GB2176304A - Silver halide photographic emulsion - Google Patents

Abstract

A silver halide photographic emulsion is described, containing a nitrogen-containing heterocyclic compound represented by the following general formula (I) and a cyanine dye as a combination thereof <IMAGE> wherein R<1> represents an aliphatic group, an aromatic group or a heterocyclic group; each of said groups being substituted by at least one -COOM or SO3M (wherein M represents a hydrogen atom, an alkali metal atom, a quaternary ammonium or a quaternary phosphonium).

Description

SPECIFICATION Silver halide photographic emulsions This invention relates to a spectrally sensitized silver halide photographic emulsion. More particularly, the invention relates to a supersensitized silver halide photographic emulsion containing cyanine dye(s).

In the production technique for silver halide photographic emulsions, it has been desired to further increase the sensitivity of the photographic emulsions. As a useful method for increasing the sensitivity of a silver halide photographic emulsion, a chemical sensitization method and a spectral sensitization method are known.

The spectral sensitization is a technique of increasing the sensitivity of a photographic emulsion by incorporating sensitizing dye(s) in a silver halide photographic emulsion to expand the sensitive wavelength region of the silver halide photographic emulsion, which is limited to a short wavelength region of visible light, to a long wavelength region of visible light. As the sensitizing dyes, cyanine dyes, etc., are mainly used and many sensitizing dyes and the application methods thereof are known.In particular, a method of obtaining a higher sensitizing effect, by using a combination of two or more kinds of sensitizing dyes or a combination of a sensitizing dye and a compound which does not have spectral sensitizing property by itself or has a very poor spectral sensitivity, than the spectral sensitization obtained by the use of each sensitizing dye only is known and is called "supersensitization".

The term "supersensitization" in this specification is understood to include not only the effect that the spectral sensitizing ratio (that is, the ratio of sensitivity in spectral sensitivity region/sensitivity in intrinsic sensitivity region) becomes higher than the case of using each dye individually but also the effect that the sensitivity in a spectral sensitizing region is increased as a result of the effect of increasing the sensitivity in the intrinsic sensitivity region by a combination of a sensitizing dye and other compound over the case of using each dye or compound individually.

It is well known that a heterocyclic compound having a mercapto group is useful as an antifoggant for photographic emulsions but, on the other hand, it is also known that such a compound reduces the sensitivity of photographic emulsions. These matters are described, for example, in C.E.K. Mees and T.H. James, The Theory of the Photographic Process, 3rd Edition, pages 344-346 (1967).

It is known in Japanese Patent Application (OPI) No. 64419/74 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application") that the spectral sensitizing action of a cyanine dye having a pyridine nucleus at at least one of the two heterocyclic ring nuclei, that is, a pyridinocyanine dye (or pyridocyanine dye), is increased by using the dye as a combination thereof with a certain kind of mercapto compound having an acid group. However, the invention of the above-described patent application is applied only to a monomethinecyanine dye or a trimethinecyanine dye having a pyridine nucleus but is not applied to cyanine dyes having other structures. Furthermore, the sensitizing dyes in the aforesaid invention are greatly low in the color sensitizing efficiency as in the case of sole use as compared with other cyanine dyes.Also, it is known in Japanese Patent Application (OPI) No. 77224/76 that a heterocyclic mercapto compound having no acid group gives a supersensitizing action for the spectral sensitization of trimethinecyanine dyes in wide range other than pyridinocyanine dyes.

However, the above-described method has the disadvantage that with the application of the mercapto compound, desensitization by inhibiting development occurs to reduce the sensitization effect obtained by supersensitization, whereby the effect cannot be sufficiently obtained.

British Patent 1,275,701 discloses the use of a cyanine dye together with a compound represented by the following general formula (A) as an antifoggant capable of stabilizing silver halide emulsions without reducing the sensitivity thereof

wherein R and R' each represents a hydrogen atom, an alkali metal atom, or a quaternary ammonium salt.

However, in the above-described British Patent, there is only a general description about the silver halide emulsions and the patent does not refer to any specific composition of silver halide emulsions.

On the other hand, the inventors have discovered that the halogen composition and the structure of the silver halide emulsion are very important for obtaining the effect of this invention.

An object of this invention is to provide a silver halide photographic emulsion spectrally sensitized by new supersensitizing means.

Another object of this invention is to provide a silver halide photographic emulsion highly spectrally sensitized and giving inhibited occurrence of fog.

Still another object of this invention is to provide a photographic light-sensitive material using the above-described silver halide photographic emulsion.

As a result of investigations for eliminating the disadvantage that the supersensitizing effect is reduced by the effect of development inhibition, the inventors have discovered that the abovedescribed objects can be attained by a silver halide photographic emulsion containing a nitrogencontaining heterocyclic compound represented by the following general formula (I) and a cyanine dye as a combination thereof:

wherein R' represents an aliphatic group, an aromatic group or a heterocyclic group, each group being substituted by at least one -COOM OR -SO3M and M represents a hydrogen atom, an alkali metal atom, a quaternary ammonium or a quaternary phosphonium.

DETAILED DESCRIPTION OF THE INVENTION In this invention, the compounds represented by the general formula (II) described hereinafter are particularly preferred as the above-described nitrogen-containing heterocyclic compound.

Also, in this invention, the supersensitization effect by the use of a cyanine dye and the nitrogen-containing heterocyclic compound is influenced by the halogen composition and the structure of silver halide, and from the viewpoint, silver iodochlorobromide or silver iodobromide is preferred. In this case, the effect is large when the content of silver iodide is less than 12 mol%, preferably 12 to 1 mol%, particularly preferably 10 to 2 mol%. Also, in regard to the halogen distribution of the silver halide, it may have a uniform composition or may have different compositions between the inside and the outside thereof. Also, the silver halide grains having a layer structure may be used.However, the silver halide grains having a structure of substantially two clear layers composed of a core portion having high iodide content and a shell portion of low iodide content (a core/shell structure) are particularly preferred.

Then, the nitrogen-containing heterocyclic compounds represented by the general formula (I) shown above are explained in detail.

The aliphatic group shown by R' in the general formula (I) specifically includes a straight chain or branched alkyl group having 1 to 20 carbon atoms (e.g., a methyl group, a propyl group, a hexyl group, a dodecyl group, an isopropyl group, etc.) and a cycloalkyl group having 1 to 20 carbon atoms (e.g., a cyclopropyl group, a cyclohexyl group, etc.). The aromatic group shown by R1 specifically includes an aryl group having 6 to 20 carbon atoms (e.g., a phenyl group, a naphthyl group, etc.). Also, the heterocyclic group shown by R' specifically includes a 5membered, 6-membered or 7-membered heterocyclic ring containing at least one nitrogen, oxygen or sulfur atom, which may form a condensed ring at a proper position (e.g., a pyridine ring, a quinoiine ring, a pyrimidine ring, an isoquinoline ring, etc.).

Also, the above-described straight chain or branched alkyl group, the cycloalkyl group, the aryl group and the heterocyclic group each may further have substituent(s) in addition to -COOM or -SO3M. Specific examples of the substituent are a halogen atom (e.g., fluorine, chlorine, bromine, etc.), an alkyl group (e.g., a methyl group, an ethyl group, etc.), an aryl group (e.g., a phenyl group, a p-chlorophenyl group, etc.), an alkoxy group (e.g., a methoxy group, a methoxyethoxy group, etc.), an aryloxy group (e.g., a phenoxy group, etc.), a sulfonyl group (e.g., a methanesulfonyl group, a p-toluenesulfonyl group, etc.), a sulfonamido group (e.g., a methanesulfonamido group, a benzenesulfonamido group, etc.), a sulfamoyl group (e.g., a diethylsulfamoyl group, an unsubstituted sulfamoyl group, etc.), a carbamoyl group (e.g., an unsubstituted carbamoyl group, a diethylcarbamoyl group, etc.), an amido group (e.g., an acetamido group, a benzamido group, etc.), a ureido group (e.g., a methylureido group, a phenylureido group, etc.), an alkoxycarbonylamino group (e.g., a methoxycarbonylamino group, etc.), an aryloxycarbonylam no group (e.g., a phenoxycarbonylamino group, etc.), an alkoxycarbonyl group (e.g., a methoxycarbonyl group, etc.), an aryloxycarbonyl group (e.g., a phenoxycarbonyl group, etc.), a cyano group, a hydroxy group, a carboxy group, a sulfo group, a nitro group, an amino group (an unsubstituted amino group, a dimethylamino group, etc.), an alkylsulfinyl group (e.g., a methoxysulfinyl group, etc.), an arylsulfinyl group (e.g., a phenylsulfinyl group, etc.), an alkylthio group (e.g., a methylthio group), and an arylthio group (e.g., a phenylthio group, etc.).

The above-described group shown by R' may have two or more these substituents and in this case the substituents may be the same or different.

Particularly preferred compounds in the nitrogen-containing heterocyclic compounds represented by the general formula (I) described above (i.e., mercaptotetrazole derivatives) are those represented by the general formula (II)

wherein R2 represents a phenyl group substituted by at least one -COOM or -SO3M and the phenyl group may be further substituted by other substituent(s) in addition to -COOM or -SO3M.

As such other substituents, there are the substituents for the straight chain or branched alkyl group, the cycloalkyl group, the aryl group, and the heterocyclic group shown by R1 described above.

When the above-described phenyl group is substituted by two or more groups shown by -COOM or -SO3M, these groups may be the same or different. M in the general formula (II) is the same as defined in the general formula (I).

Then, specific examples of the preferred compounds represented by the general formula (I) above are illustrated below, but the compounds for use in this invention are not limited thereto.

The compound shown by the general formula (I) described above can be easily produced by using a reaction of an isothiocyanate and sodium azide as described, for example, in U.S. Patent 3,266,897, Japanese Patent Publication No. 21842/67, Japanese Patent Application (OPI) No.

111846/81, British Patent 1,275,701, D.A. Berges et al., Journal of Heterocyclic Chemistry, Vol. 15, page 981 (1978), R.G. Dubenko and V.D. Panchenko, Khimmia Geterotsklicheskikh Soedinenil, 1st Edition, pages 199 to 201 (1967) (Azole oder Jhaschie Geterotsikly), etc.

The compound can be added to a silver halide emulsion according to an ordinary addition method of additives for photographic emulsions. For example, the compound can be added to a photographic emulsion as a solution thereof in methanol, ethanol, methyl cellosolve, acetone, water, or a mixed solvent thereof.

Also, the compound shown by the general formula (I) may exist in any step for producing a photographic emulsion or may be added to a photographic emulsion in any step after the production thereof directly before coating. For example, the compound may be added to a photographic emulsion in a step of forming silver halide grains, a step of physical ripening or a step of chemical ripening.

As the cyanine dyes for use in this invention, the dyes represented by the following general formula (Ill) are preferred.

wherein Z1 and ZZ each represents an atomic group necessary for forming a 5-membered or 6membered heterocyclic ring, which may be condensed; R3 and R4, which may be the same or different, each represents an alkyl group which may be substituted; L1, L2 and b, which may be the same or different, each represents a methine group which may be substituted; Xle represents an acid anion; k represents 1 or 2; and m represents an integer of 1 to 4; vyhen k is 1,.

the above-described dye forms an intramolecular salt.

