Silver halide photographic material containing a yellow coupler and a phosphorus compound and color image forming method

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FIELD OF THE INVENTION

This invention relates to a photographic material and more particularly to a silver halide color photographic material having improved reactivity of a yellow coupler with the oxidation product of a color developing agent (hereinafter referred to as color formability) and improved image stability. It also relates to a color image forming method using said photographic material.

BACKGROUND OF THE INVENTION

When silver halide photographic materials are exposed to light and then subjected to color development processing, aromatic primary amine developing agents oxidized by silver halide are reacted with color couplers, whereby color image can be formed.

As yellow couplers, there are known four-equivalent type couplers and .alpha.-acylacetanilides where one hydrogen atom of active methylene group is substituted by an aryloxy group, a halogen atom, sulfoxy group, an acyloxy group, etc., described in JP-A-50-87650 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), U.S. Pat. Nos. 3,369,695, 3,408,194, 3,415,652 and 3,447,928. These couplers have disadvantages in that coupling reaction activity is low and image fastness is poor.

When color formability is insufficient, there are problems that photographic characteristics are greatly varied by changed in the components of developing solutions and images of stable quality can not be obtained. When image fastness is poor, the quality of image is deteriorated during storage. Thus, it is highly demanded to improve image fastness.

As yellow couplers which are more active and freed from the above problems, there are known couplers wherein one hydrogen atom of active methylene group is directly substituted by a nitrogen-containing heterocyclic ring, described in JP-A-47 26133.

However, when these couplers are used, yellow color image is not considered to be fully satisfying with respect to fastness under light and moisture and heat conditions, though formability is improved.

It is highly demanded to reduce the amount of washing water or stabilizing solution from the viewpoint of the preservation of the environment. When the amount is reduced (for example, by a method described in JP-A-57-8543), image fastness is greatly deteriorated. Thus, it is eagerly demanded to find out a method for improving yellow image fastness.

Hindered amines and hindered phenol compounds are described as stabilizers for yellow image in British Patents 1,326,889, 1,354,313 and 1,410,846.

However, effects obtained by these compounds are still unsatisfactory, though the fastness of yellow image is somewhat improved.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a silver halide color photographic material which is excellent in color formability and has improved yellow image fastness.

The inventors have made studies to achieve the above-described object and found that the above-described object can be achieved by providing a silver halide color photographic material containing at least one of yellow couplers represented by the following general formula (I) and at least one of compounds represented by the following general formula (A-I). ##STR10##

In the formula (I), R.sup.1 represents a substituted or unsubstituted N-phenylcarbamoyl group; R.sup.2 represents an alkyl group or an aryl group; Xl represents a group represented by the following formula (a), (b), (c) or (d). ##STR11##

In the formulae (a) and (b), R.sup.3 and R.sup.4, which may be the same or different, each is a hydrogen atom, a halogen atom, a carboxylic ester group, an amino group, an alkyl group, an alkylthio group, an alkoxy group, an alkylsulfonyl group, an alkylsulfinyl group, a carboxyl group, a sulfonic acid group or a salt thereof, a substituted or unsubstituted phenyl group or a heterocyclic group. ##STR12##

In the formula (c), W.sup.1 is a non-metallic atom for forming a four-membered, five-membered or six-memebered ring together with the moiety ##STR13## in the group of the formula (c). ##STR14##

In the formula (d), R.sup.0 represents an N arylcarbamoyl group. ##STR15##

In the formula (A-I), R represents --(Y).sub.n --R'; Y represents --O--, --S--, --NH-- or ##STR16## n is 0 or 1; R' and R", which may be the same or different, each is a residue of a phosphoric acid; and Q represents a divalent group of the following formula (A-I-1). ##STR17##

In the formula (A-I-1), A is an atomic group which forms a substituted or unsubstituted benzene ring; X is a single bond, a substituted or unsubstituted methylene group, --S--, --O--, --NH--, ##STR18## --SO.sub.2 -- or --SO--; and R'", is a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, a heterocyclic group, an acyl group or a sulfonyl group.

