DE3924571A1 - Direct positive silver halide emulsion contg. organic desensitiser - with heterocyclic azulene gp. and methine dyestuff, giving high speed and stability - Google Patents

Abstract

Direct positive Ag halide (AgX) emulsion contains a light-sensitive AgX, a binder, methin dyestuff(s) (I) and an organic desensitiser (II) with a redn. potential at least as positive as -1.0V vs. SCE. (I) has a heterocyclic azulene gp., contg. N or chalcogen atom(s) as heteroatom. The 7-membered ring in the heterocyclic azulene gp. forms a chromophoric conjugated resonance unit with the 10 pi electron system of the azulene and the methin gp. has an auxochromic substit. USE/ADVANTAGE - The emulsion is claimed for use in photographic material. It is faster than usual, without increased Dmin, and the change in speed in Dmin during storage before exposure is small.

Description

The present invention relates to pre-fogged direct positive silver halide emulsions, the methine dyes and organic desensitizers direct positive Silver halide emulsions, the improved photographic Have properties.

Spectral sensitization techniques for pre-fogged direct positive silver halide emulsions are important techniques, viewed from the point of view of preparing highly sensitive photographic materials. The dyes used in the spectral sensitization of pre-fogged direct positive silver halide emulsions are generally referred to as desensitizing dyes, and many such compounds are known, e.g. Cyanine, merocyanine dyes and the like (TH James, Theory of the Photographic Process, 3rd Ed., Macmillan 1966, NY, 198-228). Preferably, its reduction potential is 1.2 (V _vs SCE) or a more positive value than this.

It is known that these desensitizing dyes either individually or in combination (for example with organic Desensitizers).

Several conditions must be met by the desensitizing dyes used in these photographic materials. For example, a high spectral sensitivity must be obtained; likewise, the minimum density (D _min ) at the inversion (exposed portion) must not increase, and changes in the photographic speed and minimum density (D _min ) must be small during storage of the raw materials.

Sufficiently satisfactory properties, however, are not obtained, even when using conventional Desensitizing dyes and organic desensitizers. The present inventors have found that Methine dyes satisfy the above conditions, when used as desensitizing dyes or organic Desensitizers are used, and have earlier Patent pending (JP-A-63-210922, corresponding to US 48 14 265). The present invention relates to a Improvement of it. The term "JP-A" as used herein means a "published, unaudited, Japanese Patent application ".

It is an object of the present invention to provide pre-fogged, direct-positive silver halide emulsions having higher photographic speeds, in which there is no increase in minimum density (D _min ) and in which the changes in photographic speed and minimum density (D _min ) caused by Storage before exposure are caused to be small.

It has now been found that these and other objects of the present invention are achieved by a direct positive silver halide emulsion containing a photosensitive silver halide, a binder, at least one methine dye having a heterocyclic azulene group containing as heteroatom at least one nitrogen or a chalcogen, wherein the 7-membered ring containing the 10 pi electron system of the heterocyclic azulene group contained in the heterocyclic azulene group forms a conjugated coloring resonance unit, and wherein the methine dye on the methine bond is substituted with an auxochromic group, and at least one organic desensitizing compound having a reduction potential equal to or more positive than -1.0 V _VS SCE.

The invention will be explained in more detail below.

This methine dye acts as a desensitizing dye or organic desensitizer and is used together with at least one organic desensitizer having a reduction potential of -1.0 (V _VS SCE) or a positive value thereof.

The preferred heterocyclic Azulenkern for the Methin dyes used in the invention, the heterocyclic azulene nuclei is a  Core in which at least one of the carbon atoms in the 1- or 3-position through a chalcogen or nitrogen atom has been substituted.

The dyes of the present invention may be characterized by a alternating resonance form, such as formula (I); and here is the use of each resonance form the also include other resonance form.

In the formula, V₁, V₂, V₃, V₄, V₅ and V₆, the same or may be different, each hydrogen, a Halogen atom, an alkyl, acyl, acyloxy, alkoxycarbonyl, Carbamoyl, sulfamoyl, carboxyl, cyano, hydroxy, amino, Acylamino, alkoxy, alkylthio, alkylsulfonyl, sulfonic acid or aryl group, provided that at least one V₂ to V₆ represents a group, which by a  Methine carbon group (L) is formed, which the heterocyclic azulene group with the auxochromic group (E) connects, and that each of two V₂ to V₆, to adjacent carbon atoms are bound to form a condensed ring can be connected. Further may have these further substituents (eg. Halogen atoms, cyano, alkoxycarbonyl, carbamoyl groups, etc.).

Y and Z₂, which may be the same or different, mean each

wherein V has the same definition as V₁, a Chalcogen atom (eg, an oxygen, sulfur, selenium, and Tellurium atom) or

There are cases where R₃ is needed and cases where it is not needed to form a nucleus, and if so is required, R₃ is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted Aryl or a heterocyclic group or a salt thereof, provided that at least one Y and Z₂ another Mean group as a carbon atom. Further, if Y and Z₂ each represents oxygen or nitrogen, at least one of them is a nitrogen atom. If further one Oxygen and the other represent carbon or nitrogen, Z₂ is oxygen and Y is carbon or nitrogen.

M represents a counterion to the charge balance, and m is 0 or an integer necessary for charge balancing.

In formula (I), preferably V₂, V₅ or V₆, and  particularly preferably V₂ or V₆, the group L and E represents.

The auxochrome group E will now be explained in detail.

E may have any desired general formula, which may be found in Methine dyes is found. Typically, the auxochrome group nitrogen or oxygen atoms, and within the dye there is resonance between one electrostatic and a non-electrostatic state. For example, it can be in the form of any auxochromic Present in cyanine, merocyanine, oxonol, Pyrrylium or thiapyrylium dyes occurs. The However, the auxochrome group is in the present invention not limited to such groups. Although not as common are auxochrome groups with other atoms, such as phosphorus or boron, also included in the present invention, z. B. 2-Triphenylphosphor-1,3-cyclopentadien-5-yl.

The group L and E of the formula (I) is preferably represented by formulas (II) to (IX), provided that the formula (VII) represents a methine dye.

In the formula, Q₁ represents an atomic group necessary to form a 5- or 6-membered nitrogen-containing ring; L₁, L₂, L₃, L₄ and L₅ each represent substituted or unsubstituted methine groups; R₄ represents a substituted or unsubstituted alkyl group, l ₁ is 0 or an integer of 1 to 3; and n ₁ is 0 or 1.

In the formula, Q₂ represents an atomic group necessary to form a 5- or 6-membered nitrogen-containing ring; L₆, L₇, L₈, L₉ and L₁₀ each represent a substituted or unsubstituted methine group; R₅ represents a substituted or unsubstituted alkyl group, l ₂ is 0 or an integer of 1 to 3; and n ₂ is 0 or 1.

In the formula, Y 'has the same definition as Y; Z₂ 'has the same definition as Z₂; V₁ ', V₂', V₃ ', V₄' and V₅ 'each have the same definitions as V₁; L₁₁, L₁₂ and L₁₃ each represents a substituted or unsubstituted methine group; and l ₃ is 0 or an integer of 0 to 3;

In the formula, D₁ and D₁ 'each represent a cyclic or acyclic atomic group necessary to form an acidic nucleus; L₁₄, L₁₅, L₁₆ and L₁₇ each represent a substituted or unsubstituted methine group; l ₄ is 0 or an integer from 1 to 3; and n ₃ is 0 or 1.

In the formula, R₆ and R₇, which may be the same or different, each represents a substituent known in general tertiary amines, and R₆ and R₇ may be connected in a ring; L₁₈ and L₁₉ are each a substituted or unsubstituted methine group; and l ₅ is 0 or an integer from 1 to 3.

In the formula, at least one E and E 'represents E₁, and the other represents E₁ or E₂; V₁ to V₆, Y, Z₂, M and m have the same definitions as in formula (I), provided that at least one V₂ to V₆ represents the bond to L₂₀ or L₂₄; W₁ represents an atomic group necessary to form a 5- or 6-membered heterocyclic ring; R₈ represents hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl or a heterocyclic group; Q₃ and R₉ have the same definitions as Q₁ and R₄ in formula (II). L₂₀, L₂₁, L₂₂, L₂₃, L₂₄, L₂₅ and L₂₆ have the same definition as L₁; l ₆ and l ₇ are each 0 or an integer of 1 to 3; and n ₄ is 0 or 1.

In the formula W₂ has the same definition as W₁; R₁₀ has the same definition as R₈ in formula (VII); D₂ and D₂ 'have the same definition as D₁ and D₁' in formula (V); L₂₇, L₂₈, L₂₉, L₃₀, L₃₁ and L₃₂ have the same definition as L₁; l ₈ and l ₉ are each 0 or an integer of 1 to 3; and n ₅ is 0 or 1.

In the formulas L₃₃ and L₃₄ have the same definition as L₁; Ar represents an aromatic group; l ₁₀ is 0 or an integer from 1 to 3.

The compounds represented by the formulas (I) to (IX) are described below in more detail.

