A₁ and A₂ are hydrogen atoms. 5. The silver halide photographic material of claim 2, wherein G1 represents a carbonyl group. 6. A silver halide photographic material according to claim 2, wherein the photographic material also contains a negative-working emulsion. 7. The silver halide photographic material according to claim 2, wherein the compound represented by formula (I) is contained in an inner latent image type silver halide emulsion layer or in a hydrophilic colloidal layer adjacent to the inner latent image type silver halide emulsion layer. 8. The silver halide photographic material according to claim 1, wherein R represents an aromatic group. 9. The silver halide photographic material according to claim 1, wherein the group represented by R contains a group which accelerates adsorption onto silver halide. 10. The silver halide photographic material according to claim 1, wherein the group represented by R contains a ballast group. 11. A silver halide photographic material according to claim 1, wherein the nitrogen-containing heterocyclic aromatic ring which is in formula (I) is selected from the group consisting of pyrrole, imidazole, pyrazole, triazole, tetrazole, thiazoline-2-thione, oxazoline-2-thione, indole, indazole, benzimidazole, 1,3,4-thiadiazoline-2-thione, tetrazoline-5-thione, 1,3,4-oxadiazoline-2-thione, 1,2,4-triazoline-3-thione and pyrazolopyridines. 12. A silver halide photographic material according to claim 1, wherein the nitrogen-containing heterocyclic aromatic ring which is in formula (I) is a ring containing pyrazole nuclei selected from the group consisting of pyrazole, indazole and pyrazolopyridine. 13. The silver halide photographic material of claim 1, wherein the nitrogen-containing heterocyclic ring formed by Z and N in formula (I) is pyrazole, indole, indazole, benzimidazole, benzimidazole-2-thione, benzoxazoline-2-thione, benzothiazolin-2-one or a pyrazolopyridine.