Free bonds in the formula (A-I-1) represent the bonding positions to O atoms at the position of Q in the formula (A-I).

DETAILED DESCRIPTION OF THE INVENTION

The two-equivalent type couplers for use in the present invention are the compounds represented by the formula (I) and are illustrated in more detail below.

In the formula (I), R.sup.1 is a substituted or unsubstituted N-phenylcarbamoyl group, substituent groups for said N-phenylcarbamoyl group may be conventional groups for yellow couplers. Examples of the substituent groups include an alkyl group, an alkenyl group, an alkoxy group, an alkoxycarbonyl group, a halogen atom, an alkoxycarbamoyl group, an aliphatic amido group, an alkylsulfamoyl group, an alkylsulfonamido group, an alkylureido group, an alkyl-substituted succinimido group, an aryloxy group, an aryloxycarbonyl group, an arylcarbamoyl group, an arylamido group, an arylsulfamoyl group, an arylsulfonamido group, an arylureido group, a carboxyl group, a sulfo group, a nitro group, a cyano group and a thiocyano group. The substituted N-phenylcarbamoyl group may have two or more substituent groups. These two or more substituent groups may be the same or different.

When R.sup.2 is an alkyl group, a tertiary alkyl group having from 4 to 20 carbon atoms is preferred. Examples of the alkyl group include t-butyl, t-amyl, t-ocyl, 1,1-diethylpropyl, 1,1-dimethylhexyl and 1,1,5,5-tetramethylhexyl. Typical examples of substituent groups for the substituted alkyl group and the substituted aryl group are those already described above in the definition of R.sup.1.

The coupling off group represented by X.sup.1 is a group which is released by coupling to form a two-equivalent type coupler. Namely, the group X.sup.1 is a group represented by the following formula (a), (b), (c) or (d). ##STR19##

In the formulae (a) and (b), R.sup.3 and R.sup.4, which may be the same or different, each is a hydrogen atom, a halogen atom, a carboxylic ester group, an amino group, an alkyl group, an alkylthio group, an alkoxy group, an alkylsulfonyl group, an alkylsulfinyl group, a carboxyl group, a sulfonic acid group or a salt thereof (e.g., an alkali metal salt or ammonium salt thereof), an unsubstituted or substituted phenyl group or a heterocyclic group. ##STR20##

In the formula (c), W' is a non-metallic atom required for forming a four-membered, five-membered or six-memebered ring together with the moiety ##STR21## in the formula (c). ##STR22##

In the formula (d), R.sup.0 represents an N-aryl carbamoyl group.

Preferred examples of compounds which can be used as the yellow couplers in the present invention include compounds represented by the following general formula. (I'). ##STR23##

In the formula (I'), R.sup.9 is a tertiary alkyl group having from 4 to 12 carbon atoms, or a phenyl group which may be substituted by a halogen atom, an alkyl group or an alkoxy group; R.sup.10 is a halogen atom or an alkoxy group; R.sup.11 is a hydrogen atom, a halogen atom or an alkoxy group which may be optionally substituted; R.sup.12 is an acylamino group which may be optionally substituted, an alkoxycarbonyl group, an alkylsulfamoyl group, an acylsulfamoyl group, an arylsulfamoyl group, an alkylsulfonamido group, an arylsulfonamide group, an alkylureido group, an arylureido group, a succinimido group, an alkoxy group or an aryloxy group; and X.sup.2 is a group represented by the following general formula (e), (f), (g) or (h). ##STR24##

In the formulae (e), (f) and (g), R.sup.13 and R.sup.14 each is a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group or a hydroxyl group; R.sup.15, R.sup.16 and R.sup.17 each is a hydrogen atom, an alkyl group, an aryl group, an aralkyl group or an acyl group; and W.sup.2 is an oxygen atom or a sulfur atom.