R₃ is preferably a hydrogen atom, an unsubstituted one Alkyl group with 18 or fewer carbon atoms (eg. Methyl, ethyl, propyl, butyl, pentyl, octyl, decyl, dodecyl or octadeyl) or a substituted alkyl group, e.g. B. an alkyl group having 18 or less carbon atoms, the has been substituted with, for example, carboxy, sulfo, Cyano, halogen atoms (eg fluorine, chlorine or bromine), hydroxyl, Alkoxycarbonyl having 8 or fewer carbon atoms (eg. Methoxycarbonyl, ethoxycarbonyl, phenoxycarbonyl, Benzyloxycarbonyl), alkoxy groups of 8 or less  Carbon atoms (eg methoxy, ethoxy, benzyloxy, phenethyloxy), monocyclic aryloxy having 10 or less carbon atoms (eg, phenoxy, p-tolyloxy), acyloxy with 3 or less Carbon atoms (eg acetyloxy, propionyloxy), acyl with 8 or fewer carbon atoms (eg acetyl, propionyl, Benzoyl, mesyl), carbamoyl (e.g., carbamoyl, N, N-dimethylcarbamoyl, Morpholino carbonyl, piperidinocarbonyl), sulfamoyl groups (e.g. Sulfamoyl, N, N-dimethylsulfamoyl, morpholinosulfonyl, piperidinosulfonyl, aryl with 10 or fewer carbon atoms (eg phenyl, 4-chlorophenyl, 4-methylphenyl, alpha-naphthyl) aryl (e.g. Phenyl, 2-naphthyl); substituted aryl (eg 4-carboxyphenyl, 4-sulfophenyl, 3-chlorophenyl, 3-methylphenyl); and heterocyclic groups (eg, 2-pyridyl, 2-thiazolyl).

Unsubstituted alkyl groups (eg, methyl, ethyl) and Sulfoalkyl groups (eg, 2-sulfoethyl, 3-sulfopropyl, and 4-sulfobutyl) are particularly preferred R₃ groups. Methyl groups are further preferred.

Furthermore, alkali metals are particularly preferred metal atoms, the salts with R₃ can form, and pyridines and amines are preferred organic compounds, the salts with R₃ can form.

Preferred V₁, V₂, V₃, V₄, V₅, V₆, V₁ ', V₂', V₃ ', V₄' and V₅ 'groups include hydrogen, halogen (eg, chlorine, Fluorine, bromine), unsubstituted alkyl of 10 or less Carbon atoms (eg, methyl, ethyl), substituted alkyl with 18 or fewer carbon atoms (eg benzyl, alpha-naphthylmethyl, 2-phenylethyl, trifluoromethyl), acyl with 10 or fewer carbon atoms (eg acetyl, benzoyl, Mesyl), acyloxy of 10 or fewer carbon atoms (e.g.  Acetyloxy), alkoxycarbonyl of 10 or less Carbon atoms (eg methoxycarbonyl, ethoxycarbonyl, Benzyloxycarbonyl), substituted or unsubstituted Carbamoyl (eg carbamoyl, N, N-dimethylcarbamoyl, Morpholinocarbonyl, piperidinocarbonyl), substituted or unsubstituted sulfamoyl (eg, sulfamoyl, N, N-dimethylsulfamoyl, Morpholinosulfonyl, piperidinosulfonyl), carboxy, cyano, Hydroxyl, amino, acylamino having 8 or less carbon atoms (eg acetylamino), alkoxy with 10 or less Carbon atoms (eg methoxy, ethoxy, benzyloxy), Alkylthio (e.g., ethylthio), alkylsulfonyl (e.g. Methylsulfonyl groups), sulfonic acid and aryl (eg phenyl, Tolyl). Further, each of two V₂ to V₆, to adjacent carbon atoms are bonded, together one Form benzene ring. Furthermore, they can be connected to form a heterocyclic ring (eg, a pyrrole, Thiophene, furan, pyridine, imidazole, triazole, thiazole ring).

Hydrogen atoms are preferred as V₂, V₃, V₄, V₅, V₆, V₂ ', V₃ ', V₄' and V₅ '. Hydrogen, chlorine, alkoxy (eg methoxy), Alkylthio (eg methylthio) and aryl (eg phenyl) are for V₁ and V₁ 'preferred.

M _m is included in the formula to indicate the presence of cations or anions or their absence to neutralize the ionic charge of the dye. Whether a given dye is cationic or anionic or has a net ionic charge depends on the auxochromic group and the substituent. The counterion can be easily exchanged after the dye has been prepared. Typical cations are ammonium ions and alkali metal ions, while anions may be specific inorganic or organic anions, including e.g. Halogenated anions (e.g., fluoro, chloro, bromo and iodo ions), substituted arylsulfonate ions (e.g., p-toluenesulfonate, p-chlorobenzenesulfonate ion), aryl disulfonate ion (e.g., 1,3-benzenedisulfonate, 1,5-naphthalenedisulfonate, 2,6-naphthalene disulfonate ion), alkyl sulfation (e.g., methyl sulfate ion), sulfate, thiocyanate, perchlorate, tetrafluoroborate, picrate, acetate, and trifluoromethanesulfonate ion. Iodion ions are preferred.

Of the cores formed by Q₁ and Q₃ are preferably a thiazole nucleus (eg thiazole, 4-methylthiazole, 4-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole), Benzothiazole nucleus (eg, benzothiazole, 4-chlorobenzothiazole, 5-chlorobenzothiazole, 6-chlorobenzothiazole, 5-nitrobenzothiazole, 4-methylbenzothiazole, 5-methylbenzothiazole, 6-methylbenzothiazole, 5-bromobenzothiazole, 6-bromobenzothiazole, 5-iodobenzothiazole, 5-phenylbenzothiazole, 5-methoxybenzothiazole, 6-methoxybenzothiazole, 5-ethoxybenzothiazole, 5-ethoxycarbonylbenzothiazole, 5-carboxybenzothiazole, 5-phenethylbenzothiazole, 5-fluorobenzothiazole, 5-chloro-6-methylbenzothiazole, 5,6-dimethylbenzothiazole, 5,6-dimethoxybenzothiazole, 5-hydroxy-6-methylbenzothiazole, Tetrahydrobenzothiazole, 4-phenylbenzothiazole, Naphthothiazole nucleus (e.g., naphtho [2,1-d] thiazole, 5-methoxynaphtho [1,2-d] thiazole, 7-ethoxynaphtho [2,1-d] thiazole, 8-methoxynaphtho [2,1-d] thiazole, 5-methoxynaphtho [2,3-d] thiazole), Thiazoline nucleus (eg, thiazoline, 4-methylthiazoline, 4-nitrothiazoline), oxazole nucleus (e.g., oxazole, 4-methyloxazole, 4-nitrooxazole, 5-methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole), benzoxazole nucleus (e.g.  Benzoxazole, 5-chlorobenzoxazole, 5-methylbenzoxazole, 5-bromobenzoxazole, 5-fluorobenzoxazole, 5-phenylbenzoxazole, 5-methoxybenzoxazole, 5-nitrobenzoxazole, 5-trifluoromethylbenzoxazole, 5-hydroxybenzoxazole, 5-carboxybenzoxazole, 6-methylbenzoxazole, 6-chlorobenzoxazole, 6-nitrobenzoxazole, 6-methoxybenzoxazole, 6-hydroxybenzoxazole, 5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, 5-ethoxybenzoxazole), naphthooxazole nucleus (e.g. Naphtho [2,1-d] oxazole, naphtho [1,2-d] oxazole, Naphtho [2,3-d] oxazole, 5-nitronaphtho [2,1-d] oxazole), Oxazoline nucleus (eg, naphtho [4,4-dimethyl] oxazoline), Selenazole nuclei (eg 4-methylselenazole, 4-nitroselenazole, 4-phenylselenazole), benzoselenazole nucleus (e.g., benzoselenazole, 5-chlorobenzoselenazole, 5-nitrobenzoselenazole, 5-methoxybenzoselenazole, 5-hydroxybenzoselenazole, 6-nitrobenzoselenazole, 5-chloro-6-nitrobenzoselenazole, 5,6-dimethylbenzoselenazole), naphthoselenazole nucleus (e.g. Naphtho [2,1-d] selenazole, naphtho [1,2-d] selenazole), Selenazoline nucleus (eg, selenazoline, 4-methylselenazoline), Tellurazole nucleus (eg tellurazole, 4-methyltellurazole, 4-phenyltellurazole), benzotellurazole nucleus (e.g., benzotellurazole, 5-chlorobenzotellurazole, 5-methylbenzotellurazole, 5,6-dimethylbenzotellurazole, 6-methoxybenzotellurazole), Naphthotellurazole nucleus (eg naphtho [2,1-d] tellurazole, Naphtho [1,2-d] tellurazole), tellurazole nucleus (eg tellurazoline, 4-methyltellurazoline), 3,3-dialkylindolenine nucleus (e.g. 3,3-dimethylindolenine, 3,3-diethylindolenine, 3,3-dimethyl-5-cyanoindolenine, 3,3-dimethyl-6-nitroindolenine, 3,3-dimethyl-5-nitroindolenine, 3,3-dimethyl-5-methoxyindolenine, 3,3,5-trimethylindolenine, 3,3,5-trimethyl-5-chloroindolenine), Imidazole nucleus (eg 1-alkylimidazole, 1-alkyl-4-phenylimidazole), Benzoimidazole nucleus (eg 1-alkylbenzoimidazole,  1-alkyl-5-chlorobenzoimidazole, 1-alkyl-5,6-dichlorobenzoimidazole, 1-alkyl-5-methoxybenzoimidazole, 1-alkyl-5-cyanobenzoimidazole, 1-alkyl-5-fluorbenzoimidazol, 1-alkyl-5-trifluormethylbenzoimidazol, 1-alkyl-6-chloro-5-cyanobenzoimidazol, 1-alkyl-6-chloro-5-trifluormethylbenzoimidazol, 1-allyl-5,6-dichlorbenzoimidazol, 1-allyl-5-chlorobenzoimidazole, 1-arylimidazole, 1-arylbenzoimidazole, 1-aryl-5-chlorobenzoimidazole, 1-aryl-5,6-dichlorobenzoimidazole, 1-aryl-5-methoxybenzoimidazole, 1-aryl-5-cyanobenzoimidazole), naphthoimidazole nucleus (e.g. 2-alkylnaphtho [1,2-d] imidazole, 1-arylnaphtho [1,2-d] imidazole) and groups in which the above alkyl groups are 1 to 8 Carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl and other such unsubstituted alkyl groups, as well as Hydroxyalkyl groups (eg 2-hydroxyethyl, 3-hydroxypropyl) respectively. Methyl and ethyl groups are particularly preferred Alkyl groups in their compounds. The aforementioned Aryl groups include phenyl, by halogen (eg, chlorine) substituted phenyl substituted by alkyl (e.g., methyl) Phenyl and phenyl substituted by alkoxy (e.g., methoxy) on.