Then, the dyes shown by the general formula (III) are explained below in detail.

In the general formula (III), Z1 and Zz represent an atomic group necessary for forming a 5membered or 6-membered heterocyclic ring, which may be condensed, as described above and they may be the same or different. Examples of the heterocyclic ring which may be condensed are a thiazole nucleus (e.g., thiazole, 4-methylthiazole, 4-phenylthiazole, 4,5-dimethylthiazole, 4,5diphenylthiazole, etc.), a benzothiazole nucleus (e.g., benzothiazole, 4-chlorobenzothiazole, 5chlorobenzothiazole, 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-hydroxy-6-methylbenzothiazole, tetrahydrobenzothiazole, 4-phenylbenzothiazole, etc.), a naphthothiazole nucleus (e.g., naphtho [ 2,1-d ] thiazole, naphtho [ 1 ,2-d ] thiazole, naphtho [ 2,3- ] thiazole, 5-methoxynaphtho [ 1,2- d ] thiazole, 7-ethoxynaphtho [ 2, 1 -d ] thiazole, 8-methoxynaphtho [ 2, l-d ] thiazole, 5-methoxynaphtho [ 2,3-d ] thiazole, etc.), a thiazoline nucleus (e.g., thiazoline, 4-methylthiazoline, 4-nitrothiazoline, etc.), an oxazole nucleus (e.g., oxazole, 4-methyloxazole, 4-nitroxazole, 5-methyloxazole, 4phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole, etc.), a benzoxazole nucleus (e.g., benzoxazole, 5-chlorobenzoxazole, 5-methylbenzoxazole; 5-bromobenzoxazole, 5-fluorobenzoxazole, 5phenylbenzoxazole, 5-methoxybenzoxazole, 5-nitrobenzoxazole, 5-trifluoromethylbenzoxazole, 5hydroxybenzoxazole, 5-carboxybenzoxazole, 6-methylbenzoxazole, 6-chlorobenzoxazole, 6-nitrobenzoxazole, 6-methoxybenzoxazole, 6-hydroxybenzoxazole, 5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, 5-ethoxybenzoxazole, etc.), a napthoxazole nucleus (e.g., naphtho [ 2, 1 -doxazole, naphtho 1 ,2-d ] oxazole, naphtho [ 2,3-d ] oxazole, 5-nitronaphtho [ 2, l-d ] oxazole, etc.), an oxazoline nucleus (e.g., 4,4-dimethyloxazoline, etc.), an isoxazole nucleus (e.g., 5-methylisoxazole, benzisoxazole, etc.), a selenazole nucleus (e.g., 4-methylselenazole, 4-nitroselenazole, 4-phenylselenazole, etc.), a benzoselenazole nucleus (e.g., benzoselenazole, 5-chlorobenzoselenazole, 5-nitrobenzoselenazole, 5-methoxybenzoselenazole, 5-hydroxybenzoselenazole, 6-nitrobenzoselenazole, 5chloro-6-nitrobenzoselenazole, etc.), a naphthoselenazole nucleus (e.g., naphtho [ 2, 1 -d ] selenazole, naphtho [ 1 ,2-d ] selenazole, etc.), a tellurazole nucleus (e.g., benzotellurazole, 5-methylbenzotellurazole, 5,6-dimethylbenzotellurazole, 5-methylthiobenzotellurazole, 5-methoxybenzotellurazole, 5-hydroxybenzotellurazole, 5,6-dimethoxybenzotellurazole, naphtho [ 1 ,2-djtellurazole, 6-methoxy-8-me thylnaphtho [ 1 ,2-d ] tellurazole, 6-methoxynaphtho [ 1 ,2-d ] tellurnzole, etc.), a 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, 3,3,5trimethylindolenine, 3,3-dimethyl-5-chloroindolenine, etc.), an imidazole nucleus ,e.g., 1-alkylimidazole, 1 -alkyl-4-phenylimidazole, 1 -alkylbenzimidazole, 1 -alkyl-5-chlorobenzimidazole, 1-alkyl-5,6-di- chlorobenzimidazole, 1 -alkyl-5-methoxybenzimidazole, 1 -alkyl-5-cyanobenzimidazole, 1-alkyl-5-fluo- robenzimidazole, 1 -alkyl-5-trifluoromethylbenzimidazole, 1 -alkyl-6-chloro-5-cyanobenzimidazole, 1alkyl-6-chloro-5-trifluoromethylbenzimidazole, 1 -alkylnaphtho [ 1 ,2-d ] imidazole, 1 -allyl-5,6-dichloro- benzimidazole, 1 -allyl-5-chlorobenzimidazole, 1 -arylimidazole, 1 -arylbenzimidazole, 1-aryl-5-chloro- benzimidazole, 1-aryl-5 ,6-dichlorobenzimidazole, 1 -aryl-5-methoxybenzimidazole, 1-aryl-5-cyano- benzimidazole, 1-aryinaphtho- [ 1,2- ] imidazole, etc., wherein the above-described alkyl group is preferably an unsubstituted alkyl group having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, etc., or a hydroxyalkyl group such as a 2-hydroxyethyl group, a 3 hydroxypropyl group, etc., particularly preferably a methyl group or an ethyl group and the above-described. aryl group is a phenyl group, a halogen(e.g., chloro)-substituted phenyl group, an alkyl(e.g., methyl)-substituted phenyl group, an alkoxy(e.g., methoxy)-substituted phenyl group, etc.}, an imidazo [ 4,5-jquinoxaline nucleus (e.g., 1,3-diethylimidazo [ 4,5-b ] quinoxaline, 6-chloro-l ,3-diallylimidazo [ 4,5-b ] quinoxaline, etc.), an oxadiazole nucleus, a thiadiazole nucleus, a tetrazole nucleus, a pyrimidine nucleus, etc.

The alkyl group shown by R3 and R4 in the general formula (III) is an alkyl group having preferably 1 to 18 carbon atoms, more preferably 1 to 7 carbon atoms, particularly preferably 1 to 4 carbon atoms, and examples of the alkyl groups include unsubstituted alkyl groups (e.g., a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a hexyl group, an octyl group, a dodecyl group, an octadecyl group, etc.) and substituted alkyl groups lsuch as an aralkyl group (e.g., a benzyl group, a 2-phenylethyl group, etc.), a hydroxyalkyl group (e.g., a 2-hydroxyethyl group, a 3-hydroxypropyl group, etc.), a carboxyalkyl group (e.g., a 2-carboxyethyl group, a 3-carboxypropyl group, a 4-carboxybutyl group, a carboxymethyl group, etc.), an alkoxyalkyl group (e.g., a 2-methoxyethyl group, a 2-(2-methoxyethoxy)ethyl group, etc.), a sulfoalkyl group (e.g., a 2-sulfoethyl group, a 3-sulfopropyl group, a 3sulfobutyl group, a 4-sulfobutyl group, a 2- [ 3-sulfopropoxy ] ethyl group, a 2-hydroxy-3-sulfopropyl group, a 3-sulfopropoxyethoxyethyl group, etc.), a sulfatoalkyl group (e.g., a 3-sulfatopropyl group, a 4-sulfatobutyl group, etc.), a heterocyclic ring-substituted alkyl group (e.g., a 2-(pyrrolidin-2-on-lyl)ethyl group, a tetrahydrofurfuryl group, etc.), a 2-acetoxyethyl- group, a carboxymethoxymethyl group, a 2-methanesulfonylaminoethyl group and an allyl group (a vinyl methyl group)}.

Also, L', L2 and L3 in the general formula (III) represent a methine group which may be substituted by, for example, an unsubstituted or substituted alkyl group (e.g., a methyl group, an ethylbenzyl group, etc.), an aryl group (e.g., a phenyl group, etc.), a halogen atom (e.g., chlorine, bromine, etc.), a negative charge ketomethylene residue forming an aroholopolar cyanine dye, etc. Also, L', L2 or L3 may form a ring with other L.

Also, X1 in the general formula (III) represents an inorganic or organic acid anion such as chloride, bromide, iodide, p-toluenesulfonate, p-nitrobenzenesulfonate, methanesulfonate, methylsulfonate, ethylsulfonate, perchlorate, etc.

It is preferred that at least one of R3 and R4 in the general formula (III) described above is an alkyl group substituted by an acid group, such as a sulfoalkyl group, a carboxyalkyl group, etc.

The more preferred cyanine dyes for use in this invention are those represented by the following general formula (IV):

wherein Z3 and Z4, which may be the same or different, each represents an atomic group necessary for forming a 5-membered heterocyclic ring, which may be condensed, such as a thiazole nucleus, a benzothiazole nucleus, a naphthothiazole nucleus, a thiazoline nucleus, an oxazole nucleus, a benzoxazole nucleus, a naphthoxazole nucleus, an oxazoline nucleus, a selenazole nucleus, a benzoselenazole nucleus, a naphthoselenazole nucleus, a tellurazole nucleus, a 3,3-dialkylindolenine nucleus, an imidazole nucleus, an imidazo[4,5-b]quinoxaline nucleus, an oxadiazole nucleus, a thiadiazole nucleus, a tetrazole'nucleus, an isoxazole nucleus, etc.;R5 and R6 have the same significance as R3 and R4 in the general formula (III) above; at least one of R5 and R5 is an alkyl group substituted by an acid, such as a sulfoalkyl group, a carboxyalkyl group, etc.; L4, L5 and L6 have the same significance as L1, L2 and L3 in the general formula (III) described above; and p and q have the same significance as m and k, respectively, in the general formula (III).

The far more preferred cyanine dyes for use in this invention are those represented by the following general formula (V)

wherein 0' and Q2, which may be the same or different each represents -0-, -S-, -Se-, -Te-, or

(wherein R9 represents the alkyl group or the aryl group explained about the imidazole nucleus in the general formula (III) described above);

which may be the same or different, each represents a condensed heterocyclic ring, such as a benzothiazole nucleus, a naphthothiazole nucleus, a benzoxazole nucleus, a naphthoxazole nucleus, a benzoselenazole nucleus, a naphthoselenazole nucleus, a benzotellurazole nucleus, a naphthotellurazole nucleus, a benzimidazole nucleus, a naphthoimidazole nucleus, etc., which may be substituted;R7 and R8 have the same significance as R5 and R6 in the general formula (IV); L7, L8 and L6 have the same significance as Ll, L2 and L3 in the general formula (III) above; X39 has the same significance as Xl&commat;; and r and s have the same significance as m and k in the general formula (III).