Particularly preferred examples of the yellow couplers which can be used in the present invention are compounds represented by the following general formula (I"). ##STR25##

In the formula (I"), R.sup.18 is a substituted or unsubstituted alkyl group or phenyl group; and X.sup.2 is the group represented by the formula (e), (f) or (g) as set forth in the formula (I').

These yellow couplers can be synthesized according to methods described in JP-B-51-10783 (the term "JP-B" as used herein means an "examined Japanese patent publication"), JP-B-51-33410, JP-B-51-33410, JP-A-47-26133, JP-A-48-73147, JP-A-51-102636, JP-A-52-82424, JP-A-52-115219, British Patent 1,425,020 and West German Patent 1,547,868.

Concrete examples of the yellow couplers represented by the formula (I) include, but are not limited to, the following compounds. ##STR26##

The groups of the compounds represented by the formula (A-I) will be illustrated in more detail below.

The residue of a phosphoric acid represented by R' and R" means a residue of a phosphoric ester which constitutes the compounds of the formula (A I). Examples of the residue include an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, a heterocyclic group and an acyl group.

Among the compounds of the formula (A-I), compounds where n is 0 or 1 and Y is --O-- are preferred from the viewpoint of the effect of the present invention.

The groups represented by the formula (A-I-I) will be illustrated in more detail below.

Among the groups represented by the formula (A-I1), groups represented by the following general formula (A-I-2) are preferred. ##STR27##

In the formula (A-I-2), free bonds and X are the same as those set forth in the formula (A-I-1); and R.sup.5, R.sup.6, R.sup.7 and R.sup.8 each is a hydrogen atom or a substituent group.

The groups R.sup.5, R.sup.6, R.sup.7, R.sup.8 and X in the formula (A-I 2) will be illustrated in more detail below.

In the formula (A-I-2), R.sup.5, R.sup.6, R.sup.7 and R.sup.8 each is a hydrogen atom or a substituent group. Preferred examples of the substituent group include an aliphatic group, an aromatic group (e.g., phenyl, naphthyl), a heterocyclic ring (e.g., 2-pyridyl, 2-tetrahydropyranyl), a halogen atom (e.g., fluorine, chlorine, bromine), an aliphatic oxy group (e.g, methoxy, butoxy), an acyloxy group (e.g., acetoxy, benzoyloxy), a sulfonyloxy group (e.g., benzenesulfonyloxy), an acylamino group (e.g., acetylamino, benzoylamino), a sulfonamido group (e.g., methanesulfonamido), an amino group, an aliphatic or aromatic oxycarbonyl group (e.g., phenoxycarbonyl, butoxycarbonyl), a carbamoyl group (e.g., dimethylcarbamoyl, phenylcarbamoyl) and a hydroxy group.

X is preferably a substituted or unsubstituted methylene group (e.g., methylene, isopropylidene), an acyl bond, an oxygen atom, a sulfur atom, a sulfonyl bond or an amino group.

The term "aliphatic group" as used herein means a straight-chain, branched or cyclic aliphatic hydro carbon group including a saturated or unsaturated group such as an alkyl group, an alkenyl group and an alkynyl group. Typical examples of the aliphatic group include methyl, ethyl, butyl, dodecyl, octadecyl, eicosenyl, isopropyl, tert-butyl, tert-octyl, tert-dodecyl, cyclo hexyl, cyclopentyl, allyl, vinyl, 2-hexadecenyl and propargyl groups.