Also possible are the pyridine (eg 2-pyridine, 4-pyridine, 5-methyl-2-pyridine, 3-methyl-4-pyridine), quinoline (e.g. 2-quinoline, 3-methyl-2-quinoline, 5-ethyl-2-quinoline, 6-methyl-2-quinoline, 6-nitro-2-quinoline, 8-fluoro-2-quinoline, Methoxy-2-quinoline, 6-hydroxy-2-quinoline, 8-chloro-2-quinoline, 4-quinoline, 6-ethoxy-4-quinoline, 6-nitro-4-quinoline, 8-chloro-4-quinoline, 8-fluoro-4-quinoline, 8-methyl-4-quinoline, 8-methoxy-4-quinoline, 6-methyl-4-quinoline, 6-methoxy-4-quinoline, 6-chloro-4-quinoline),  Isoquinoline (e.g., 6-nitro-1-isoquinoline, 3-4-dihydro-1-isoquinoline, 6-nitro-3-isoquinoline), imidazo [4,5-b] quinoxaline (eg, 1,3-diethylimidazo [4,5-b] quinoxaline, 6-chloro-1,3-diarylimidazo [4,5-b] quinoxaline), oxadiazole, Thiadiazole, tetrazole and pyrimidine nucleus.

More preferred cores formed by Q₁ and Q₃ are the benzothiazole, benzoxazole and indolenine nucleus.

R₄, R₅ and R₉ can the quaternized substituents of a basic nucleus of any desired cyanine dye form.

For example, preferred R₄, R₅ and R₉ groups include unsubstituted alkyl having 18 or less carbon atoms (eg, methyl, ethyl, propyl, butyl, pentyl, octyl, decyl, Dodecyl, octadecyl) or substituted alkyl (preferably Alkyl of 18 or fewer carbon atoms) with carboxyl, sulfo, cyano, halogen (eg fluorine, chlorine, Bromine), hydroxyl, alkoxycarbonyl of 8 or less Carbon atoms (eg methoxycarbonyl, ethoxycarbonyl, Phenoxycarbonyl, benzyloxycarbonyl), alkoxy with 8 or less carbon atoms (eg, methoxy, ethoxy, benzyloxy, Phenethyloxy), monocyclic aryloxy of 10 or less Carbon atoms (eg phenoxy, p-tolyloxy), acyloxy with 3 or less carbon atoms (eg acetyloxy, propinyloxy), Acyl with 8 or fewer carbon atoms (eg acetyl, Propynyl, benzoyl, mesyl), carbamoyl (e.g., carbamoyl, N, N-dimethylcarbamoyl, morpholinocarbonyl, Piperidinocarbonyl), sulfamoyl (e.g., sulfamoyl, N, N-dimethylsulfamoyl, morpholinosulfonyl, piperidinosulfonyl), Aryl having 10 or fewer carbon atoms (eg, phenyl,  4-chlorophenyl, 4-methylphenyl, alpha-naphthyl).

D₁ and D₁ 'as well as D₂ and D₂' represent atomic groups which belong to Education of acidic nuclei are necessary and they can be one acidic core of any conventional merocyanine dye form. Preferred D₁ and D₂ groups are cyano, sulfo or Carbonyl groups and D₁ 'and D₂' represent the remaining Atomic groups necessary for the formation of an acidic nucleus are.

When the acidic nucleus is acyclic, in other words D₁ and D₁ 'or D₂ and D₂' are independent groups, is the end of the methine bond is a group such as malononitrile, Alkylsulfonylacetonitrile, Cyanomethylbenzofuranylketon or Cyanomethylphenylketon.

D₁ and D₁ 'or D₂ and D₂' may be connected to a 5- or 6-membered heterocyclic ring Carbon, nitrogen and chalcogen (typically Oxygen, sulfur, selenium and tellurium) atoms. Preferably, D₁ and D₁ 'or D₂ and D₂' are connected to to complete the following cores.

2-pyrazolin-5-one, pyrazolidine-3,5-dione, imidazolin-5-one, Hydantoin, 2- or 4-thiohydantoin, 2-iminooxazolidin-4-one, 2-oxazolin-5-one, 2-thiooxazoline-2,4-dione, isooxazolin-5-one, 2-thiazolin-4-one, thiazolidin-4-one, thiazolidine-2,4-dione, Rhodanine, thiazolidine-2,4-dithione, isorhodanine, Indan-1,3-dione, thiophen-3-one, thiophen-3-one-1,1-dioxide, Indrin-2-one, indrin-3-one, indazolin-3-one, 2-oxoindazolinium, 3-Oxoindazolinium, 5,7-dioxo-6,7-dihydro [3,2-a] pyrimidine,  Cyclohexane-1,3-dione, 3,4-dihydroisoquinolin-4-one, 1,3-dioxane-4,6-dione, barbituric acid, 2-thiobarbituric acid, Chroman-2,4-dione; Indazolin-2-one or Pyrido [1,2-a] pyrimidine-1,3-dione nuclei.

More preferred are 1,3-dialkyl barbituric acid, 1,3-dialkyl-2-thiobarbituric acid and 3-alkylrhodanine (preferably with an unsubstituted alkyl group for the alkyl group).

Substituents bonded to the nitrogen atom (s) are that are contained in these nuclei are preferably hydrogen, alkyl groups having 1 to 18 Carbon atoms, preferably 1 to 7 and in particular preferably 1 to 4 carbon atoms (for example methyl, ethyl, Propyl, isopropyl, butyl, isobutyl, hexyl, octyl, dodecyl, Octadecyl), substituted alkyl groups, e.g. B. arylalkyl (eg. Benzyl, 2-phenylethyl), hydroxyalkyl (e.g., 2-hydroxyethyl, 3-hydroxypropyl), carboxyalkyl (e.g., 2-carboxyethyl, 3-carboxypropyl, 4-carboxybutyl, carboxymethyl), alkoxyalkyl (e.g., 2-methoxyethyl, 2- (2-methoxyethoxy) ethyl), sulfoalkyl (eg, 2-sulfoethyl, 3-sulfopropyl, 3-sulfobutyl, 4-sulfobutyl, 2- (3-sulfopropoxy) ethyl, 2-hydroxy-3-sulfopropyl, 3-sulfopropoxyethoxyethyl), sulfatoalkyl (e.g. 3-sulfatopropyl, 4-sulfatobutyl), substituted heterocyclic alkyl (eg 2- (pyrrolidin-2-one-1-yl) ethyl, Tetrahydrofurfuryl, 2-morpholinoethyl), 2-acetoxyethyl, Carbomethoxymethyl, 2-methanesulfonylaminoethyl, allyl, aryl (e.g., phenyl, 2-naphthyl), 2-naphthyl), substituted aryl (e.g. 4-carboxyphenyl, 4-sulfophenyl, 3-chlorophenyl, 3-methylphenyl), heterocyclic groups (e.g., 2-pyridyl, 2-thiazolyl).  

Since R₆ and R₇ are tertiary amine substituents which are in the Synthesis, they can be any conventional tertiary Amine substituent group.

R₆ and R₇ are identical or different and are preferably unsubstituted alkyl groups of 18 or less Carbon atoms (eg, methyl, ethyl, propyl, butyl, pentyl, Octyl, decyl, dodecyl, octadecyl) or substituted Alkyl groups (preferably alkyl groups with 18 or less Carbon atoms) substituted with e.g. Carboxyl, sulfo, Cyano, halogen (eg fluorine, chlorine, bromine), hydroxyl, Alkoxycarbonyl having 8 or fewer carbon atoms (eg. Methoxycarbonyl, ethoxycarbonyl, phenoxycarbonyl, Benzyloxycarbonyl), alkoxy having 8 or less carbon atoms (eg methoxy, ethoxy, benzyloxy, phenethyloxy), monocyclic aryloxy having 10 or less carbon atoms (eg, phenoxy, p-tolyloxy), acyloxy with 3 or less Carbon atoms (eg acetyloxy, propionyloxy), acyl with 8 or fewer carbon atoms (eg acetyl, propionyl, Benzoyl, mesyl), carbamoyl (e.g., carbamoxyl, N, N-dimethylcarbamoyl, morpholinocarbonyl, piperidinocarbonyl), Sulfamoyl (eg, sulfamoyl, N, N-dimethylsulfamoyl, Morpholinosulfonyl, piperidinosulfonyl), aryl with 10 or less carbon atoms (eg, phenyl, 4-chlorophenyl, 4-methylphenyl, alpha-naphthyl), cyano, alkoxy (e.g., methoxy, Ethoxy), aryloxy (eg phenoxy) and alkoxycarbonyl (e.g. Ethoxycarbonyl).