In the general formula (V) described above,

which may be the same or different, each represents a condensed heterocyclic ring, which may be substituted. Examples of the heterocyclic ring are a benzothiazole nucleus (e.g., 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, 5phenethylbenzothiazole, 5-fluorobenzothiazole, 5-chloro-6-methylbenzothiazole, 5,6-dimethylbenzothiazole, 5-hydroxy-6-methylbenzothiazole, tetrahydrobenzothiazole, 4-phenylbenzothiazole, etc.), a naphthothiazole nucleus (e.g., naphtho [ 2,1-d ] thiazole, naphtho [ 1 ,2-d ] thiazole, naphtho[2,3-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, etc.), a benzoxazole nucleus (e.g;;, benzoxazole, 5chlorobenzoxazole, 5-methylbenzoxazole, 5-bromobenzoxazole, 5-fluorobenzoxazole, 5-phenylbenzoxazole, 5-methoxybenzoxazole, 5-nitrobenzoxazole, 5-trifluoromethylbenzoxazole, 5-hydroxyben- -zoxazole, 5-carboxybenzoxazole, 6-methylbenzoxazole, 6-chlorobenzoxazole, 6-nitrobenzoxazole, 6-methoxybenzoxazole, 6-hydroxybenzoxazole, 5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, 5-ethoxybenzoxazole, etc.), a naphthoxazole nucleus (e.g., naphtho [ 2,1-d ] oxazole, nphtho [ 1 ,2- djoxazole, naphtho(2,3-djoxazole, 5-nitronaphtho [ 2, l-d ] oxazole, etc.), a benzoselenazole nucleus (e.g., benzoselenazole, 5-chlorobenzoselenazole, 5-nitrobenzoselenazole, 5-methoxybenzoselenazole, 5-hydroxybenzoselenazole, 6-nitrobenzoselenazole, 5-chloro-6-nitrobenzoselanazole, etc.), a naphthoselenazole nucleus (e.g., naphtho [ 2, 1 -d ] selenazole, naphtho [ 1 ,2-d ] selenazole, etc.), a benzotellurazole nucleus (e.g., benzotellurazole, 5-methylbenzotellurazole, 5,6-dimethylbenzotellurazole, 5-methylthiobenzotellurazole, 5-methoxybenzotellurazole, 5-hydroxybenzotellurazole, 5,6-dimethoxybenzotellurazole, etc.), a naphthotellurazole nucleus (e.g., naphtho [ 1 ,2-d ] tellurazole, 6 methoxy-8-methylnaphtho [ 1 ,2-djtellurazole, 6-methoxynaphtho [ 1 ,2-d ] tellurazole, etc.), a benzimidazole nucleus or a naphthoimidazole nucleus {e.g., 1-alkylbenzimidazole, 1-alkyl-5-chlorobenzimida zole, 1 -alkyl-5,6-dichlorobenzimidazole, 1 -alkyl-5-methoxybenzimidazole, 1-alkyl-5-cyanobenzimida- zole, 1-alkyl-5-fluorobenzimidazole, 1 -alkyl-5-trifluoromethylbenzimidazole, 1 -alkyl-6-chloro-5-cya- nobenzimidazole, 1 -alkyl-6-chloro-5-trifluoromethylbenzimidazole, 1-alkyinaphtho [ 1,2-d ] imidazole, 1 -allyl-5,6-dichlorobenzimidazole, 1 -allyl-5-chlorobenzimidazole, 1 -arylbenzimidazole, 1 -aryl-5-chlo- robenzimidazole, 1 -aryl-5,6-dichlorobenzimidazole, 1 -aryl-5-methoxybenzimidazole, 1-aryl-5-cyano- benzimidazole, 1-aryinaphthot1,2-d ] imidazole, etc., wherein the above-described alkyl group is preferably an unsubstituted alkyl group having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, etc., or a hydroxyalkyl group such as a 2-hydroxyethyl group, a 3-hydroxypropyl group, etc., particularly preferably a methyl group or an ethyl group and the above described aryl group is a phenyl group, a halogen(e.g., chloro)-substituted phenyl group, an alkyl(e.g., methyl)-substituted phenyl group, an alkoxy(e.g., methoxy)-substituted phenyl group, etc.9.

In the general formula (V) described above, r represents preferably an integer of 1 to 3, more preferably 2. Furthermore, it is preferred in the general formula (V) that L7 and L9 represent =CH- and b represents -CH=, or an alkyl- or aryl-substituted methine group. It is further preferred that Q1 and Q2 represent -0- or -S- and L6 represents -CH=,

Then, specific examples of the cyanine dyes which can be used in this invention are illustrated below.

The cyanine dyes for use in this invention are known and can be easily produced based on the descriptions of F.M. Hamer, The Chemistry of Heterocyclic Compounds, (The Cyanine Dyes and Related Compounds), pages 86-199 (1964) (published by John Wiley & Sons, New York, London), and Japanese Patent Application (OPI) No. 78445/85.

The sensitizing dye(s) for use in this invention can be dispersed in a photographic emulsion directly or as a solution thereof in a proper solvent such as methanol, ethanol, methyl cellosolve, acetone, water, puridine or a mixed solvent thereof. Also, the dissolution of the sensitizing dye can be performed using ultrasonic waves.

As the addition method for the sensitizing dye, a method of dissolving the dye in a volatile organic solvent, dispersing the solution in an aqueous hydrophilic colloid solution and adding the dispersion to a photographic emulsion as described in U.S Patent 3,469,987; a method of dispersing the water-insoluble dye in a water-soluble solvent without being dissolved in an organic solvent and adding the dispersion to a photographic emulsion as described in Japanese Patent Publication No. 24185/71; a method of dissolving the dye in a surface active agent and adding the solution to a photographic emulsion as described in U.S.Patent 3,822,135; a method of disslving the dye in a solvent and adding the solution to a photographic emulsion as described in Japanese Patent Application (OPI) No. 74624/76; and a method of dissolving the dye in an acid substantially containing no water and adding the solution to a photographic emulsion as described in Japanese Patent Application (OPI) No. 80826/75 are used. Furthermore, other methods of adding dyes described in U.S. Patents 2,912,343, 3,342,605, 2,996,287, 3,429,835, etc., can be also used in this invention.

Also, the sensitizing dye described above may be uniformly dispersed in a silver halide emulsion before it is coated on a proper support; and in this case the dye may be dispersed therein in any step of preparing the silver halide emulsion.

That is, the sensitizing dye may exist in any step of producing the photographic emulsion or may be added in any step after production of the photographic emulsion before coating. For example, the dye may be added to a photographic emulsion in a step of forming the silver halide grains, a step of physical ripening or a step of chemical ripening.

The addition amount of the nitrogen-containing heterocyclic compound for use in this invention may be an amount sufficient for effectively increasing the sensitivity of the photographic emulsion. The amount can change in a wide range according to the emulsifying condition but is in the range of 1X10 5 to 1X10 2 mol, preferably 1X10 4 to 1X10-3 mol per mol of silver halide in the photographic emulsion.

The addition amount of the cyanine dye for use in this invention may be an amount sufficient for effectively increasing the sensitivity of the photographic emulsion. The amount can change in a wide range according to the emulsifying condition but is preferably in the range of 1 X 10-6 to 5X10-3 mol, in particular 3X10 6 to 2.5X10 mol, per mol of silver halide in the photographic emulsion.

Also, the ratio of the nitrogen-containing heterocyclic compound/cyanine dye giving a supersensitizing effect is preferably 0.05 to 10, particularly 0.1 to 3, by mol ratio.

For the photographic emulsions of this invention, silver bromide, silver iodobromide, silver iodochlorobromide, silver chlorobromide or silver chloride may be used. A preferred silver halide in this invention is silver iodobromide or silver iodochlorobromide containing less than 12 mol% silver iodide. A more preferred silver halide is silver iodobromide or silver iodochlorobromide containing 1 to 12 mol% silver iodide. A particularly preferred silver halide is silver iodobromide containing 2 mol% to 10 mol% silver iodide.

The silver halide grains in the photographic emulsion of this invention may have a regular crystal form such as cube, octahedron, or tetradecahedron, an irregular crystal form such as sphere, a crystal form having a crystal defect such as twin plane, etc., or a composite form thereof.

The silver halide grains may be fine grains having grain sizes of less than 0.1 ym or may be large grains having up to 10 jum in the projected area diameter. Also, the photographic emulsion of this invention may be a monodispersed emulsion having a narrow grain size distribution or a polydispersed emulsion having a broad grain size distribution.

The silver halide emulsion can be prepared according to a known method as described in Research Disclosure, No. 17643, pages 22-23 (December, 1978) "I. Emulsion Preparation and Types" and ibid., No. 18716, page 648 (November, 1979). Thus, the silver halide photographic emulsions of this invention can be prepared using the methods described in P. Glafkides, Chimie et Physique Photographique, published by Paul Montel, 1967; G.F. Duffin, Photographic Emulsion Chemistry, published by Focal Press, 1966; V.L. Zelikman et al., Making and Coating Photographic Emulsion, published by Focal Press, 1964, etc. That is, the photographic emulsion may be prepared by an acid method, a neutralization method, an ammonia method, etc., and as a method of reacting a soluble silver salt and a soluble halide, a single jet method, a double jet method, or a combination thereof can be used. A so-called reversal mixing method of forming silver halide grains in the existence of excessive silver ions can be also used. As one of the double jet methods, a so-called controlled double jet method of keeping constant pAg in the liquid phase of forming silver halide grains can be also used. According to the method, a silver halide emulsion wherein the silver halide grains have a regular crystal form and almost uniform grain size distribution.

A mixture of two or more kinds of silver halide emulsions separately prepared may be used.

The above-described silver halide emulsion containing regular silver halide grains can be obtained by controlling pAg and pH in the system during the formation of the silver halide grains.

These methods are described in detail, for example, in Photographic Science and Engineering, Vol. 6, 159-165 (1962), Journal of Photographic Science, Vol. 12, 242-251(1964), U.S.

Patent 3,655,394, and British Patent 1,413,748.

Also, a typical monodispersed emulsion contains silver halide grains having a mean grain diameter larger than about 0.1 micron, wherein at least 95% by weight of the silver halide grains have grain diameters within the mean grain diameter +40%. Also, a silver halide emulsion wherein the mean grain diameter is 0.25 to 2 microns and the grain diameters of at least 95% by weight or at least 950m by number of the silver halide grains are within the mean grain diameter +20% can be used in this invention. The production methods for these silver halide emulsions are described in U.S. Patents 3,574,628, 3,655,394, British Patent 1,413,748, etc.

Also, the monodispersed silver halide emulsions as described in Japanese Patent Application (OPI) Nos. 8600/73, 30027/76, 93097/76, 137133/78, 48521/79, 99419/79, 37635/83, 49938/83, etc., can be preferably used in this invention.

Tabular grain silver halide emulsion having an aspect ratio of at least 5 can be used in this invention. The above-described tabular silver halide grains can be easily prepared by the methods described in U.S. Patents 4,434,226, 4,414,310, 4,433,048, 4,439,520, British Patent 2,112,157, etc. In the case of using the tabular silver halide grains, the advantages such as the improvement of the color sensitizing efficiency by sensitizing dyes, the improvement of graininess, and the improvement of sharpness are obtained as described in the above-described U.S.

Patent 4,434,226.

Also, a so-called tabular grain silver halide emulsion can be preferably used in this invention.

The improvement of the color sensitizing efficiency in tabular grain silver halide emulsion is known and it is considered that the prevention of reduction in the intrinsic sensitivity (hereinafter, is referred to as intrinsic desensitization) at the addition of sensitizing dye(s) is accompanied by the great increase in sensitivity at color sensitization. It has now been discovered in this invention that by the use of the cyanine dye and the nitrogen-containing heterocyclic compound for the tabular grain silver halide emulsion, the intrinsic sensitivity and the sensitivity by color sensitization are astonishingly increased and at the same time the formation of fog in the case of the storage of the silver halide photographic materials can be prevented without reducing the sensitivity thereof.