Among the above-described substituent groups, groups which can be further substituted may be optionally substituted by further substituent groups such as an alkyl group, an aryl group, a heterocyclic group, an alkoxy group (e.g., methoxy, 2-methoxyethoxy), an aryloxy group (e.g., 2,4-di tert-amylphenoxy, 2-chlorophenoxy, 4-cyanophenoxy), an alkenyloxy (e.g., 2propenyloxy), an acyl group (e.g., acetyl, benzoyl), an ester group (e.g., butoxycarbonyl, phenoxycarbonyl, acetoxy, benzoyloxy, butoxysulfonyl, toluenesulfonyloxy), an amido group (e.g., acetylamino, ethylcarbamoyl, dimethylcarbamoyl, methanesulfonamido, butylsulfamoyl), a sulfamido group (e.g., dipropylsulfamoylamino), an imido group (e.g., succinimido, hydantoinyl), an ureido group (e.g., phenylureido, dimethylureido), an aliphatic or aromatic sulfonyl group (e.g., methanesulfonyl, phenylsulfonyl), an aliphatic or aromatic thio group (e.g., ethylthio, phenylthio), a hydroxyl group, a cyano group, a carboxyl group, a nitro group, a sulfo group and a halogen atom.

Concrete examples of the compounds represented by the formula (A-I) include, but are not limited to, the following compounds.

__________________________________________________________________________ ##STR28## Compound Q R __________________________________________________________________________ A-1 ##STR29## OC.sub.4 H.sub.9 A-2 " ##STR30## A-3 " OC.sub.8 H.sub.17 A-4 " OC.sub.12 H.sub.25 A-5 " OC.sub.16 H.sub.33 A-6 " OC.sub.18 H.sub.37 A-7 " ##STR31## A-8 " ##STR32## A-9 " ##STR33## A-10 " ##STR34## A-11 ##STR35## ##STR36## A-12 " ##STR37## A-13 " ##STR38## A-14 " OCH.sub.2 CH.sub.2 OC.sub.4 H.sub.9 A-15 " SC.sub.8 H.sub.17 A-16 " ##STR39## A-17 " NHC.sub.4 H.sub.9 A-18 " ##STR40## A-19 " ##STR41## A-20 " ##STR42## A-21 ##STR43## ##STR44## A-22 " C.sub.8 H.sub.17 A-23 " ##STR45## A-24 ##STR46## OCH.sub.3 A-25 " ##STR47## A-26 " ##STR48## A-27 " OC.sub.9 H.sub.19 (i) A-28 " OC.sub.13 H.sub.27 (i) A-29 ##STR49## ##STR50## A-30 " OCH.sub.2 CH.sub.2 Cl A-31 " ##STR51## A-32 " ##STR52## A-33 " ##STR53## A-34 " SC.sub.6 H.sub.13 A-35 " ##STR54## A-36 " NHC.sub.8 H.sub.17 A-37 " ##STR55## A-38 " ##STR56## A-39 ##STR57## C.sub.10 H.sub.21 A-40 ##STR58## OC.sub.6 H.sub.13 A-41 " ##STR59## A-42 " OC.sub.18 H.sub.37 (i) A-43 " O(CH.sub.2 ) .sub.8CHCH.sub.2 A-44 " ##STR60## A-45 ##STR61## ##STR62## A-46 " ##STR63## A-47 " SC.sub.16 H.sub.33 A-48 " ##STR64## A-49 " ##STR65## A-50 " C.sub.6 H.sub.13 A-51 ##STR66## OC.sub.3 H.sub.7 A-52 ##STR67## OC.sub.8 H.sub.17 A-53 " OC.sub.13 H.sub.27 (i) A-54 " ##STR68## A-55 " ##STR69## A-56 " ##STR70## A-57 " ##STR71## A-58 " ##STR72## A-59 " ##STR73## A-60 ##STR74## ##STR75## A-61 " ##STR76## A-62 " OC.sub.16 H.sub.33 A-63 " ##STR77## A-64 " ##STR78## A-65 " ##STR79## A-66 ##STR80## C.sub.8 H.sub.17 A-67 ##STR81## ##STR82## A-68 ##STR83## " A-69 ##STR84## " A-70 ##STR85## " A-71 ##STR86## ##STR87## A-72 ##STR88## ##STR89## A-73 ##STR90## " A-74 ##STR91## " A-75 ##STR92## OC.sub.4 H.sub.9 A-76 " ##STR93## A-77 " ##STR94## A-78 ##STR95## OCH.sub.3 A-79 ##STR96## ##STR97## A-80 ##STR98## ##STR99## A-81 ##STR100## " __________________________________________________________________________