Further, R₆ and R₇ may be linked together to to form a heterocycle other than a is aromatic heterocycle.  

For example, pyrrolidine, piperidine, morpholine, Piperazine, tetrahydropyridine, dihydropyridine and Tetrahydroquinoline is preferred.

In particular, ethyl groups are preferred for R₆ and R₇.

Of the heterocyclic rings formed by Q₂ are, for example, a pyrrole, carbazole, indole, Pyrazole, pyrazolo [1,5-a] benzimidazole, pyrazolo [1,5-b] quinazolone and an indazole nucleus is preferred.

Further, the 5- or 6-membered heterocyclic ring, which is formed by W₁ and W₂, a ring, the unlike an oxo or thioxo group in one corresponding position of the by D₁ and D₁ 'or D₂ and D₂' is shown heterocycle.

For R₈ and R₁₀, the substituents which are capable of to the nitrogen atoms of the by D₁ and D₁ 'or D₂ and D₂' heterocycle shown to be bound mentioned above are preferred.

Ar is an aromatic group and aryl groups (eg. Phenyl, 3-chlorophenyl, naphthyl) are preferred.

L₁, L₂, L₃, L₄, L₅, L₆, L₇, L₈, L₉, L₁₀, L₁₁, L₁₂, L₁₃, L₁₄, L₁₅, L₁₆, L₁₇, L₁₈; L₁₉, L₂₀, L₂₁, L₂₂, L₂₃, L₂₄, L₂₅, L₂₆, L₂₇, L₂₈, L₂₉, L₃₀, L₃₁, L₃₂, L₃₃ and L₃₄ represent methine groups and may be substituted or unsubstituted Alkyl groups (eg, methyl, ethyl), substituted or unsubstituted aryl groups (eg, phenyl) or halogen atoms  (eg, chlorine, bromine), and they may further be substituted Rings with other methine groups or rings with auxochromic To form groups.

The organic densitizers used according to the invention are substances that possess the ability to free Capture electrons by irradiation within the Silver halide bodies are produced, and they provide Substances that are adsorbed by silver halides. Furthermore, they are defined as substances that are a vacant Have electron energy content minimum, the lower is the electron energy content of the power band the silver halide body. Preferably they provide Compounds that occupy a Have electron energy content maximum, the lower lies as the valence electron band of the grains.

The evaluation of the vacant electron energy content minimum, referred to herein, is performed by measuring the reduction potential. The measurement of the reduction potential is suitably carried out by secondary harmonic exchange polarography with phase discrimination. The details are described below: acetonitrile (spectral purity) purified with 4A-1/16 molecular sieve was used as the solvent, and normal tetrapropylammonium chlorate (specially prepared reagent for polarography) was used as the auxiliary electrolyte. Sample solutions were prepared by dissolving 10 ^-3 to 10 ^-5 mol / L of organic desensitizer in acetonitrile containing 0.1 M auxiliary electrolyte, and the oxygen was removed for more than 15 minutes using an argon pure argon gas (99.999%). which had been passed through a highly alkaline, aqueous Pyrogalol solution and calcium chloride before the measurements were begun. A mercury drop electrode was used as the working electrode, a saturated calomel electrode (SCE) as the reference electrode, and platinum as the counter electrode. The space between the reference electrode and the sample solution was connected through a Rugin tube filled with acetonitrile containing 0.1 M of the auxiliary electrolyte, and a Vicault glass was used in the solution connection part. The measurements were carried out at 25 ° C, with the tip of the Rugin tube and the tip of the mercury capillary from 5 to 8 mm apart. In addition, the measurement of the reduction potential by secondary harmonic exchange voltammetry with phase discrimination using platinum as the working electrode is described in Journal of Imaging Science, Vol. 30, pages 27 to 35 (1986).

The organic desensitizers used according to the invention are substances with a reduction potential of -1.0 (V _VS SCE) or more positive values than this. If the reduction potential is lower than -1.0 V _VS SCE, they do not work as desensitizers. Many such organic desensitizers are z. In US 30 23 102, 33 14 796, 29 01 351 and 33 67 778, GB 7 23 019, 6 98 575, 6 98 576, 8 34 839, 6 67 206, 7 47 681, 7 96 873, 8 75 887, 9 05 237, 9 07 367 and 9 40 152, FR 15 20 824, 15 18 094, 15 18 095, 15 20 819, 15 20 823, 15 20 821 and 15 23 626 and BE 7 22 457 and 7 22,594 and JP-B-43-13,167 and JP-B-43-14500 (the term "JP-B" as used herein means a "Japanese Examined Patent Publication").

The compounds represented by formula (X) or (XI) or (XII) are preferred as organic desensitizers.

In the formula, Z₁ represents an atomic group necessary to form a nitrogen-containing heterocycle; T₁ represents halogen, alkyl, acyl, acyloxy, acylamino, alkoxy, alkoxycarbonyl, carbamoyl, sulfamoyl, carboxyl, cyano, hydroxyl, amino, alkylthio, alkylsulfonyl, sulfonic acid, sulfonamide, aryl or a fused ring, and these may have further substituents, such as for V₁ to V₆ of formula (I) described; q ₁ is 1, 2 or 3; and r ₁ is 0, 1, 2 or 3.

In the formula, R₁ is hydrogen, alkyl, aryl or a heterocycle, and these may have further substituents as described for V₁ to V₆ of formula (I); T₂ has the same definition as T₁; q ₂ is 1, 2 or 3; and r₂ is 0, 1, 2 or 3.

In the formula, R₂ has the same definition as R₁; T₃ has the same definition as T₁; Q ₃ represents 1, 2 or 3; and R ₃ represents 0, 1, 2 or 3rd

The formulas (X), (XI) and (XII) will now be more detailed described.

Specific examples of nitrogenous heterocyclic Cores completed by Z₁ close z. B. 1,2,4-triazole, 1,3,4-oxadiazole, 1,3,4-thiadiazole, Tetraazaindene, pentaazaindene, triazaindene, benzthiazole, Benzimidazole, benzoxazole, pyrimidine, triazine, pyridine, Quinoline, quinazoline, phthalazine, quinoxaline, Imidazole [4,5-b] quinoxaline, tetrazole and 1,3-diazaazulene a, and these rings can have further substituents, and they can be condensed. Preferred T₁, T₂- and T₃ groups include halogen (e.g., chlorine, fluorine, bromine), unsubstituted alkyl having 10 or less carbon atoms (eg, methyl, ethyl), substituted alkyl with 18 or less carbon atoms (eg cyclohexyl, allyl, benzyl, alpha-naphthylmethyl, 2-phenylethyl, trifluoromethyl), Acyl with 10 or fewer carbon atoms (eg acetyl, Benzoyl, mesyl), acyloxy of 10 or less Carbon atoms (eg acetyloxy), alkoxycarbonyl with 10  or less carbon atoms (eg methoxycarbonyl, Ethoxycarbonyl, benzyloxycarbonyl), substituted or unsubstituted carbamoyl (e.g., carbamoyl, N, N-dimethylcarbamoyl, morpholinocarbonyl, piperidinocarbonyl), substituted or unsubstituted sulfamoyl (e.g. Sulfamoyl, N, N-dimethylsulfamoyl, morpholinosulfonyl, Piperidinosulfonyl), carboxyl, cyano, hydroxyl, amino, Acylamino with 8 or fewer carbon atoms (eg. Acetylamino), alkoxy of 10 or fewer carbon atoms (eg methoxy, ethoxy, benzyloxy), alkylthio (eg ethylthio), Alkylsulfonyl (eg methylsulfonyl), sulfonic acid, Sulfonamido and aryl (eg, phenyl, tolyl). Two each of these substituents adjacent to one another Carbon atoms are bonded to a benzene ring be connected. Furthermore, they can also become one Heterocycle (eg, pyrrole, thiophene, furan, Pyridine, imidazole, triazole, thiazole).

R₁ and R₂ are preferably hydrogen, alkyl of 1 to 18, preferably 1 to 7 and particularly preferred 1 to 4 Carbon atoms (eg, methyl, ethyl, propyl, isopropyl, Butyl, isobutyl, hexyl, oxtyl, dodecyl, octadecyl), substituted alkyl, e.g. Aralkyl (e.g., benzyl, 2-phenylethyl) Hydroxyalkyl (eg 2-hydroxyethyl, 3-hydroxypropyl), Carboxyalkyl (e.g., 2-carboxyethyl, 3-carboxypropyl, 4-carboxybutyl, carboxymethyl), alkoxyalkyl (e.g. 2-methoxyethyl, 2- (2-methoxyethoxy) ethyl), sulfoalkyl (e.g. 2-sulfoethyl, 3-sulfopropyl, 3-sulfobutyl, 4-sulfobutyl, 2- (3-sulfopropyl) ethyl, 2-hydroxy-3-sulfopropyl, 3-sulfopropoxyethoxyethyl), sulfatoalkyl (e.g., 3-sulfatopropyl, 4-sulfatobutyl), heterocyclic substituted alkyl (e.g.  2- (pyrrolidin-2-one-1-yl) ethyl, tetrahydrofuryl, 2-morpholinethyl), 2-acetoxyethyl, carbomethoxymethyl, 2-methanesulfonylaminoethyl, allyl, aryl (eg phenyl, 2-naphthyl), substituted aryl (e.g., 4-carboxyphenyl, 4-sulfophenyl, 3-chlorophenyl, 3-methylphenyl) and heterocyclic groups (eg, 2-pyridyl, 2-thiazolyl).