Tabular grain silver halide emulsions having an aspect ratio of at least 5 can be used in this invention. Tabular silver halide grains having aspect ratio of 5 to 100 are preferred and tabular grains having aspect ratio of 5 to 20 are more preferred. The circle-corresponding diameter of the grains is preferably 0.2 ,cum to 30 ijm, more preferably 0.4 Am to 10 ,um. Also, the thickness of the tabular silver halide grains is preferably less than about 0.5 Am, more preferably less than about 0.3 im.

The crystal structure of silver halides for use in this invention may be uniform in halogen composition throughout the grains, may differ in halogen composition between the inside thereof and the outside thereof, or may be a layer structure. These silver halide grains are disclosed, for example, in British Patent 1,027,146, U.S. Patents 3,505,068, 4,444,877, and Japanese Patent Application No. 248469/83 (corresponding to Japanese Patent Application (OPI) No. 143331/85 and European Patent Application No. 147,854A2). In this invention, the silver halide grains having a structure of substantially two clear layers composed of a core portion of a high iodide content and a shell portion of a low iodide content (a core/shell structure) are particularly preferred.

Then, the silver halide grains having the clear layer structure are explained below in detail.

The clear layer structure can be decided by an X-ray diffraction method. The example of the application or an X-ray diffraction method for silver halide grains is described in H. Hirsh, Journal of Photographic Science, Vol. 10, page 129 infra (1962). If a lattice constant is determined by the halogen composition, the diffraction peak appears at the diffraction angle satisfying the Blagg condition (2d sineO=n.

The measurement method of X-ray diffraction is described in detail in Kisobunseki Kagaku Koza, 24, "X-Ray Bunseki", published by Kyoritsu Shuppan and X Ray Kaisetsu no Tebiki, published by Rigaku Denki K.K.

In the standard measurement method, copper (Cu) is used as the target and the diffraction curve of a (220) plane of a silver halide is obtained using the Kss ray of Cu as the X-ray source (tube voltage of 40 kv and tube current of 60 mA). For increasing the resolving power, it is necessary to confirm the measurement accuracy using a standard sample such as silicon by suitably selecting the width of slits (light-emitting sit, light-receiving slit, etc.), time constant of the apparatus, the scanning speed and recording speed of goniometer.

When a silver halide grain has a structure of two clear layers, there appear two peaks on the X-ray diffraction curve of the silver halide grain corresponding to the diffraction maximum by the silver halide in the high iodide layer and the diffraction maximum by the silver halide in the low iodide layer.

The silver halide grain structure of substantially two clear layers in this invention means the case that when the curve of the diffraction strength to the diffraction angle at the (220) plane of the silver halide is obtained using the Kss ray of Cu at a diffraction angle (20) in the range of 380 to 42 , there appear two diffraction maximums of the diffraction peak corresponding to the high iodide layer containing 10 to 45 mol% silver iodide and the diffraction peak corresponding to the low iodide layer containing at most 5 mol% silver iodide, and one diffraction minimum between the two diffraction maximums, and further the diffraction strength of the peak corresponding to the high iodide layer is 1/10 to 3/1 of the diffraction strength of the peak corresponding to the low iodide layer.The case that the above-described diffraction strength ratio is 1/5 to 3/1, particularly 1/3 to 3/1 is more preferred.

In the silver halide emulsion containing the silver halide grains having the structure of substantially two clear layers in this invention, it is more preferred that the diffraction strength of the minimum value between the two peaks is less than 90% of one of weaker diffraction strength of the two diffraction maximums (peaks). It is far more preferred that the aforesaid diffraction strength of the minimum value is less than 80%, particularly less than 60% of that of the maximum strength (peak) having weaker diffraction strength.

A means for resolving a diffraction curve composed of two diffraction components is well known and explained, for example, in Jikken Butsurigaku Koza, 11, "Koshi Kekkan", published by Kyoritsu Shuppan K.K.

It ia also useful to analyze the diffraction curve using a curve analyzer made by Du Pont de Nemours and Company by the assumption that the diffraction curve be a Gauss function or a Lorenz function.

In a silver halide emulsion containing two kinds of silver halide grains each having different halogen composition and each having no clear layer structure, two peaks appear. in the aforesaid X-ray diffraction. However, by such a silver- halide emulsion, the excellent photographic properties obtained by the present invention cannot be obtained.

For deciding whether a silver halide emulsion is the silver halide emulsion in this invention containing the silver halide grains having the layer structure of two clear layers or a silver halide emulsion containing two kinds of silver halide grains each having different halogen composition and having no clear layer structure, an EPMA method (Electron-Prove Micro Analyzer method) can be also used in place of the X-ray diffraction method.

In the EPMA method, a sample of a silver halide emulsion which is well-dispersed so that silver halide grains contained therein are not brought into contact with each other is-prepared and irradiated by an electron beam. Thus, the. elemental analysis at a very fine portion of the emulsion can be performed by the X-ray analysis by the electron beam excitation.

That is, by measuring the strengths of the characteristic X-rays of silver and iodine emitted from each silver grain according- to the method, the halogen composition of each silver halide grain can be determined.

Thus, by confirming the halogen compositions of at least 50 silver halide grains contained in a silver halide emulsion according to the EPMA method, it can be known whether or not the silver halide emulsion is the above-described emulsion in this invention.

It is preferred that in the silver halide emulsion of this invention, the iodide content of each silver halide grain is more uniform.

It is also preferred that when the iodide content distribution of the silver halide grains in a silver halide emulsion is measured by the EPMA method, the relative standard deviation is less than 50%, more preferably less than 35%, particularly preferably less than 20%.

Preferred halogen compositions of the silver halide grains having the clear layer structure are as follows.

The core portion of the silver halide grain is a high iodide content silver halide and it is better that the iodide content is in the range of 10 mol% to 45 mol% of the solid solution boundary.

The iodide content is preferably 15 to 45 mol%, more preferably 20 to 45 mol%.

In the core portion of the silver halide grain, the silver halide other than silver iodide may be silver chlorobromide or silver bromide but it is preferred that the content of silver bromide be higher.

The halogen composition of the outermost layer or the shell portion is a silver halide containing at most 5 mol% silver iodide, more preferably at most 2 mol% silver iodide. The- silver halide other than silver iodide in the outermost layer may be silver chloride, silver chlorobromide, or silver bromide but it is preferred that the content of silver bromide be higher.

In regard to the total halogen compositions, the effect of this invention becomes more remarkable when the content of silver iodide is less than 12 mol%, preferably 12 to 1 mol%, particularly preferably 10 to 2 mol%.

The silver halide emulsion containing the silver halide grains having the clear layer structure may have a broad grain size distribution of silver halides but the silver halide emulsion having a narrow grain size distribution is preferred. In particular, in the case of silver halide grains of a regular crystal form, a monodispersed silver halide emulsion wherein the silver halide grains having grain sizes within the mean grain size +40%, preferably within the mean grain size +30%, account for 90% of the total silver halide grains on weight or grain number is preferred.

The silver halide emulsion containing the silver halide grains having the clear layer structure can be prepared by various methods known in the field of photographic materials.

For obtaining preferred photographic properties using the silver halide emulsion composed of silver halide grains having the clear layer structure, the high iodide content silver halide in the core portion must be sufficiently covered by a low iodide content silver halide of the shell portion.

The necessary thickness of the shell layer depends upon the grain size of the silver halide but it is preferred that in the case of the silver halide having a large grain size of larger grain size of larger than 1.0 ,um, the silver halide is covered with the shell of the thickness of thicker than 0.1 ,um, and in the case of the silver halide having a small size of less than 1.0 Am, the silver halide is covered with the shell of the thickness of thicker than 0.05 Am.

For obtaining the silver halide emulsion composed of the silver halide grains having the clear layer structure, the silver content ratio of the core portion to the shell portion is preferably in the range of 1/5 to 5, more preferably in the range of 1/5 to 3, particularly preferably in the range of 1/5 to 2.

As already stated before in this specification, the structure of a silver halide grain having substantially two clear layers in the structure that two domains each having different halogen composition substantially exist in the silver halide grain, the central side of which is a core portion and the surface side thereof is a shell.

The term "substantially two" means that there may exist a third domain besides the core portion and the shell portion (for example, a layer existing between the central core portion and the shell portion of the outermost layer).

However, the aforesaid term means that even if such a third domain exits, it gives substantially no influence on the forms of the two peaks (two peaks corresponding to the high iodide portion and the low iodide portion) in the case of obtaining the X-ray diffraction pattern as described above.

That is, when a core portion of which iodide content, an intermediate portion, and a shell portion of low iodide content exist, the X-ray diffraction pattern has two peaks and one minimum portion between the two peaks; the X-ray diffraction strength corresponding to the high iodide portion is 1/10 to 3/1, preferably 1/5 to 3/1, more preferably 1/3 to 3/1 of that of the low iodide portion, and the X-ray diffraction strength of the minimum portion is less than 90%, preferably less than 80%, more preferably less than 70% of that of one of the two peaks having weaker diffraction strength, the silver halide grains are the grains having the structure of substantially clear two layers.

That is also true in the case that a third domain exists in the inside of the core portion.

Also, in the silver halide emulsion, silver halides each having different halide composition may be connected with each other by epitaxial connection or may be connected with other compound(s) than silver halide, such as, e.g., silver thiocyanate, lead oxide, etc. These silver halide emulsions are disclosed in U.S. Patents 4,094,684, 4,142,900, 4,459,353, British Patent 2,038,792, U.S. Patents 4,349,622, 4,395,478, 4,433,501, 4,463,087, 3,656,962, 3,852,067, Japanese Patent Application (OPI) No. 162540/84, etc.

Also, a mixture of silver halide grains having various crystal forms may be used.

The silver halide emulsion for use in this invention is usually physically ripened and chemically ripened. In these steps for the silver halide emulsions of this invention, the additives described in Research Disclosure, Nos. 17643 and 18716 can be used. That is, the photographic additives which can be used in this invention are shown in the following table.

Additive RD 17643 RD 18716 1. Chemical Sensitizer page 23 page 648, right column 2. Sensitization Increas ing Agent page 23 page 648, right column 3. Spectral Sensitizer pages 23-24 page 648, right column to page 649, right column 4. Antifoggant and pages 24-25 page 649, right column Stabilizer 5. Light Absorber, Filter pages 25-26 page 649, right column Dye, Ultraviolet to page 650, left Absorbent column 6. Stain Preventing Agent page 25, page 650, left column right column to right column 7. Hardening Agent page 26 page 650, left column 8. Binder page 26 page 650, left column 9. Plasticizer, Lubricant page 27 page 650, right column 10. Coating Aid, Surface page 26-27 page 650, right column Active Agent 11.Antistatic Agent page 27 page 650, right column In this invention, various kinds of color couplers can be used and specific examples of these color couplers are described in the above-described Research Disclosure (RD), No. 17643, VII-C to VII-G.