The compounds represented by the formula (A-I) can be easily synthesized as follows. That is, first bisphenols are synthesized according to methods described in U.S. Pat. Nos. 2,735,765 and 3,700,455 and JP-A-62-262047 and then the resulting bisphenols react with phosphorus oxychloride, or phosphoric acid or phosphorous acid dichloride according to methods described in the literature "Organophosphorus Compounds", John Wiley & Sons, Inc., New York, 1950, p. 226, p. 228, U.S. Pat. Nos. 3,209,021 and 4,278,757.

Preferably, 1.times.10.sup.-3 to 1 mol, more preferably 5.times.10.sup.-2 to 5.times.10.sup.-1 mol (per mol of silver halide existing in the same layer) of the coupler of the formula (I) is added to emulsion layer.

Preferably 1 to 200 mol %, more preferably 2 to 30 mol % (based on the coupler of the formula (I)) of the compound of the formula (A-I) is added.

In the practice of the present invention, it is preferred that the lipophilic coupler of the formula (I) and the compound of the formula (A-I) are dissolved in or impregnated with lipophilic fine particles. Materials constituting the lipophilic fine particles are oily solvents (including solid at room temperature such as wax) for additives such as the coupler in addition to said compound, or materials serving as additives as well as oily solvents such as polymer, coupler, antistain agent, ultraviolet light absorber, etc.

The term "lipophilic fine particles" mean fine particles which are substantially insoluble in aqueous gelatin solution and exist as a separate phase in the aqueous gelatin solution.

The lipophilic fine particles of the present invention can be generally prepared by dissolving the coupler having the formula (I) and the compound having the formula (A-I) in a high-boiling solvent (oil) having a boiling point of not lower than 170.degree. C. under atmospheric pressure, or a low-boiling solvent (when oil is not required) or a mixed solvent of said oil and said low-boiling solvent and then emulsifying the resulting solution in an aqueous solution of hydrophilic colloid such as gelatin. Thought there is no particular limitation with regard to the particle diameter (grain size) of the lipophilic fine particle, a particle diameter of 0.05 to 0.5 .mu.m, particularly 0.1 to 0.3 .mu.m is preferred.

The ratio of said oil/said coupler is in the range of preferably 0.01 to 4.0 by weight.

It is preferred that lipophilic fine particles are formed by the compound having the formula (A-I) together with at least one of phenolic cyan couplers or diphenylimidazole cyan couplers and at least one of water-insoluble but organic solvent-soluble homopolymers or copolymers and an emulsion of said fine particles is mixed with silver halide emulsion and used. Namely, a color photograph obtained by using a color photographic material containing such a silver halide emulsion is excellent in color image preservability even under high temperature and humidity conditions and can exhibit good color image-preservability even in the case where replenishment rate per unit area of the silver halide color photographic material to be processed in the water washing stage or stabilizing stage is as very low as 0.5 to 50 times the amount of carried over (brought over) from the previous bath in a processing method comprising carrying out the water washing stage or stabilizing stage after desilverization subsequent to the color development processing.

A similar effect can be achieved by the following silver halide color photographic material. Namely, said material is a silver halide color photographic material comprising red-sensitive, green-sensitive and blue-sensitive silver halide emulsion layers provided on a support, wherein at least one of said compounds having the formula (A-I) is contained in at least one layer containing a color coupler, at least one of compounds having the formula (III) is contained in at least one layer of light-insensitive gelatin-containing layers and at least one of compounds having the following formula (U-II) is contained in at least one layer containing a color coupler. ##STR101##