Specific examples of the invention used Methine dyes and organic desensitizers Now given, but the invention should not be limited to these be limited.

Examples of compounds with the group represented by the general formula (II):

Examples of compounds with the group represented by the general formula (III):

Examples of compounds with the group represented by the general formula (IV):

Examples of compounds with the group represented by the general formula (V):

Examples of compounds with the group represented by the general formula (VI):

Examples of compounds with the group represented by the general formula (VII):

Examples of compounds with the group represented by the general formula (VIII):

Examples of compounds with the group represented by the general formula (IX):

The methine dyes used in this invention may be synthesized by following procedures according to JP-A-63-1 92 039 and US 48 14 265 applies.

Examples of specific organic desensitizers, represented by the general formula (X), will now be However, the present invention is not intended to be this be limited.

Examples of the synthesis of by the general formula (X) Compounds shown in JP-A-49-84 639 disclosed.

Specific examples of organic desensitizers, represented by the general formulas (XI) and (XII), will now be given, but the present invention is intended not limited to this.  

Synthesis Examples represented by the general formula (XI) Compounds shown are in J. Elguero, Comprehensive Heterocyclic Chemistry, Vol. 5, 4.04, pages 167-303, Pergamon Press (1984), and examples of synthesis by the general formula (XII) are shown in P.N. Preston, Heterocyclic Compounds Benzimidazoles and Congeneric Tricyclic Compounds, Vol. 40, Part 1, Chapter 1, Pages 1-285, John Wiley & Sons (1981).

When the methine dyes (preferably represented by formula (I), and more preferably by the general formula (VII) used in the present invention and those containing the groups represented by the formulas (II), (III), (IV), (V), (VI), (VIII) and (IX) are used as photographic desensitizing dyes or desensitizers, they are added to a photosensitive layer of a silver halide photographic material, generally at 5 × 10 ^-7 to 1 × 10 -4 ^{. 2} moles, preferably 5 × 10 ^-6 to 5 × 10 ^-3 moles, and more preferably 1 × 10 ^-4 to 1 × 10 ^-3 moles, per mole of silver halide The optimum amount depends on the chemical structure of the methine dye, Further, these methine dyes may be added during any stage of preparation of the silver halide photographic material, such as grain formation, physical or chemical ripening, and may have the excess of the crystal form and grain size of the silver halide photographic material solution may be added prior to application, or a combination of the aforementioned addition methods may be used.

The methine dyes used in the invention can directly in the photographic materials or hydrophilic  Colloid solution are dispersed. Furthermore, they can the photographic materials in the form of a solution in one suitable solvents are added, such as. B. Methyl alcohol, ethyl alcohol, propyl alcohol, methyl cellosolve, the halogenated ones mentioned in JP-A-9 715 and US-37 56 830 Alcohols, acetone, water, pyridine or in a mixture this solvent. By way of other methods of addition It is possible, for example, in JP-B-46-24 185, US 38 22 135, 36 60 101, 29 12 343, 29 96 287, 34 29 835 and 36 58 546 mentioned Apply method. Furthermore, it is also possible to in DE-OS 21 04 283 and US 36 49 286 mentioned method apply.

The organic desensitizers used in the present invention (preferably, the compounds represented by the general formulas (X), (XI) and (XII)) are preferably from 1 × 10 ^-6 mol to 5 × 10 ^-1 mol, more preferably 1 × 10 ^-5 mole to 2 × 10 ^-2 mole, per 1 mole of silver halide, and an amount within the range of 1 × 10 ^-4 mole to 1 × 10 ^-2 mole is particularly preferably added.

Including compounds of the formulas (X), (XI) and (XII) in photographic materials can this one Silver halide emulsion solution or a hydrophilic Colloid solution either as an aqueous solution, if water-soluble, or as alcoholic (eg, methanol, ethanol), Ester (e.g., ethyl acetate), ketone (e.g., acetone), or a Another solution in such a water-miscible organic Solvent, if insoluble in water, are added.

When added to the silver halide emulsion solution can be added at any desired time from the beginning  the chemical ripening carried out until application it is preferred, however, after the termination of the to carry out chemical ripening, and it is special preferred to add them to the coating solution used for Coating has been produced.

The silver halide emulsions used according to the invention can be through the acid, neutral or ammonia or a other such method are produced, wherein the Silver halides, e.g. B. silver bromide, silver chloride, Silver chlorobromide, silver iodobromide and silver iodochlorobromide lock in; Silver chlorobromide with a high Cl content is preferred when handling in a bright Safety light is considered important, and silver bromide or silver iodobromide are preferred when high photographic speed is considered important.

The average grain size of the invention used Silver halide grains may be 0.01 to 2 μm, but it is preferred to use grains of 0.02 to 1 micron. Further the grain size distribution can be wide or narrow, one However, narrow distribution is preferred. In particular, one is monodisperse emulsion preferred in the 90% and preferably 95% of the total number of grains within one Grain size range of ± 40% and preferably ± 20% the average grain size are. Furthermore, the Crystal form of the silver halide grains be monocrystalline, or several types of crystal forms may be mixed however, a single crystalline crystal form is preferred.

The direct-positive silver halides used according to the invention can the organic desensitizers or  Desensitizing dyes, either singly or in one Combination containing, which on the inorganic Desensitizers (in other words, for example, the Noble metal atoms contained in the silver halide grains are) and the silver halide surfaces are adsorbed.

When the inorganic desensitizers used in the present invention are incorporated in the silver halide grains, water-soluble noble metal compounds such as the salts of Group (VIII) metals of PSE such as iridium and rodium may be used as aqueous solutions during the preparation of the silver halide grains in an amount of 10 ^-7 to 10 ^{. 2} moles and preferably 10 ^-5 to 10 ^-3 moles per 1 mole of silver halide are added.

Other, usable according to the invention organic Desensitizers or desensitizing dyes close z. B. a: Dimethincyanin dyes with a 2- (nitro-substituted phenyl) indole nucleus, bis (1-alkyl-2-) phenyl) indole-3-trimethine cyanine dyes, Cyanine dyes with an aromatic substituted Indole nuclei, imidazoquinoxaline dyes, asymmetric Cyanine dyes with a carbazole nucleus, Trimethine cyanine dyes with a 2-aromatic-substituted Indolkernel, cyanine dyes with a 2,3,3-trialkyl-3H-nitroindole nucleus, cyanine dyes having a Pyrimidindionkern, quaternary merocyanine dyes with a 2-isooxazolin-5-one, 2-pyrazolin-5-one or Pyrimidinedione nucleus, cyanine dyes with a 2-allylimino (or alkylimino) -4-allyl (or alkyl 3-thiazoline nucleus, quaternary ammonium salts of merocyanine dyes a 2-allyl-amino or 3-lower alkanoic acid amide substituted  2-pyrazolin-5-onkernel, pyrilium, thiapyrilium, Selenium pyrilium salt dyes, cyanine dyes with a Nitro-substituted 2-arylindole nucleus, Bispyridinium salt dyes, cyanine dyes with a Pyrrole nucleus passing through the carbon atom in the 2-position 1,2-diaryltrimethinindole dyes, Cyanine dyes with a 4-pyrazole nucleus, Polymethine dyes with an imidazole nucleus, Dimethycyanine dyes with a 2-phenyl substituted Indole nuclei, trimethine cyanine dyes with two indole nuclei, Cyanine dyes with a 1-cyanoalkyl-2-arylindole nucleus, Cyanine and merocyanine dyes containing two nuclei have desensitizing substituents, such as nitro groups, Cyanine dyes with a 1-alkyl-2-phenyl-substituted Indolkernel, cyanine dyes with a 1-alkoxy-2-arylindolkern, cyanine dyes with a Imidato [4,5-b] quinoxaline nucleus containing cycloheptatriene Dyes containing indole nuclei Dimethycyanine dyes, cyanine dyes with a Pyrazolo [1,5-a] benzimidazole nucleus, cyanine dyes with a Pyrazole [5,1-b] quinazolone nucleus, dimethycyanine dyes with a pyrrole [2,3-b] pyridine core, cyanine dyes with a pyrrole nucleus, dyes with a Pyrrol [2,1-b] thiazole nucleus, cyanine dyes with a Indolenine or indole nucleus with phenylsulfonyl or Benzoyl-substituted groups based on compounds Nitrostyrene according to US 26 69 515, Pinacryptol Yellow, 5-meta-nitrobenzylidene-rhodanine and the bispyridinium compounds according to JP-B-48-13059 and the compounds based Phenazine according to JP-B-47-8,746.

The obfuscation of the invention used  direct positive silver halides can be replaced by a conventional Technique after removal of the water-soluble salts be carried out after the precipitation of the above Form silver halide. The obfuscation can help with a fogging agent (reducing agent) alone or in combination of the fogging agent and a Gold compound or an effective metal compound, the electrically more positive than silver.

Representative examples of such fogging agents that useful in the preparation of the emulsions z. Formalin, hydrazine, polyamines (e.g., triethylenetetramine, Tetraethylenepentamine), thiourea dioxides, Tetra (hydroxymethyl) phosphonium chloride, boramine, Borohydride compounds, stannous chloride, stannous chloride and the like, and representative examples of effective ones Metal compounds that are more electrically positive than silver are soluble salts of z. Gold, rhodium, palladium, Platinum and iridium, such as potassium chloroaurate, chloroauric acid, Palladium ammonium chloride, iridium sodium chloride and the like.