As dye-forming couplers, couplers giving three principal colors by subtraction color process (e.g., yellow, magenta, and cyan) by color development are important and specific examples of the nondiffusible 4-equivalent or 2-equivalent couplers are described in the above described Research Disclosure (RD), 17643, VII-C and Vll-D.

Furthermore, the following couplers can be preferably used in this invention.

That is, as yellow couplers hydrophobic acylacetamido series couplers having a ballast group are used in this invention. Specific examples of these couplers are described in U.S. Patents 2,407,210, 2,875,057 and 3,265,506. In this invention, the use of 2-equivalent couplers is preferred and specific examples of such couplers-are oxygen atom-releasing type yellow couplers described in U.S. Patents 3,408,194, 3,447,928, 3,933,501, and 4,022,620 and nitrogen atomreleasing type yellow couplers described in Japanese Patent Publication No. 10739/83, U.S.

Patents 4,401,752, 4,326,024, Research Disclosure, RD 18053 (April, 1979), British Patent 1,425,020, West German Patent Application (OLS) Nos. 2,219,917, 2,261,361, 2,329,587 and 2,433,812. Also, a-pivaloylacetanilide series yellow couplers are excellent in fastness, in particular, light fastness or colored dyes and, on the other hand, a-benzoylacetanilide yellow couplers give high coloring density.

As magenta couplers for use in this invention, there are hydrophobic indazolone series or cyanoacetyl series, preferably 5-pyrazolone series and pyrazoloazole series couplers having a ballast group. As the 5-pyrazolone series couplers, the couplers the 3-position of which is substituted by an arylamino group or an acylamino group are preferred from the viewpoint of the hue of the colored dyes and coloring density. Specific examples of these magenta couplers are described in U.S. Patents 2,311,082, 2,343,703, 2,600,788, 2,908,573, 3,062,653, 3,152,896, and 3,936,015.

As the releasable group for the 2-equivalent 5-pyrazolone series magenta couplers, the arylthio groups described in U.S. Patent 4,351,897 and the nitrogen atom-releasing group described in U.S. Patent 4,310,619 are particularly preferred. Also, the 5-pyrazolone series couplers having a ballast group described in European Patent 73,636 give high coloring density.

As the pyrazoloazole series couplers, there are pyrazolobenzimidazoles described in U.S. Patent 3,369,879, preferably pyrazolo [ 5,1-c ] [ 1,2,4 ] triazoles described in U.S. Patent 3,725"067 and the pyrazolotetrazoles described in Research Disclosure, 24220 (June, 1984) and Japanese Patent Application (OPI) No. 33552/85 and the pyrazolopyrazoles described in Research Disclosure, 24230 (June, 1984) and Japanese Patent Application (OPI) No. 43659/85. In the points of less yellow side absorption of colored dyes and light fastness of the colored dyes, the imidazoll,2- b]pyrazoles described in U.S Patent 4,500,630 are preferred and the pyrazolo [ 1 ,5-bj [ 1 ,2,4 ] tria- zoles described in European Patent 119,860A are particularly preferred.

As the cyan coupler for use in this invention, there are hydrophobic and nondiffusible naphtholic or phenolic couplers, such as the naphtholic couplers described in U.S. Patent 2,474,295 and, preferably the oxygen atom-releasing type 2-equivalent naphtholic couplers described in U.S. Patents 4,052,212, 4,146,396, 4,228,233 and 4,296,200.

Specific examples of the phenolic cyan couplers are described in U.S. Patents 2,369,929, 2,801,171, 2,772,162 and 2,895,826.

Cyan couplers having high fastness to humidity and temperature are preferably used in this invention and typical examples thereof are the phenolic cyan couplers having an alkyl group having at least 2 carbon atoms at the meta-position of the phenol nucleus described in U.S.

Patent 3,772,002, the 2,5-diacylamino-substituted phenolic couplers described in U.S. Patents 2,772,162, 3,758,308, 4,126,396, 4,335,011, 4,327,173, West German Patent Application (OLS) No. 3,329,729, and European Patent 121,365, and the phenolic couplers having a phenylureido group at the 2-position and an acylamino group at the 5-position described in U.S. Patent 3,446,622, 4,333,999, 4,451,559 and 4,427,767.

For correcting the unnecessary absorption of colored dye, it is preferred to perform masking by using colored coupler(s) for a color photographic material for photographing. Typical examples thereof are the yellow-colored magenta couplers described in U.S. Patent 4,163,670 and Japanese Patent Publication No. 39413/82 and the magenta-colored cyan couplers described in U.S.

Patents 4,004,929, 4,138,253, and British Patent 1,146,368. Other colored couplers described in Research Disclosure, 17643, VII-G can be also used in this invention.

The graininess can be improved by using smearing dye-forming couplers of which the colored dye has a proper diffusibility together with the above-described couplers. Specific examples of these couplers are described in U.S. Patent 4,366,237 and British Patent 2,125,570 for magenta couplers and in European Patent 96,570 and West German Patent Application (OLS) No.

3,234,533 for yellow, magenta and cyan couplers.

The dye-forming couplers and the above-described specific couplers may form dimer or more polymers. Typical examples of the polymerized dye-forming couplers are described in U.S.

Patents 3,451,820 and 4,080,211. Also, specific examples of polymerized magenta coupler are described in British Patent 2,102,173 and U.S. Patent 4,367,282.

Couplers releasing photographically useful residue with coupling can be preferably used in this invention. Also, the DIR couplers releasing development inhibitor described in Research Disclosure, No. 17643, VII-F are useful in this invention.

Also, the developer inactivating type couplers described in Japanese Patent Application (OPI) No. 151944/82, the timing type couplers described in U.S. Patent 4,248,962, the reaction type couplers described in Japanese Patent Application No. 39653/84 (corresponding to Japanese Patent Application (OPI) No. 184248/85), the developer inactivating tyep DIR couplers described in Japanese Patent Application (OPI) Nos. 151944/82, 217932/83, Japanese Patent Application Nos. 75474/84, 82214/84 and 90438/84 (corresponding to Japanese Patent Application (OPI) Nos. 218644/85, 225156/85 and 233650/85, respectively), and the reaction type DIR couplers described in Japanese Patent Application No. 39653/84 (corresponding to Japanese Patent Application (OPI) No. 184248/85) can be preferably used as a combination with the abovedescribed components in this invention.

Proper supports which are used for the photographic light-sensitive materials having the photographic emulsion of this invention are described in Research Disclosure, No. 17643, page 28 and ibid., No. 18716, page 647, right column to page 648, left column.

As the photographic light-sensitive materials for which the photographic emulsions of this invention can be applied, there are various kinds of color and black-and-white light-sensitive materials. For example, there are photographing color negative films (for general use, cinne film, etc.), color reversal films (for slide, for cinne film or there may be a case containing no coupler), color photographic papers, color positive films (for cinne film, etc.), color reversal photographic papers, heat-developable color light-sensitive materials, color light-sensitive materials using silver dye bleaching process, photographic light-sensitive materials for photomechanical process (lithographic films, scanner films, etc.), X-ray photographic light-sensitive materials (for direct or indirect medical treatment, for industry, etc.), photographing black-and-white negative films, black-and-white photographic papers, light-sensitive materials for microfilm (for COM, microfilms, etc.), color diffusion transfer light-sensitive materials (DTR), silver salt diffusion transfer lightsensitive materials, print out light-sensitive materials, etc.

The light exposure for obtaining photographic images by the photographic light-sensitive materials using the silver halide photographic emulsions of this invention may be performed using an ordinary method. That is, known various light sources such as natural light (sunlight), a tungsten lamp, a fluorescent lamp, a mercury lamp, a xenon arc lamp, a carbon arc lamp, a xenon flash lamp, a cathode ray tube flying spot, a light-emitting diode, laser light (e.g., gas laser, YAG laser, dye laser, semiconductor laser), etc., can be used. Also, the photographic light-sensitive materials may be light exposed by light emitted from phosphor excited by electron beam, X-rays, gamma rays, alpha rays, etc.The exposure time may be from 1/1,000 sec to 1 sec for an ordinary camera use as well as may be shorter than 1/1,000 sec as 1/1or to 1/106 sec in the case of using a xenon flash lamp or a cathode ray tube, or may be longer than 1 sec.

If necessary, the spectral composition of light may be controlled by using color filter(s).

The photographic light-sensitive materials for which the photographic emulsions of this invention are applied can be processed by the ordinary process described in Research Disclosure, No.

17643, pages 28 and 29 and ibid., No. 18716, page 651, right column to left column.

The following examples are intended to illustrate this invention more practically but not to limit it in any way.

EXAMPLE 1 Sample 101 of a multilayer color light-sensitive material was prepared by forming the following layers on a cellulose triacetate film support having subbing layer.

Compositions of the Light-Sensitive Layers: In the following light-sensitive emulsion layers, the coated amounts of silver halide and colloid silver are shown by g/m2 unit of silver, the coated amounts of a coupler, additives and gelatin are shown by g/m2 unit, and the coating amount of a sensitizing dye is shown by mol number per mol of silver halide in the same layer.