In the formula (III), R.sup.7, R.sup.8, R.sup.9, R.sup.10 and R.sup.11, which may be the same or different, each is a hydrogen atom, a halogen atom, a nitro group, a hydroxyl group, an alkyl group, an alkenyl group, an aryl group, an alkoxy group, an acyloxy group, an aryloxy group, an alkylthio group, an arylthio group, a mono- or dialkylamino group, an acylamino group or a five-membered or six-membered oxygen or nitrogen-containing heterocyclic group. R.sup.10 and R.sup.11 may be combined together to form a five-membered or six-membered aromatic ring composed of carbon atoms. ##STR102##

In the formula (U-II), R.sup.1 and R.sup.2, which may be the same or different, each is an alkyl group; R' is a substituted or unsubstituted alkyl group or aryl group.

The color photographic material of the present invention comprises at least one blue-sensitive silver halide emulsion layer, at least one green sensitive silver halide emulsion layer and at least one red-sensitive silver halide emulsion layer provided on a support. In conventional color photographic paper, said layers are coated in the above-described order on the support. If desired, said layers may be coated in different order. An infrared-sensitive silver halide emulsion layer can be used in place of at least one of the above-described emulsion layers. Color reproduction by subtractive color photography can be made by incorporating silver halide emulsions having sensitivity to each wave range and couplers in these sensitive emulsion layers, said couplers forming dyes having a complementary color relationship to light for exposure (namely, yellow image to blue light, magenta image to green light and cyan image to red light). If desired the photographic material is so constituted that the sensitive layers do not have the above-described relationship with the developed hues of the couplers.

As the silver halide for the silver halide emulsion of the present invention, silver iodobromide and silver chloroiodobromide are preferred and the preferred content of silver iodide is 1 to 15 mol %, when the silver halide emulsion is used for color photographic material for photographing, while a silver halide emulsion comprising silver chloride or silver chlorobromide containing substantially no silver iodide (substantially free from silver iodide) is preferred, when the emulsion is used for color printing photo graphic material.

The term "containing substantially no silver iodide" or "substantially free from silver halide" as used herein means that the content of silver iodide is not higher than 1 mol%, preferably not higher than 0.2 mol %. The halogen composition of the emulsion may be different among grains or the grains are equal in the halogen composition. However, when emulsions comprising grains equal in the halogen composition are used, the property of each grain can be easily homogenized. With regard to the distribution of halogen composition in the interior of silver halide emulsion grains, there can be used any of uniform structure type grain wherein any area of silver halide grains is equal in its composition; integral structure type grain wherein core in the interior of the silver halide grain is different in halogen composition from shell (a single layer or multi-layer) surrounding the core; and grain having such a structure that a non-laminar area having a different halogen composition is formed in the interior of the grain or on the surface of the grain (when formed on the surface of the grain, the area having a different composition is joined to the edge, corner or surface of the grain). For the purpose of providing high sensitivity, the above-described second and third grain structures are preferable to the uniform structure type grain and they are preferred from the viewpoint of pressure resistance. When the silver halide grains have the above-described structures, the boundary between the areas having different halogen compositions may be clear or indistinct by the formation of a mixed crystal due to a difference in the composition, or structural change may be continuous.

With regard to the halogen composition of the silver chlorobromide emulsion, the ratio of silver bromide/silver chloride can be widely varied according to the purpose of use, but the content of silver chloride of not lower than 2 mol% is preferred.

High-silver chloride emulsions having a high silver chloride content are preferred for photographic materials suitable for use in rapid processing. The silver chloride contents of these high-silver chloride emulsions are preferably not lower than 90 mol %, more preferably not lower than 95 mol %.

It is preferred that the high-silver chloride emulsion has such a layered or non-layered structure that a silver bromide-localized phase exists in the interior and/or on the surface of the silver halide grain. The halogen composition of said localized phase is such that the content of silver bromide is preferably at least 10 mol %, more preferably higher than 20 mol %. These localized phases may exist in the interiors of the grains or on the edge, corners or surfaces of the grains. In a preferred embodiment, the localized phases are formed on the corners of the grains by epitaxial growth.