The fogging agents are used in a range of 1.0 × 10 ^-6 to 1.0 × 10 ^-1 mole per 1 mole of silver halide.

Chloroauric acid, sodium chloroaurate, gold sulfate, gold selenate, and the like may be cited as representative gold compounds, and it is generally preferable that they are included in a range of 1.0 × 10 ^-6 to 1.0 × 10 ^-4 mole per 1 mole of silver halide are.

The obfuscation level for the pre-obfuscated direct positive silver halide emulsions described in U.S. Pat The present invention is applied over a wide Variable range. As for the technician on this Area is well known, is the degree of obfuscation of type and concentration of the fogging agent, the pH, pAg, the temperature and duration of the emulsion during the obfuscation, as well as the Silver halide composition and grain size of Silver halide emulsion dependent.

It is possible to add a high photographic speed the direct positive silver halide photographic materials of the present invention, by at least a sensitizing dye or others Substances selected from selenium compounds according to JP-A-46-4282, and sensitizing dyes such as Dimethine or trimethine cyanine dyes, Halogen-substituted hydroxyphthalin dyes, Phenazine based dyes, cyanine dyes with a Benzothiazole or benzselenazole nucleus, cyanine dyes with a naphthoxazole core, dyes based on Triphenylmethane, cyanine dyes with an indolenine nucleus, Cyanine dyes with a 2-pyridine rhodane linker, Merocyanine dyes with a thiazole nucleus, asymmetric Cyanine, quinoline and meso-substituted cyanine dyes, Merocyanine dyes with a Rhodaninkern or Polymethine dyes with three nuclei.

It is possible to use various other, commonly used photographic additives in the direct positive  Silver halide photographic materials of the present invention To include invention. As stabilizers z. B. Triazoles, azaindenes, quaternary benzthiazolium compounds, Mercapto compounds or water-soluble inorganic Salts of cadmium, cobalt, nickel, manganese, gold, thallium, Zinc and the like are included. Furthermore, can as a film hardener z. Aldehydes or ants, Glyoxal and mucochloric acid, S-triazines, epoxides, aziridines, Vinylsulfonic acid and the like, and as Coating agent z. Saponin, sodium polyalkylene sulfonate, Lauryl or oleyl monoethers of polyethylene glycol, aluminized alkyl taurine, fluorine containing compounds and may be included. In addition, you can Color couplers are added. In addition, whiteners, Ultraviolet absorbers, preservatives, matting agents, Antistatic agents and the like are added as required become.

Furthermore, in the direct positive Silver Halide Photography Materials Filter Dyes be incorporated, which are dyes that absorbing and cutting out visible light, and indeed so that handling under a fluorescent lamp allows to use the ultraviolet light when using an ultraviolet light source.

The dyes used according to the invention have their Main absorption in the visible wavelength range of the relevant wavelength sensitivity range of used silver halide emulsions. In the chemical Structure of the dyes is not particularly limited and it is possible oxonol, hemioxonol, merocyanine,  To use cyanine, azo dyes and the like, however, water-soluble dyes are advantageous in that as they eliminate paint residue after preparation.

Specifically, it is possible, for. As the pyrazolone dyes according to JP-B-58-12576, the pyrazolone oxonal dyes according to US 22 74 782, the diarylazo dyes according to US 29 56 879, the styryl dyes and butadienyl dyes according to US 34 23 207 and 33 84 487, the Merocyanine dyes according to US 25 27 583, which Merocyanine and oxonol dyes according to US 34 86 897, 36 52,284 and 37,118,472, the enamine hemioxonol dyes according to US 39 76 661 and the dyes according to GB 5 84 609, 11 77 429, JP-A-48-85 130, JP-A-49-99 620, JP-A-49-1 14 420 and US 25 33 472, 31 48 187, 31 77 078, 32 47 127, 35 40 887, 35 75 704 and 36 53 905 to use.

Various surfactants can be incorporated into the photographic emulsion layers of the photographic Material or other hydrophilic colloid layers to be included using the present Invention be prepared for various purposes, such as as a coating aid, to prevent static Charges, to improve the sliding properties, Emulsification and dispersion, for the prevention of Bonding and improving the photographic Properties (such as development acceleration, hardening and Sensitization).

For example, it is possible to use saponin (based on steroid), Alkylene oxide derivatives (for example, polyethylene glycol, polyethylene glycol / polypropylene glycol Condensates, polyethylene glycol alkyl ethers  or polyethylene glycol alkylaryl ether, polyethylene glycol ester, Polyethylene glycol sorbitan esters, polyalkylene glycol alkylamines or amides, polyethylene oxide adducts of silicone), Glycidol derivatives (eg alkenyl succinate, polyglyceride, Alkylphenol polyglyceride), aliphatic polyhydric esters Alcohols, alkyl esters of sugars and other such nonionic surfactant; alkyl carbonates, Alkyl sulfonates, alkyl benzene sulfonates, Alkylnaphthalenesulfonates, alkyl sulfate esters, alkyl phosphate esters, N-acyl-N-alkyl-purines, sulfosuccinate esters, Sulfoalkylpolyoxyethylenalkylphenylester, Polyoxyethylalkylphosphatester and other such anionic surfactants with carboxyl, Sulfo, phospho, sulfate ester, phosphate ester or others such acidic groups; Amino acids, aminoalkyl sulfonates, Aminoalkyl sulfate or phosphate esters, alkyl betaines, amine oxides and other such amphoteric surfactants; Alkylamine salts, aliphatic or aromatic quaternary Ammonium salts, heterocyclic quaternary ammonium salts of Pyridinium, imidazolium and the like, and phosphonium or sulfonium salts with aliphatic or heterocyclic Rings and other such cationic surfactants Means to use.

Preferred surface active agents according to the invention the polyalkylene oxides with molecular weights of 600 or more according to JP-B-58-9 412.

The polyalkylene oxide compounds used in the invention close z. B. block polymers of two or more types of Polyalkylene oxides or condensates of compounds with at least one active hydrogen atom, such as water,  aliphatic alcohols, aromatic alcohols, aliphatic Acid, organic amine or hexitol derivatives, and Alkylene oxides having 2 to 4 carbon atoms, such as Ethylene oxide, propylene-1,2-oxide, butylene-1,2-oxide and preferably polyalkylene oxides with at least 10 units of ethylene oxide. In other words it is for example especially possible, the polyalkylene oxide to use:

polyalkylene
Polyalkylenalkylether,
Polyalkylenglykolarylether,
Polyalkylene glycol (alkylaryl) ether,
polyalkylene,
Polyalkylene glycol-aliphatic acid amides,
polyalkylene glycol amines,
Polyalkylene glycol block copolymers, or
Polyalkylene glycol graft.

It is necessary that the molecular weights be 600 or more be.

The polyalkylene oxides are not one within the Restricted molecule, and two or more be included. In this case, the individual Polyalkylene oxide less than 10 alkylene oxide units but the entirety of the alkylene oxide units within the molecule must be at least 10. If two or more polyalkylene oxides within the molecule These can consist of two different ones Alkylene oxide units exist, such as ethylene oxide and Propylene oxide. The inventively used  Polyalkylene oxide compounds preferably contain from 14 to 100 alkylene oxide units.

Specific examples of the invention used Polyalkylene oxide compounds are as follows, the present invention However, the invention should not be limited to these.

It can the polyalkylene oxide according to JP-A-50-1 56 423, JP-A-52-1 08 130 and JP-A-53-3 217, and e.g. B. the following examples of the polyalkylene oxide compounds be used:

These polyalkylene oxide compounds may be used alone or in Combination of two or more types are used.

When these polyalkylene oxide compounds the Silver halide emulsions are added, it is possible this the emulsion at an appropriate time before the To coat, preferably after the chemical Ripening, either suitable as aqueous solutions Concentration or by dissolving in water miscible, low boiling, organic solvents. You can also use a light-insensitive hydrophilic Colloid layer are added, such as an intermediate layer, Protective layer, filter layer or the like, without the Emulsion to be added.

Silica, magnesium oxide, poly (methyl methacrylate) and others such matting agents can be used in the photographic Emulsion layers or other hydrophilic Colloid layers in the photographic materials according to the invention be included to prevent sticking.

Dispersions of synthetic polymers in water insoluble or slightly soluble in the photographic emulsions of the invention for the purpose to improve the dimensional stability. For example, it is possible to use alkyl (meth) acrylate, Alkoxyalkyl (meth) acrylate, (meth) acrylamide, vinyl esters (eg. Vinyl acetate), acrylonitrile and the like, either individually or in combination.

In the emulsions used in the invention is Gelatin is mainly used as the protective colloid, and  it is particularly advantageous to use inert gelatin. In addition to gelatin, it is possible to photographically inert Gelatin derivatives (eg gelatin phthalate) and water-soluble synthetic polymers (eg polyvinyl acrylate, Polyvinyl alcohol, polyvinylpyrrolidone). With The novel emulsions of the present invention may be any desired, suitable photographic base used be, for. Glass, film underlays, such as cellulose acetate, Cellulose acetate butyrate or polyester (e.g. Polyethylene terephthalate).

Developers can use development solutions which are a low sulfite concentration and it is possible to develop solutions too use the appropriate amounts of sulphite ions (in particular 0.15 mol / l or more) as condoms contain, and the pH of the developing solutions can 9.5 or above, especially 10.5 to 12.3.