Layer 1: Antihalation Layer Black Colloid Silver 0.2 Gelatin 1.3 Colored Coupler C- 1 0.06 Ultraviolet Absorbent UV-1 0.1 Ultraviolet Absorbent UV-2 0.2 Dispersion Oil, Oil-1 0.01 Dispersion Oil, Oil-2 0.01 Layer 2: Interlayer Gelatin 1.0 Colored Coupler C-2 0.02 Dispersion Oil, 01-1 0.1 Layer 3: First Red-Sensitive Emulsion Layer Silver lodobromide Emulsion 0.4 (silver iodide 2 mol%, mean grain size: 0.3 ,am) Gelatin 0.6 Sensitizing Dye S-23 1 OX 10 4 Sensitizing Dye S-34 3.0X10-4 Sensitizing Dye S-41 1 X 10 Coupler C-3 0.06 Coupler C-4 0.06 Coupler C-8 0.04 Coupler C-2 0.03 Dispersion Oil, Oil-I 0.03 Dispersion Oil, Oil-3 0.012 Layer 4: Second Red-Sensitive Emulsion Layer Silver lodobromide Emulsion 0.7 (silver iodide: 5 mol%, mean grain size: 0.5 Am Sensitizing Dye S-23 1X10-4 Sensitizing Dye S-34 3X10-4 Sensitizing Dye S-41 1X10-5 Coupler C-3 0.24 Coupler C-4 0.24 Coupler C-8 0.04 Coupler C-2 0.04 Dispersion Oil, Oil-1 0.15 Dispersion Oil, Oil-3 0.02 Layer 5: Third Red-Sensitive Emulsion Layer Silver lodobromide Emulsion 1.0 (silver iodide: 6 mol%, mean grain size: 0.7 Am) Gelatin 1.0 Sensitizing Dye S-23 1X10-4 Sensitizing Dye S-34 3X10-4 Sensitizing Dye S-41 1 X 10-5 Coupler C-6 0.05 Coupler C-7 0.1 Dispersion Oil, 01-1 0.1 Dispersion Oil, OiI-2 0.05 Layer 6:Interlayer Gelatin 1.0 Compound Cpd-A 0.03 Dispersion Oil, Oil-1 0.05 Dispersion Oil, Oil-2 0.05 Layer 7: First Green-Sensitive Emulsion Layer Silver lodobromide Emulsion 0.30 (silver iodide: 4 mol%, mean grain size: 0.3 ,um) Sensitizing Dye S- 18 5X10-4 Sensitizing Dye S-47 2X10-4 Sensitizing Dye S-20 0.3 X 10-4 Gelatin 1.0 Coupler C-9 0.2 Coupler C-S 0.03 Coupler C-1 0.03 Dispersion Oil, Oil-1 0.5 Layer 8:Second Green-Sensitive Emulsion Layer Silver lodobromide Emulsion 0.4 (silver iodide: 5 mol%, mean grain size: 0.5 Am) Sensitizing Dye S- 18 5 X 10-4 Sensitizing Dye S-47 2X104 Sensitizing Dye S-20 0.3X10 4 Coupler C-9 0.25 Coupler C-1 0.03 Coupler C-10 0.015 Coupler C-S 0.01 Dispersion Oil, Oil-1 0.2 Layer 9:Third Green-Sensitive Emulsion Layer Silver lodobromide Emulsion 0.85 (silver iodide: 6 mol%, mean grain size: 0.7 m) Gelatin 1.0 Sensitizing Dye S-17 3.5X10 4 Sensitizing Dye S-58 1.4X10-4 Coupler C-li 0.01 Coupler C-12 0.03 Coupler C- 13 0.20 Coupler C-l 0.02 Coupler C-15 0.02 Dispersion Oil, Oil-1 0.20 Dispersion Oil, Oil-2 0.05 Layer 10:Yellow Filter Layer Gelatin 1.2 Yellow Colloid Silver 0.08 Compound Cpd-B 0.1 Dispersion Oil, Oil-l 0.3 Layer 1 I: First Blue-Sensitive Emulsion Layer Monodispersed Silver lodobromide 0.4 Emulsion -(silver iodide: 4 mol%, mean grain size: 0.3 Am) Gelatin 1.0 Sensitizing Dye S-5 2X 10-4 Coupler S- 14 0.9 Coupler C-5 0.07 Dispersion Oil, Oil-1 0.2 Layer 12: Second Blue-Sensitive Emulsion Layer Silver lodobromide Emulsion 0.5 (silver iodide: 10 mol%, mean grain size: 1.5 Hm) Gelatin 0.6 Sensitizing S-5 1X10-4 Coupler C-14 0.25 Dispersion Oil, Oil-1 0.07 Layer 13:First Protective Layer Gelatin 0.8 Ultraviolet Absorbent UV-1 0.1 Ultraviolet Absorbent UV-2 0.2 Dispersion Oil, Oil-l 0.01 Dispersion Oil, Oil-2 0.01 Layer 14: Second Protective Layer Fine Grain Silver Bromide 0.5 (mean grain size: 0.07 Am) Gelatin 0.45 Polymethyl Methacrylate Particles 0.2 (diameter: 1.5 clam) Hardening Agent H-1 0.4 Formaldehyde Scavenger, Scav-1 0.5 Formaldehyde Scavenger, Scav-2 0.5 Each layer described above further contained a surface active agent as a coating aid in addition to the above-described components. Thus, Sample 101 was prepared.

Then, the compounds used in this example are shown below by the chemical compositions or the chemical names:

x/y = 7/3 (weight ratio)

Oil-1: Tricresyl Phosphate Oil-2: Dibutyl Phthalate Oil-3: Bis(2-ethylhexyl) Phthalate C-1

n/m+m' = 1 (weight ratio) m/m' = 2 (weight ratio) molecular weight: about 50,000

The photographic material thus prepared was exposed to a tungsten light source, the color temperature of which was controlled to 4,800"K at 25 CMS and then processed at 38"C according to the following processing steps.

Color Development 3 min 15 sec Bleach 6 min 30 sec Wash 2 min 10 sec Fix 4 min 20 sec Wash 3 min 15 sec Stabilization 1 min 05 sec The compositibns of the processing solutions used in the above steps were as follows.

Color Developer Diethylenetriaminepentaacetic Acid 1.0 1 -Hydroxyethylidene- 1,1 -diphosphonic 2.0 g Acid Sodium Sulfite 4.0 g Potassium Carbonate 30.0 g Potassium Bromide 1.4 g Potassium lodide 1.3 mg Hydroxylamine Sulfate 2.4 g 4-(N-Ethyl-N-ss-hydroxyethylamino)-2- 4.5 g methylaniline Sulfate Water to make 1.0 liter pH adjusted to 10.0 Bleaching Solution: Ammonium Ethylenediaminetetraacetato 100.0 g Ferrate Ethylenediaminetetraacetic Acid 10.0 g Disodium Salt Ammonium Bromide 150.0 g Ammonium Nitrate 10.0 g Water to make 1.0 liter pH adjusted to 6.0 Fixing Solution: Ethylenediaminetetraacetic Disodium salt 1.0 g Sodium Sulfite 4.0 g Aqueous Solution of Ammonium 175.0 ml Thiosulfate (70%) Sodium Hydrogensulfite 4.6 g Water to make 1.0 liter pH adjusted to 6.6 Stabilization Solution:: Formalin (40%) 2.0 ml Polyoxyethylene-p-monononyl Phenyl 0.3 g Ether (mean polymerization degree: about 10) Water to make 1.0 liter Then, each of Samples 102 to 110 was prepared by following the same procedure as the case of preparing Sample 101 except that the compound of this invention shown in Table 1 below or the Comparison Compound A shown below was added to Layer 5 of Sample 101 as shown in Table 1 below and each of the samples was light-exposed and processed as the case of Sample 101.

Comparison Compound A;

The fog and the sensitivity of each sample in fresh performance (directly after preparation of the sample) were measured and the results are shown in Table 1 below using the results of Sample 101 as the standards.

Also, in other test, after storing Samples 101 to 110 for 3 days at 600C and 30% RH (relative humidity), each sample was similarly light-exposed and processed, and the fog and the sensitivity were measured on each sample. The results thus obtained are also shown in Table 1 below using the results of Sample 101 directly after preparation as the standards.

T A B L E 1 After Storage Fresh Performance for 3 Days Relative Relative Sample Compound Amount Fog Sensitivity Fog Sensitivity (mol/mol Ag) 101 -- -- #0* 100** +0.20 70 102 (1) 0.7 x 10-4 -0.01 102 +0.09 98 103 (1) 2.0 x 10-4 -0.02 105 +0.05 102 104 (1) 6.0 x 10-4 -0.02 120 +0.01 115 105 A 0.7 x 10-4 -0.02 99 +0.06 82 106 A 2.0 x 10-4 -0.04 95 #0 90 107 A 6.0 x 10-4 -0.07 40 -0.05 32 108 (3) 2.0 x 10-4 -0.01 114 +0.02 109 109 (7) 6.0 x 10-4 -0.03 110 #0 107 110 (10) 6.0 x 10-4 -0.04 107 -0.01 102 Compounds (1), (3), (7) and (10) are the nitrogen-containing heterocyclic compounds in this invention shown hereinbefore and Compound A is the abovedescribed comparison compound. * and ** are standard values.

From the results shown in Table 1, it can be seen that Samples 102, 103, 104, 108, 109 and 110 containing each compound of this invention shown by the general formula (I) described above show low fog and high sensitivity as compared with those of Sample 101 containing no compound of the general formula (I) and also the change of the performance after storing for 3 days at 600C and 30% RH are less in the above samples of this invention. Such effects were not obtained in Comparison Samples 105, 106 and 107 each containing Comparison Compound A which was not substituted by -COOM or -SO3M.

EXAMPLE 2 Samples 111 to 119 were prepared by following the same procedure as the case of preparing Sample 101 in Example 1 except that the compound of this invention shown by the general formula (I) or Comparison Compound A shown above in Example 1 was added to Layer 9 of Sample 101 as shown in Table 2 below and after exposing and processing these samples, the fog and sensitivity were measured on each sample as in Example 1. The results thus obtained are shown in Table 2 below.

T A B L E 2 After Storage Fresh Performance for 3 Days Relative Relative Sample Compound Amount Fog Sensitivity Fog Sensitivity (mol/mol Ag) 101 -- -- #0* 100** +0.16 74 111 (1) 0.7 x 10-4 -0.02 100 +0.09 90 112 (1) 2.0 x 10-4 -0.03 102 +0.04 98 113 (1) 6.0 x 10-4 -0.03 110 #0.0 106 114 A 0.7 x 10-4 -0.02 97 +0.05 91 115 A 2.0 x 10-4 -0.05 83 +0.01 80 116 A 6.0 x 10-4 -0.05 56 -0.02 44 117 (3) 6.0 x 10-4 -0.02 111 #0.0 107 118 (7) 6.0 x 10-4 -0.03 107 -0.01 104 119 (10) 6.0 x 10-4 -0.04 109 -0.02 107 Compounds (1), (3), (7) and (10) are the compounds shown by general formula (I) described above and Compound A is the comparison compound described in Example 1.

* and ** are standard values shown in Table 1 of Example 1.

From the results shown in Table 2, it can be seen that Samples 111, 112, 113, 117. 118 and 119 containing the compound of this invention shown by the general formula (I) described above show low fog, high sensitivity and improved storability as compared with Sample 101 containing no compound shown by the general formula (I), Sample 101 being the comparison sample shown in Example 1. Also, such effects were not obtained in Comparison Samples 114, 115 and 116 containing Comparison Compound A which was not substituted by -COOM or -SO3M.

EXAMPLE 3 Samples 120 to 126 were prepared by following the same procedure as the case of preparing Sample 101 in Example 1 except that the compound of this invention shown by the general formula (I) or Comparison Compound A described in Example 1 was added to Layer 12 of Sample 101 and after expsoing and processing these samples as in Example 1, the fog and sensitivity were measured on each sample. The results thus obtained are shown in Table 3 below.

T A B L E 3 After Storage Fresh Performance for 3 Days Relative Relative Sample Compound Amount Fog Sensitivity Fog Sensitivity (mol/mol Ag) 101 -- -- #0.0* 100** +0.15 76 120 (1) 6.0 x 10-4 -0.01 109 +0.03 105 121 A 0.7 x 10-4 -0.01 97 +0.05 91 122 A 2.0 x 10-4 -0.03 88 #0.0 84 123 A 6.0 x 10-4 -0.04 60 -0.03 57 124 (3) 6.0 x 10-4 -0.01 105 +0.02 102 125 (7) 6.0 x 10-4 -0.01 107 +0.03 105 126 (10) 6.0 x 10-4 -0.01 107 +0.03 104 Compounds (1), (3), (7) and (10) are the compounds shown by general formula (I) and Compound A is the comparison compound described in Example 1.

* and ** are standard values as in Example 1.

From the results shown in Table 3, it can be seen that Samples 120, 124, 125 and 126 containing the compound of this invention shown by the general formula (I) described above show low fog, high sensitivity, and improved storability as compared with Sampel 101 containing no compound of the general formula (I) described in Example 1. Also, such effects were not obtained in Comparison Samples 121, 122 and 123 containing Comparison Cornpound A.