It is preferred to use the uniform structure type grains having a narrow halogen composition distribution even in the high-silver chloride emulsions having a silver chloride content of at least 90 mol % to prevent sensitivity from being lowered when pressure is applied to photographic materials.

The replenishment rates of processing solutions can be reduced by further increasing the silver chloride content of the silver halide emulsion. In such a case, an almost pure silver chloride emulsion having a silver chloride content of as high as 98 to 99.9 mol % can be preferably used.

The average grain size (the diameter of a circle equivalent to the projected area of the grain is allowed to be a grain size and the average is referred to as average grain size) of the silver halide grains contained in the silver halide emulsion of the present invention is in the range of preferably 0.1 to 2 .mu.m.

The coefficient of variation (a value obtained by dividing the standard deviation of the grain size by the average grain size) of the grain size distribution is preferably not higher than 20%, particularly not higher than 15%. Monodisperse type, with a coefficient of variation being within said range, is preferred. It is also preferred that such monodisperse emulsions are contained in the same layer or are coated in the form of a multi-layer for the purpose of obtaining a wide latitude.

The shape of the silver halide grain to be contained in the photographic emulsion of the present invention may be a regular crystal form such as cube, octahedron or tetradecahedron or an irregular crystal form such as a spherical form or a tabular form or a composite form thereof. If desired, a mixture of grains having these crystal forms may be used. In the present invention, silver halide grains comprising at least 50%, preferably at least 70%, more preferably at least 90% of the grains having the regular crystal form are preferred.

In addition thereto, there can be preferably used emulsions wherein tabular grains having an average aspect ratio (ratio of diameter in terms of a circle/thickness) of not lower than 5, preferably not lower than 8 account for at least 50% (in terms of projected area) of the total amount of grains.

The silver chlorobromide emulsion of the present invention can be prepared by methods described in "Chimie et Phisique Photographique", written by P. Glafkides (published by Paul Montel, 1967), "Photographic Emulsion Chemistry", written by G. F. Duffin (published by Focal Press, 1966) and "Making and Coating Photographic Emulsion", written by V. L. Zelikman et al (published by Focal Press, 1964). Namely, the emulsion of the present invention can be prepared by any of acid process, neutral process and ammonia process. In the preparation thereof, a soluble silver salt can be reacted with a soluble halogen salt by any method of a single jet method, a double jet method and a combination thereof. A reverse mixing method wherein grains are formed in the presence of an excess amount of silver ion, can also be used. As a mode of the double jet method, a controlled double jet method wherein a pAg value in a liquid phase is kept constant, can be used. According to this method, there can be obtained a silver halide emulsion wherein the crystal form of the grain is regular and the grain size is almost uniform.

Various polyvalent metal ion impurities can be introduced into the silver halide emulsion of the present invention during the course of the formation of emulsion grains or during the course of the physical ripening thereof. Examples of compounds used therefor include salts of cadmium, zinc, lead, copper and thallium and salts and complex salts of Group VIII elements such as iron, ruthenium, rhodium, palladium, osmium, iridium and platinum. Among them, Group VIII elements are preferred. The amounts of these compounds to be added widely vary depending on the purpose of use, but are generally in the range of preferably 10.sup.-9 to 10.sup.-2 mol based on the amount of silver halide.

The silver halide emulsions of the present invention are generally subjected to chemical sensitization or spectral sensitization.

Examples of the chemical sensitization include sulfur sensitization (sensitization being conducted typically by adding unstable sulfur compounds), noble metal sensitization such as gold sensitization and reduction sensitization. These sensitization methods may be used either alone or in a combination thereof. Preferred compounds which can be used for the chemical sensitization are described in JP-A-62-215272 (from the lower right column of page 18 of the specification to the upper right column of page 22 thereof).