There are no special restrictions on the Development agents, and it may, for. B. dihydroxybenzenes (eg hydroquinone), 3-pyrazolidones (e.g. 1-phenyl-3-pyrazolidone, 4,4-dimethyl-1-phenyl-3-pyrazolidone), Aminophenols (eg N-methyl-p-aminophenol), either individually or in combination.

In addition, in the development solutions pH buffers, such as the sulfites, carbonates, borates and phosphates of Alkali metals, development inhibitors and Anti-fogging agents, such as boron compounds, iodine compounds and organic anti-foggants (nitroindazoles and benzotriazoles are particularly preferred)  become. Furthermore, water softeners, solution aids, Color toner, development accelerator, surface-active Mean (the above-mentioned polyalkylene oxides particularly preferred), defoamers, film hardeners, compositions for Prevention of film stains (eg 2-mercaptobenzimidazole sulfonates) and the like be as required. specific Examples of these additives are, for. In Research Disclosure, Nos. 176, 17643 called.

Processing temperatures are between 18 and 50 ° C normally chosen, but it is possible temperatures below 18 ° C or above 50 ° C.

It may conventional compositions for the fixator solution be used.

In addition to thiosulfates and thiocyanates, organic Sulfur compounds of known activity as fixators be used. Furthermore, water-soluble aluminum salts be included in the fixer solution as a film hardener.

The direct positive according to the invention Silver halide photographic materials are becoming various Applications used. Examples of their use are various photography materials for printing, such as Duplicate, Reproduction and Off-set Masters, as Special photography materials for X-ray photography, Flash photography, electron beam photography and the like or as different direct positive Photographic materials for general repro photography, Micro reprography, direct positive color usages, fast  Stabilization Uses, Diffusion Transfer Uses, Color diffusion transfer uses and combined Development and fixation uses.

Generally, in the case of direct positive silver halide emulsions, the silver halide grain surfaces are pre-fogged using a fogging agent and bleached with the positive holes produced by exposure of the fogged nuclei, and direct positive images are obtained by treating them with a developing solution and developing the unexposed portions without exposing to develop exposed parts. In the present invention, it has been found that the spectral sensitizing effect of methine dyes in direct-positive silver halide emulsions becomes highly color-sensitized by the addition of organic desensitizers, and thereby not only high spectral sensitivity is obtained, but also changes in photographic speed and minimum density ( D _min ) during storage of the raw materials without increasing the minimum density ( D _min ) of the exposed parts.

The invention will now be described in more detail with reference to FIGS particular examples, but the invention is intended not limited to this.

Unless otherwise indicated, all parts refer to Percentages and ratios by weight.

example 1

A monodispersed silver chlorobromide emulsion having an average grain size of 0.2 μm was prepared by simultaneously adding at a fixed rate over 30 minutes an aqueous silver sulfate solution and a mixed aqueous solution of sodium chloride and potassium bromide to an aqueous gelatin solution at 50 ° C with 1 x 10 ^-5 Mol per 1 mol of silver in the presence of rhodium chloride (Cl content 90 mol .-%) admitted.

The desalting of the emulsion was carried out using the Flocculation method carried out, there were 2 mg Thiourea dioxide and 0.9 mg of potassium chloroaurate per 1 mole Silver added, the ripening performed until the Maximum reached at 65 ° C, and veiled.

These emulsions were divided, and as shown in Table 1 below, the emulsions were prepared by using methine dyes and organic desensitizers according to the invention and then 4 × 10 ^-4 moles of the polyalkylene oxide compound (XIII-7) per 1 mole of silver 10% aqueous KBr solution and added as film hardener sodium 2-hydroxy-4,6-dichloro-1,3,5-triazine and 1,3-divinylsulfonyl-2-propanol. Silica and ethyl acrylate dispersions were added as a matting agent and applied to a polyethylene terephthalate film having a silver amount of 3.0 mg / m 2 with simultaneous application of a gelatin protective layer containing sodium dodecylbenzenesulfonate as a surface active agent. The obtained samples were exposed through an optical wedge using a tungsten light source and then developed for 20 seconds at 38 ° C in a developing solution having the following composition. The results after breakage, fixation, washing and drying are shown in Table 2 as the photographic properties 1.

For the photographic properties 2 became the same Reviews as for the photographic properties 1 made, after 3 days leaving a every film under the conditions of 50 ° C and 75% relative humidity.

The relative speed here is the reciprocal Relative value for an exposure that has a density of 1.5 at a development of 20 seconds at 38 ° C, being the relative speeds of the materials Nos 2, 3 and 4 based on the value of photographic properties 1 of Example 1 as 100 were determined. In the same way the Relative speeds of materials no. 5, 9, 13, 17, 21, 25, 29, 33, 37, 41, 45, 49, and 53, respectively the values of the photographic properties 1 as 100 certainly. Further, the following developer solution for the development uses:

Developer solution: Hydroquinone | 35.0 g N-methyl-p-aminophenol 1/2 sulfuric acid salt 0.8 g sodium hydroxide 9.0 g potassium triphosphate 74.0 g potassium 90.0 g Natriummethylendiamintetraacetat 1.0 g 3-dimethyl-amino-1-propanol 15.0 g 5-methylbenzotriazole 0.5 g sodium 3.0 g Water up 1 l pH adjusted to 11,60

Comparative Dye A

Table 1

Continuation Table 1

Table 2

Continuation Table 2

Tables 1 and 2 show that the common use the methine dye and the organic desensitizer high sensitivity according to the present invention and provides improved storage stability.

Example 2

An aqueous gelatin solution containing 0.8 g / l of sodium bromide was kept at 70 ° C and a monodispersed emulsion of cubic silver bromide having an average grain size of 0.25 μm was prepared by simultaneously stirring at a fixed speed over 85 minutes aqueous silver nitrate solution and an aqueous potassium bromide solution in the presence of 5 × 10 ^-6 mol / mol Ag rhodium salt and 5 × 10 ^-7 mol / mol Ag iridium salt and the potential at +60 mV over this period. This emulsion was desalted using the flocculation method, 10 mg of thiourea dioxide and 8 mg of potassium chloroaurate per 1 mol of silver were added, the ripening was carried out until the maximum was reached at 65 ° C, and fogged.

These emulsions were divided and, as shown in the following Table 3, according to the invention, the methine dyes and organic desensitizers were added. Compound (14) according to JP-A-49-29 828 was added at 6 × 10 ^-4 mol per mol of silver and the pAg was adjusted at 8 x 10 ^-4 mol of polyoxyalkylene oxide compound (XIII-7) and 10% KBr per 1 mol of silver , 1,3-divinylsulfonyl-2-propanol was added as a film hardener, and then silicate and a gelatin-containing protective layer to which sodium dodecylbenzenesulfonate surfactant was added were simultaneously applied to a polyethylene terephthalate film having a silver amount of 3.2 g / m 2.

A backing layer and a backing layer were applied to the applied opposite side, forming a Sandwich of backing, protective layer and emulsion layers. The back layer contained potassium 4- [5-oxo-3-methyl-4 (4-N, N- dimethylaminophenyl) methylene-2-pyrazolinyl] benzenesulfonate and potassium 4- [3-carboxy-5-hydroxy-4 {5- (3-carboxy-5-oxo-1) (4-sulfophenyl) -2-pyrazolin-4-irises} -1,3-pentadienyl) -1-pyrazolyl] -1- Benzenesulfonate as dyes and contained a Ethyl acrylate polymer to improve the film properties. Surface active agents, static modifiers and Film hardeners were applied together with the gelatin. In the reverse protection layer became a polymethyl methacrylate polymer the gelatin as a surfactant and Added matting agent, and this was applied to the backing layer (the opposite side of the pad) applied.

The resulting materials were passed through an optical wedge exposed using a tungsten light source and the same reviews as in Example 1 performed. The Results are shown in Table 4. Furthermore, the Relative speeds of materials no. 57, 61, 65, 69, 73, 77, 81, 85, 89, 93, 97, 101 and 105 based on the values of photographic properties 1 as 100 in the same manner as in Example 1.  

Table 3

Continuation Table 3

Table 4

Continuation Table 4

Tables 3 and 4 show that the joint use of the Methine dye and the organic desensitizer according to the present invention high sensitivity and improved storage stability.

By the invention in detail and with reference to the specific examples has been described, it is for the average expert obvious that different Amendments and modifications can be made without departing from the spirit and scope of the invention.