EXAMPLE 4 To the silver odobroinide emulsion containing 6 mol% silver iodide as used for Layer 5 of Sample 101 in Example 1 was added the cyanine dye and each of the nitrogen-containing heterocyclic compounds (i.e., the compounds of this invention represented by the general formula (I) shown above and Comparison Compounds B to J shown below) shown in Table 4 below as a solution thereof in a proper solvent such as water or methanol and after adding thereto a coupler dispersion composed of Couplers C-6 and C-7, Dispersion Oils, Oil-l and Oil-2 and gelatin as used for Layer 5 in Example 1, the resultant mixture was coated on a support together with a gelatin protective layer containing Hardening Agent H-l as used in Example 1.

Thus, Samples 201 to 230 were prepared, which samples each contains a photosensitive layer and a protective layer. In this case, the coated amounts for silver and couplers were 2.0 g/m2 for silver, 0.15 g/m2 for Coupler C-6, and 0.30 g/m2 for Coupler C-7.

Each of the samples thus prepared was exposed to a tungsten light, the color temperature of which was controlled to 4,800 K with a filter at 10 CMS with using an optical filter SC-50 (for measuring color sensitized sensitivity) made by Fuji Photo Film Co., Ltd., or an optical filter BPN42 (for measuring intrinsic sensitivity) made by the same company.

These samples were processed as in Example 1 except that the time for the color development was changed to 2 min 45 sec and then the fog and sensitivities were measured. The results thus obtained are shown in Table 4 below.

In addition, in Table 4, the fog was shown as the values obtained and the intrinsic sensitivity and the color sensitized sensitivity were shown as relative values using the sensitivites (log E) of Sample 203.

In addition, the comparison compounds used in Example 4 are shown below.

T A B L E 4 Nitrogen-Containing Photographic Property Heterocyclic (A)* (B)* (C)*4 Cyanine Dye Compound Sample Kind Amount* Kind Amount* Alog E Alog E 201 -- -- -- -- 0.18 +0.06 -202 S-34 2.0 -- -- 0.21 +0.04 -0.12 203 " 3.0 -- -- 0.22 #0*5 #0*5 204 " 4.0 -- -- 0.18 -0.13 -0.07 205 " 3.0 (1) 2.0 0.18 +0.02 +0.04 206 " " " 6.0 0.17 +0.04 +0.09 207 " " (10) 2.0 0.18 +0.02 +0.03 208 " " " 6.0 0.17 +0.02 +0.03 209 " " (13) 2.0 0.23 +0.02 +0.02 210 " " " 6.0 0.25 +0.04 #0.0 211 " " (14) 2.0 0.23 +0.02 +0.01 212 " " " 6.0 0.25 +0.03 +0.02 213 " " B 2.0 0.12 -0.08 -0.12 214 " " " 6.0 0.07 -0.32 -0.38 (cont'd) Nitrogen-Containing Photographic Property Heterocyclic (A)* (B)* (C)*4 Cyanine Dye Compound Sample Kind Amount* Kind Amount* Alog E Alog E 215 S-34 3.0 C 2.0 0.09 -0.10 -0.11 216 " " " 6.0 0.06 -0.22 -0.28 217 " " D 2.0 0.13 -0.02 -0.04 218 " " " 6.0 0.09 -0.06 -0.10 219 " " E 2.0 0.09 -0.06 -0.03 220 " " " 6.0 0.05 -0.29 -0.25 221 " " F 2.0 0.11 -0.04 -0.06 222 " " " 6.0 0.07 -0.14 -0.20 223 " " G 2.0 0.10 -0.04 -0.06 224 " " " 6.0 0.07 -0.14 -0.16 225 " " H 2.0 0.16 0.0 -0.04 226 " " " 6.0 0.09 -0.10 -0.16 227 " " I 2.0 0.15 -0.16 -0.19 228 " " " 6.0 0.09 -0.55 -0.60 229 " " J 2.0 0.11 -0.15 -0.16 230 " " " 6.0 0.09 -0.34 -0.38 Note: "1: X10-4 mol/mol Ag *2: Fog *3: Intrinsic sensitivity *4: Color sensitized sensitivity *5:Standard From the results shown in Table 4, it can be seen that the supersensitizing effect by the mercapto compounds having a tetrazole nucleus shown by the general formula (I) described above is larger than other mercapto compound having -COOM or -SO3M as substituent. In particular, the compound shown by the general formula (II) described above are preferred in the point of giving low fog.

EXAMPLE 5 By following the same procedure as in Example 4 except that the tetraazaindene compound shown in Table 5 was further added to the photosensitive layer of each of Samples 201, 203, and 206, Samples 201', 203' and 206' were respectively prepared.

The samples thus prepared were light-exposed and processed as in Example 4 and the fog and sensitivities were measured as in Example 4. The results thus obtained are shown in Table 5 below.

In addition, the sensitivities were shown by relative sensitivities using those of Sample 203 as the standards.

T A B L E 5 N-Containing Photographic Property Heterocyclic (A)* (B)*4 (C)*5 Cyanine Dye Compound Tetraazaindene Sample Kind Amount* Kind Amount* Kind Amount* Alog E Alog E 201 -- -- -- -- -- -- 0.18 +0.06 -203 S-34 3.0 -- -- -- -- 0.22 #0 #0 206 " 3.0 (1) 6.0 -- -- 0.17 +0.04 +0.09 201' -- -- -- -- (X)*6 2.0 0.19 +0.07 -203' S-34 3.0 -- -- " 2.0 0.23 +0.03 +0.03 206' " 3.0 (1) 6.0 " 2.0 0.18 +0.06 +0.11 *1: x 10-4 mol/mol Ag *2: x 10-3 mol/mol Ag *3: Fog *4: Intrinsic sensitivity *5: Color sensitized sensitivity

As is clear from the results shown in Table 5, the effect of this invention can be also obtained in the presence of a tetraazaindene (such as (X) shown above).Also, as shown in the results of Table 5, better results are obtained by using the tetraazaindene together with the nitrogen-containing heterocyclic compound of this invention shown by the general formula (I) described above.

EXAMPLE 6 The silver iodide content in the silver iodobromide emulsion used for Sample 201 in Example 4 was 6 mol%. In this example, the silver iodide content in the silver iodobromide emulsion for Sample 201 was changed while the mean grain size of the silver halide grains was kept at 0.7 ,um and the effects of the silver halide content were determined. The results obtained are shown in Table 6.

T A B L E 6 Silver Photographic Property Iodide Cyanine Dye Mercapto Compound (A)* (B)* (C)*4 Sample Content Kind Amount* Kind Amount* Alog E Alog E 201 6 mol% -- -- -- -- 0.18 +0.06 -203 " S-34 3.0 -- -- 0.22 #0 #0 206 " " " (1) 6.0 0.17 +0.04 +0.09 231 8 mol% -- -- -- -- 0.17 +0.08 -232 " S-34 3.0 -- -- 0.21 #0 -0.01 233 " " " (1) 6.0 0.17 +0.05 +0.06 234 10 mol% -- -- -- -- 0.16 +0.10 -235 " S-34 3.0 -- -- 0.19 -0.01 -0.02 236 " " " (1) 6.0 0.17 +0.03 +0.03 237 12 mol% -- -- -- -- 0.16 +0.10 -238 " S-34 3.0 -- -- 0.19 -0.04 -0.05 239 " " " (1) 6.0 0.18 -0.02 +0.01 240 14 mol% -- -- -- -- 0.17 +0.08 -241 " S-34 3.0 -- -- 0.19 -0.08 -0.07 242 " " " (1) 6.0 0.19 -0.07 -0.06 243 16 mol% -- -- -- -- 0.18 +0.04 -244 " S-34 3.0 -- -- 0.19 -0.20 -0.18 245 " " " (1) 6.0 0.19 -0.22 -0.16 In Table 6 above: *1:X10-4 mol/mol Ag *2: Fog *3: Intrinsic sensitivity *4: Color sensitized sensitivity As is shown in the results of Table 6, it is preferred that the silver iodide content in the silver halide emulsions which are used in this invention together with the nitrogen-containing heterocyclic compounds shown by the general formula (I) is less than 12 mol%. As shown in the above results, with the increase of the silver iodide content, the effect of the supersensitization by the nitrogen-containing heterocyclic compound of the general formula (I) becomes lower.

EXAMPLE 7 By following the same procedure as in Example 4 except that the cyanine dye and each of the nitrogen-containing heterocyclic compounds shown in Table 7 below were used for the photosensitive layer of Sample 201 in Example 4, Samples 246 to 256 were prepared.

The samples thus prepared were exposed and processed as in Example 4 and the fog and sensitivities were measured. The results are shown in Table 7.

In addition, the sensitivities in Table 7 were shown as relative values using those of Sample 247 as the standards.

T A B L E 7 H-Containing Photographic Property Heterocyclic (A)* (B)* (C)*4 Cyanine Dye Compound Sample Kind Amount* Kind Amount* Alog E Alog E 201 -- -- -- -- 0.18 +0.06 -246 S-64 0.3 -- -- 0.20 +0.03 -0.20 247 " 0.5 -- -- 0.21 #0*5 #0*5 248 " 0.7 -- -- 0.19 -0.13 -0.12 249 " 0.5 (1) 2.0 0.19 +0.01 +0.04 250 " " " 6.0 0.17 +0.03 +0.08 251 " " A 2.0 0.18 -0.18 -0.15 252 " " " 6.0 0.16 -0.30 -0.27 253 " " D 2.0 0.20 -0.03 -0.04 254 " " " 6.0 0.18 -0.07 -0.11 255 " " K 2.0 0.21 -0.05 -0.06 256 " " " 6.0 0.18 -0.10 -0.13 *1: x 10-4 mol/mol Ag, *2: Fog, *3: Intrinsic sensitivity, *4: Color sensitized sensitivity, *5: Standard In addition, Comparison Compounds A, D and K used in this example are the same as those used in Example 1 and Example 4 described above.

As shown in the results of Table 7, it can be seen that in the case of using the cyanine dye, Samples 249 and 250 of this invention containing the nitrogen-containing compound shown by the general formula (I) show greatly improved supersensitizing effect in the intrinsic sensitivity region and the color sensitization region while keeping low fog as compared with Samples 251 to 256 using Comparison Compounds A, D and K, respectively.

EXAMPLE 8 By following the same procedure as in Example 4 except that the mean grain sizes of the silver iodobromide emulsions in the silver halide emulsion layers for Sample 201 were equally adjusted to 0.7 um and the silver halide grain structure was changed as shown in Table 8 below, Samples 257 to 280 were prepared and the effects thereof were determined.

These samples obtained were image-exposed and processed as in Example 4 and the photographic properties were measured as in Example 4. The results obtained are shown in Table 8.

In addition, in the table, the sensitivity values are shown by relative values with that of Sample 258 as the standard.