Claims (19)

A direct-positive silver halide emulsion containing a photosensitive silver halide, a binder, at least one methine dye having a heterocyclic azulene group containing as a heteroatom at least one nitrogen atom or chalcogen atom, said 7-membered ring contained in said heterocyclic azulene group having a color-forming conjugated resonance unit with the one 10 forms an π electron system of the azulene, and wherein said methine dye is substituted on the methine bond with an auxochromic group, and an organic desensitizing compound having a reduction potential equal to or more positive than -1.0 V _vs SCE. A direct positive silver halide emulsion according to claim 1, characterized in that said heterocyclic azulene group is represented by the general formula (I) or a resonance form thereof: wherein V₁, V₂, V₃, V₄, V₅ and V₆, which may be the same or different, are each hydrogen, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted acyl, substituted or unsubstituted acyloxy, substituted or unsubstituted alkoxycarbonyl, substituted or unsubstituted carbamoyl, substituted or unsubstituted sulfamoyl, substituted or unsubstituted carboxyl, cyano, hydroxyl, substituted or unsubstituted amino, substituted or unsubstituted acylamino, substituted or unsubstituted alkoxy, substituted or unsubstituted alkylthio, substituted or unsubstituted alkylsulfonyl, sulfonic acid or substituted or unsubstituted aryl, provided that at least one V₂ to V₆ represents a group formed by a methine carbon group L connecting said heterocyclic azulene group with said auxochromic group E, and da each of Y and Z₂, which may be identical or different may be joined by two V₂ to V₆, which are attached to adjacent carbon atoms to form a fused ring, respectively wherein V has the same meaning as V₁, a chalcogen or in which R₃ represents hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, a heterocyclic group or a salt thereof, provided that at least one of Y and Z₂ represents a group other than a carbon atom, wherein when Y and Z₂ each represents a chalcogen atom or Nitrogen, at least one Y and Z₂ represents nitrogen, and when one Y and Z₂ represents a chalcogen and the other represents carbon or nitrogen, Z₂ represents chalcogen and Y represents carbon or nitrogen, wherein M represents a counterion required for charge balance and m is 0 or a whole Number is necessary to charge balance. A direct positive silver halide emulsion according to claim 2, characterized in that the group formed by L and E is represented by the formula: wherein Q₁ represents an atomic group necessary for forming a 5- or 6-membered nitrogen-containing ring, L₁, L₂, L₃, L₄ and L₅ each represent a substituted or unsubstituted methine group, R₄ is a substituted or unsubstituted alkyl group, l ₁ 0 or an integer Number of 1 to 3 and n ₁ 0 or 1 are. A direct positive silver halide emulsion according to claim 2, characterized in that the group formed by L and E is represented by the formula (III): wherein Q₂ L₆, L₇, L₈, L₉ and L₁₀ represents an atomic group necessary for forming a 5- or 6-membered nitrogen-containing ring, a substituted or unsubstituted methine group, R₅ is a substituted or unsubstituted alkyl group, l ₂ 0 or an integer Number of 1 to 3 and n ₂ 0 or 1 are. A direct positive silver halide emulsion according to claim 2, characterized in that the group formed by L and E is represented by the formula (IV): wherein Y 'the same definition as Y, Z₂' the same definition as Z₁, V₁ ', V₂', V₃ ', V₄' and V₅ 'each have the same definition as V₁, L₁₁, L₁₂ and L₁₃ each represents a substituted or unsubstituted methine group and l ₃ is 0 or an integer from 1 to 3. A direct positive silver halide emulsion according to claim 2, characterized in that the group formed by L and E is represented by the formula (V): wherein D₁ and D₁, respectively 'each represent a cyclic or acyclic atomic group necessary for forming an acidic nucleus, L₁₄, L₁₅, L₁₆ and L₁₇ a substituted or unsubstituted methine group, l ₀ or an integer of 1 to 3 and n ₃ 0 or 1. 7. Direct positive silver halide emulsion according to claim 2, characterized in that the group formed by L and E is represented by the formula (VI): wherein R₆ and R₇ are each a substituent, L₁₈ and L₁₉ each represents a substituted or unsubstituted methine group, and l ₅ 0 or an integer of 1 to 3. A direct positive silver halide emulsion according to claim 2, characterized in that said sensitizing agent is represented by the formula (VII): wherein at least one E and E 'are E₁ and the other E₁ or E₂, V₁, V₂, V₃, V₄, V₅ and V₆, which may be the same or different, are each hydrogen, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted acyl, substituted or unsubstituted acyloxy, substituted or unsubstituted alkoxycarbonyl, substituted or unsubstituted carbamoyl, substituted or unsubstituted sulfamoyl, substituted or unsubstituted carboxyl, cyano, hydroxyl, substituted or unsubstituted amino, substituted or unsubstituted acylamino, substituted or unsubstituted alkoxy, substituted or unsubstituted alkylthio, substituted or unsubstituted alkylsulfonyl, sulfonic acid or substituted or unsubstituted aryl, provided that at least one V₂ to V₆ represents said bond to L₂₀ or L₂₄, and that each of two V₂ to V₆ adjacent to arte carbon atoms are bonded, may be connected to form a fused ring, Y and Z₂, which may be the same or different, respectively wherein V has the same meaning as V₁, a chalcogen or wherein R₃ is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted aral, heterocyclic group or salt thereof, provided that at least one of Y and Z₂ represents a group other than a carbon atom, wherein when Y and Z₂ each represents a chalcogen atom or nitrogen, at least one Y and Z₂ are nitrogen, and when one Y and Z₂ is a chalcogen and the other is carbon or nitrogen, Z₂ is chalcogen and Y is carbon or nitrogen, where M is a counterion required for charge balance, and m is 0 or one is an integer necessary for charge balance, and wherein W₁ represents an atomic group necessary for forming a 5- or 6-membered heterocyclic ring, R₈ is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl or a heterocyclic group, Q₃ an atomic group leading to formation a 5- or 6-membered nitrogen-containing ring is necessary, R₉ represents substituted or unsubstituted alkyl, L₂₀, L₂₁, L₂₂, L₂₃, L₂₄, L₂₅ and L₂₆ are each a substituted or unsubstituted methine group, l ₆ and l ₇ each 0 or an integer from 1 to 3 and n ₄ are 0 or 1. 9. A silver halide emulsion according to claim 2, characterized in that the group formed by L and E is represented by formula (VIII): where W₂ is an atomic group necessary to form a 5- or 6-membered heterocyclic ring, R₁₀ is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or a heterocyclic group, D₂ and D₂ 'are each an acyclic or cyclic atomic group Formation of an acidic nucleus is necessary, L₂₇, L₂₈, L₂₉, L₃₀, L₃₁ and L₃₂ each represents a substituted or unsubstituted methine group, l ₈ and l ₉ are each 0 or an integer from 1 to 3 and n ₅ 0 or 1. A direct positive silver halide emulsion according to claim 3, characterized in that the group formed by L and E is represented by the formulas (IX) a or (IXb): wherein L₃₃ and L₃₄ are each a substituted or unsubstituted methine group, Ar is an aromatic group and l ₁₀ 0 or an integer of 1 to 3. 11. Direct positive silver halide emulsion according to claim 2, characterized in that R₃ an unsubstituted alkyl group or a Sulfoalkyl group, V₂, V₃, V₄ and V₅ in each case Hydrogen, V₁ is hydrogen, chlorine, an alkoxy group, an alkylthio group or an aryl group, and V₆ die represent said group formed by L and E. A direct positive silver halide emulsion according to claim 1, characterized in that said organic desensitizer is represented by the formula (X): wherein Z₁ is an atomic group necessary to form a nitrogen-containing heterocyclic ring, T₁ is halogen, alkyl, acyl, acyloxy, acylamino, alkoxy, alkoxycarbonyl, carbamoyl, sulfamoyl, carboxyl, cyano, hydroxyl, amino, alkylthio, alkylsulfonyl, sulfonic acid, sulfonamide, Aryl or a fused ring, q is 1, 2 or 3, and r ₁ is 0, 1, 2 or 3. A direct positive silver halide emulsion according to claim 1, characterized in that the organic desensitizer is represented by the formula (XI): wherein R₁ is hydrogen, alkyl, aryl or a heterocyclic group, T₂ halogen, alkyl, acyl, acyloxy, acylamino, alkoxy, alkoxycarbonyl, carbamoyl, sulfamoyl, carboxyl, cyano, hydroxyl, amino, alkylthio, alkylsulfonyl, sulfonic acid, sulfonamide, aryl or a fused ring, q ₂ 1, 2 or 3 and r ₂ 0, 1, 2 or 3 are. 14. A direct positive silver halide emulsion according to claim 1, characterized in that said organic desensitizer is represented by the formula (XII): wherein R₂ is hydrogen, alkyl, aryl or a heterocyclic group, T₃ halogen, alkyl, acyl, acyloxy, acylamino, alkoxy, alkoxycarbonyl, carbamoyl, sulfamoyl, carboxyl, cyano, hydroxyl, amino, alkylthio, alkylsulfonyl, sulfonic acid, sulfonamide, aryl or a fused ring, q ₃ 1, 2 or 3 and r ₃ 0, 1, 2 or 3 are. A direct positive silver halide emulsion according to claim 1, which contains 5 x 10 ^-7 to 1 x 10 ^-2 mol of methine dye and 1 x 10 ^-6 to 5 x 10 ^-1 mol of organic desensitizer per mol of silver halide. 16. Direct positive silver halide emulsion according to claim 15, characterized in that it contains 5 × 10 ^-6 to 5 × 10 ^-3 mole of methine dye and 1 × 10 ^-5 to 2 × 10 ^-2 mole of organic desensitizer per mole of silver halide. A direct positive silver halide emulsion according to claim 15, characterized in that the silver halide comprises grains containing from 10 ^-7 to 10 ^-2 moles of rhodium per mole of silver halide. 18. A silver halide emulsion photographic material comprising a support and thereon at least one photosensitive, direct positive silver halide emulsion containing a photosensitive silver halide, a binder, at least one methine dye having a heterocyclic azulene group containing as heteroatom at least one nitrogen atom or chalcogen atom, the azulene contained in the azulene 7-membered ring forms a color-forming conjugated resonance unit with the 10 π electron system of the Azulens, and wherein the methine dye is substituted on the methine bond with an auxochromic group, and at least one organic Desensibilisierungsverbindung with a reduction potential equal to or more positive than -1 , 0 V _vs SCE is. 19. A photosensitive material according to claim 18, characterized characterized in that said photosensitive emulsion layer or one on it adjacent layer of a polyalkylene oxide with a Molecular weight of at least 600 included.