T A B L E 8 Silver Mercapto Photographic Property Iodide Core/Shell Cyanine Dye Compound (A)* (E)*4 (C)*5 Sample Content (I)/(II)*; Ratio Kind Amount* Kind Amount* Alog E Alog E 257 5 mol% 5 mol% Uniform -- -- -- -- 0.18 +0.05 - (uniform) 258 " " " S-34 3.0 -- -- 0.23 #0*6 #0*6 259 " " " " 3.0 (1) 6.0 0.18 +0.02 +0.07 260 " " " " 3.0 (7) " 0.19 +0.01 +0.06 261 " 15 mol%/0 mol% 1/2 -- -- ~~ ~~ 0.22 +0.05 -262 " " " S-34 3.0 -- -- 0.26 +0.01 +0.02 263 " " " " " (1) 6.0 0.18 +0.04 +0.10 264 " " " " " (7) " 0.19 +0.03 +0.08 265 9 mol% 9 mol% Uniform -- -- -- -- 0.16 +0.09 - (uniform) 266 " " " S-34 3.0 -- -- 0.20 -0.01 -0.02 267 " " " " " (1) 6.0 0.17 +0.03 +0.02 268 " " " " " (7) " 0.18 +0.02 +0.02 269 " 27 mol%/0 mol% 1/2 -- -- -- -- 0.21 +0.10 - (cont'd) Silver Mercapto Photographic Property Iodide Core/Shell Cyanine Dye Compound (A)* (B)*4 (C)*5 Sample Content (I)/(II)* Ratio Kind Amount* Kind Amount*2 Alog E Alog E 270 9 mol% 17 mol%/0 mol% 1/2 S-34 3.0 -- -- 0.25 #0 -0.01 271 " " " " " (1) 6.0 0.17 +0.06 +0.07 272 " " " " " (7) " 0.18 +0.06 +0.06 273 15 mol% 15 mol % Uniform -- -- -- -- 0.17 +0.05 - (uniform) 274 " " " S-34 3.0 -- -- 0.19 -0.18 -0.15 275 " " " " " (1) 6.0 0.18 -0.20 -0.14 276 " " " " " (7) " 0.19 -0.19 -0.13 277 " 40 mol%/0 mol% 1/1.7 -- -- -- -- 0.19 +0.05 -278 " " " S-34 3.0 -- -- 0.21 -0.12 -0.10 279 " " " " " (1) 6.0 0.19 -0.13 -0.09 280 " " " " " (7) " 0.19 -0.13 -0.10 In Table 8 described above: *1: (I): Silver iodide content of the core portion (ill): Silver iodide content of the shell portion *2: Amount (X10-4 mol/mol Ag) *3: Fog *4: Intrinsic Sensitivity *5:Color Sensitized sensitivity *6: Standard As shown in the results of Table 8 above, it can be seen that the supersensitizing effects in the intrinsic sensitivity region and the color sensitizing region are remarkable by the use of the silver halide grains having the layer structure composed of a high iodide core portion and a low iodide shell portion (a core/shell structure).

EXAMPLE 9 By following the same procedure as Example 4 except that the volume of the silver iodobromide grains in the silver halide emulsion layers used for Sample 201 was adjusted at a constant value, the aspect ratio of the tabular silver halide grains was changed, and also the contents of the cyanine dye and the mercapto compound were changed as shown in Table 9 below, Samples 281 to 289 were prepared and the effects thereof were determined.

The aspect ratio of the tabular silver halide grains used was obtained as follows. As the diameter of the tabular silver halide grain, the diameter of the circle of the same area as the projected area of the silver halide grain was measured. Also, as the thickness of the silver halide grain, the distance of the two parallel planes constituting the tabular silver halide grain was measured. The ratio of the circle-corresponding diameter to the thickness of the silver halide grains was employed as the aspect ratio.

These samples were image-exposed and processed as in Example 4 and the photographic properties thereof were measured as in the same example. The results thus obtained are shown in Table 9.

In addition, the sensitivity values shown in the table are shown by the relative values with that of Sample 282 as a standard.

T A B L E 9 Silver Mercapto Photographic Property Iodide Aspect Cyanine Dye Compound (A)* (B)* (C)*4 Sample Content Ratio Kind Amount* Kind Amount* Alog E Alog E 281 4 mol% 3 -- -- -- -- 0.19 +0.03 -282 " " S-34 3.0 -- -- 0.24 #0*5 #0*5 283 " " " " (1) 6.0 0.17 +0.01 +0.07 284 " 6 -- -- -- -- 0.19 +0.03 -285 " " S-34 3.8 -- -- 0.24 -0.02 +0.02 286 " " " " (1) 7.6 0.17 +0.02 +0.13 287 " 10 -- -- -- -- 0.18 +0.03 -288 " " S-34 4.8 -- -- 0.25 -0.03 +0.04 289 " " " " (1) 9.6 0.18 +0.03 +0.19 *1: Amount (x 10-4 mol/mol Ag) *2: Fog *3: Intrinsic sensitivity *4: Color sensitized sesitivity *5: Standard As shown in Table 9, it can be seen that the supersensitizing effect in the intrinsic sensitivity region and the color sensitizing region is remarkable in the case of using the tabular silver halide grains having a high aspect ratio.

Now, as described above, by using the nitrogen-containing heterocyclic compound shown in the general formula (I) shown above and a cyanine dye, the silver halide emulsion containing them can be spectrally sensitized by supersensitization.

In the case of using a conventional mercapto-containing nitrogen-containing heterocyclic compound having an acid group, an effect of development inhibition occurs but in the case of using the nitrogen-containing heterocyclic compound shown by the general formula (I) according to this invention, such a trouble does not occur, whereby a remarkable supersensitizing effect can be obtained.

Also, the supersensitizing effect of this invention is sufficiently obtained even after storing the silver halide emulsion containing them for a long period of time as well as the effect is obtained in the intrinsic sensitivity region and the color sensitizing region in such a case.

Furthermore, the supersensitizing effect in this invention is further increased in the coexistence of a tetraazaindene with the above-described components of this invention, in the silver halide emulsion having a silver iodide content of less than 12 mol%, in the silver halide emulsion composed of the silver halide grains having the layer structure of a high iodide core portion and a low iodide shell portion (a core/shell structure), or in the high aspect ratio silver halide emulsion (aspect ratio of at least 5).

Claims (16)

1. A silver halide photographic emulsion containing a nitrogen-containing heterocyclic compound represented by the following general formula (I) and a cyanine dye as a combination thereof

wherein R' represents an aliphatic group, an aromatic group or a heterocyclic group; each of said groups being substituted by at least one -COOM or -SO3M (wherein M represents a hydrogen atom, an alkali metal atom, a quaternary ammonium or a quaternary phosphonium).

2. The silver halide photographic emulsion as claimed in Claim 1, wherein the nitrongecontaining heterocyclic compound is a compound represented by the following general formula (II)

wherein R2 represents a phenyl group substituted by at least one -COOM or-SO3M (wherein M represents a hydrogen atom, an alkali metal atom, a quaternary ammonium or a quaternary phosphonium.

3. The silver halide photographic emulsion as claimed in Claim 1, wherein the silver halide contained in the silver halide emulsion contains less than 12 mol% silver iodide.

4. The silver halide photographic emulsion as claimed in Claim 1, wherein the silver halide contained in the silver halide emulsion contains less than 12 mol% silver iodide and has a core/shell structure.

5. The silver halide photographic emulsion as claimed in Claim 1, wherein the silver halide contained in the silver halide emulsion is the tabular silver halide grains having an aspect ratio of at least 5.

6. The silver halide photographic emulsion as claimed in Claim 1, wherein the cyanine dye is a compound represented by the following general formula (III)

wherein Z' and Z2 each represents an atomic group necessary for forming a 5-membered or 6membered heterocyclic ring, which may be condensed; R3 and R4, which may be the same or different, each represents an alkyl group which may be substituted; LX, L2 and L3, which may be the same or different, each represents a methine group which may be substituted; X,9 represents an acid anion; k represents 1 or 2; and m represents an integer of 1 to 4; when k is 1, said compound forms an intramolecular salt.

7. The silver halide photographic emulsion as claimed in Claim 1, wherein the cyanine dye is a compound represented by the following general formula (IV)

wherein Z3 and Z4, which may be the same or different, each represents an atomic group necessary for forming a 5-membered heterocyclic ring which may be condensed; R5 and R6, which may be the same or different, each represents an alkyl group which may be substituted; at least one of said R5 and R6 being an alkyl group substituted by an acid group; L4, L5 and L6, which may be the same or different, each represents a methine group which may be substituted; X28 represents an acid anion; p represents an integer of 1 to 4; and q represents 1 or 2; when q is 1, said compound forms an intramolecular salt.

8. The silver halide photographic emulsion as claimed in Claim 7, wherein said 5-membered heterocyclic ring is a thiazole nucleus, a benzothiazole nucleus, a naphthothiazole nucleus, a thiazoline nucleus, an oxazole nucleus, a benzoxazole nucleus, a naphthoxazole nucleus, an oxazoline nucleus, a selenazole nucleus, a benzoselenazole nucleus, a naphthoselenazole nucleus, a tellurazole nucleus, a 3,3-dialkylindolenine nucleus, an imidazole nucleus, an imidazo[4,5-b]quinoxaline nucleus, an oxadiazole nucleus; a thiadiazole nucleus, a tetrazole nucleus, or an isoxazole nucleus.

9. The silver halide photographic emulsion as claimed in Claim 7, wherein said acid group is a sulfoalkyl group or a carboxyalkyl group.

10. The silver halide photographic emulsion as claimed in Claim 1, wherein the cyanine dye is a compound represented by the following general formula (V)

wherein Q and Q2, which may be the same or different, each represents -0-, -S-, -Se-, -Teor

(wherein R9 represents an alkyl group or an aryl group);

which may be the same or different, each represents a condensed heterocyclic ring, which may be substituted; R7 and R8, which may be the same or different, each represents an alkyl group which may be substituted; at least one of said R7 and Ra being an alkyl group which may be substituted by acid group;L7, L8 and Lg, which may be the same or different, each represents a methine group which may be substituted; X3t represents an acid anion; r represents an integer of 1 to 4; and s represents 1 or 2; when s is 1 said compound forms an intramolecular salt.

11. The silver halide photographic emulsion as claimed in Claim 10, wherein said condensed heterocyclic ring is a benzothiazole nucleus, a naphthothiazole nucleus, a benzoxazole nucleus, a naphthoxazole nucleus, a benzoselenazole nucleus, a naphthoselenazole nucleus, a benzotellurazole nucleus, a naphthotellurazole nucleus, a benzimidazole nucleus or a naphthoimidazole nucleus.

12. The silver halide photographic emulsion as claimed in Claim 10, wherein r in the general formula showing the cyanine dye is an integer of 1 to 3.

13. The silver halide photographic emulsion as claimed in Claim 10, wherein r in the general formula showing the cyanine dye is 2.

14. The silver halide photographic emulsion as claimed in Claim 10, wherein L7 and L9 represent =CH- and L8 represents -CH= or a methine group substituted by alkyl group or an aryl group.

15. The silver halide photographic emulsion as claimed in Claim 1, wherein the addition amounts of the nitrogen-containing heterocyclic compound and the cyanine dye are 0.05 to 10 in the heterocyclic compound/the cyanine dye in mol ratio.

16. The silver halide photographic emulsion as claimed in Claim 1, wherein the addition amounts of the nitrogen-containing heterocyclic compound and the cyanine dye are 0.1 to 3 in the heterocyclic compound/the cyanine dye in mol ratio.