The spectral sensitization is carried out to impart spectral sensitivity to the desired light wave range of each emulsion. It is preferred that dyes absorbing light in wave range corresponding to the desired spectral sensitivity, that is, spectral sensitizing dyes are added. Examples of the spectral sensitizing dyes include those described in the literature "Heterocyclic Compounds--Cyanine Dyes and Related Compounds", written by F. M. Harmer, published by John Wiley & Sons (New York, London) 1964. Preferred compounds are described in JP-A-62-215272 (from the upper right column of page 22 of the specification to page 38 thereof).

Various compounds or precursors thereof can be added to the silver halide emulsions for use in the present invention for the purpose of preventing fogging from being caused during the course of the preparation of photographic materials or the storage thereof or during the course of photographic processing or for the purpose of stabilizing photographic performance. These compounds and precursors are generally called photographic stabilizers. Preferred examples of these compounds include those described in JP-A-62-215272 (from page 39 of the specification to page 72 thereof).

The emulsions for use in the present invention may be any of a surface latent image type wherein a latent image is predominantly formed on the surface of the grain and an internal latent image type wherein a latent image is predominantly formed in the interior of the grain.

The color photographic material of the present invention generally contain a yellow coupler, a magenta coupler and a cyan coupler, said couplers forming yellow color, magenta color and cyan color, respectively, by the reaction of each of them with the oxidation product of an aromatic amine developing agent.

Preferred examples of the cyan coupler and the magenta coupler which can be used in the present invention include compounds represented by the following formulae (C-I), (C-II), (M-I) and (M-II). ##STR103##

In the formulae (C-I) and (C-II), R.sub.1, R.sub.2 and R.sub.4 each represents a substituted or unsubstituted aliphatic, aromatic or heterocyclic group; R.sub.3, R.sub.5 and R.sub.6 each represents a hydrogen atom, a halogen atom, an aliphatic group, an aromatic group or an acylamino group or R.sub.3 may be a non-metallic atomic group which is combined together with R2 to form a 5-membered or 6-membered nitrogen-containing ring; and Y.sub.1 and Y.sub.2 each represents a hydrogen atom or a group which can be released by the reaction with the oxidation product of a developing agent.

Preferred examples of R.sub.5 in the formula (C-II) are aliphatic groups such as methyl, ethyl, propyl, butyl, pentadecyl, tert-butyl, cyclohexyl, cyclohexylmethyl, phenylthiomethyl, dodecyloxyphenylthiomethyl, butaneamidomethyl and methoxymethyl.

Preferred cyan couplers represented by the formulae (C-I) and (C-II) are the following compounds.

There are preferred the compounds of the formula (C-I) where R.sub.1 is an aryl group or a heterocyclic ring. There are more preferred the compounds where said aryl group is substituted by one or more of a hydrogen atom, an alkyl group, an alkoxy group, an aryloxy group, an acylamino group, an acyl group, a carbamoyl group, a sulfonamido group, a sulfamoyl group, a sulfonyl group, a sulfamido group, a hydroxycarbonyl group and a cyano group.

In the case where R.sub.3 and R.sub.2 are not combined together to form a ring, there are preferred the compounds of the formula (C-I) where R.sub.2 is a substituted or unsubstituted alkyl group or an aryl group, particularly a substituted aryloxy-substituted alkyl group and R.sub.3 is a hydrogen atom.

There are preferred the compounds of the formula (C-II) where R.sub.4 is a substituted or unsubstituted alkyl group or an aryl group, particularly a substituted aryloxy-substituted alkyl group.

There are preferred the compounds of the formula (C-II) where R.sub.5 is an alkyl group having from 2 to 15 carbon atoms or a methyl group having C.sub.1 or higher substituent group. Preferred substituent groups are an arylthio group, an alkylthio group, an acylamino group, an aryloxy group and an alkyloxy group. There are more preferred the compounds of the formula (C-II) where R.sub.5 is an alkyl group having from 2 to 15 carbon atoms, particularly an alkyl group having from 2 to 4 carbon atoms.

There are preferred the compounds of the formula (C-II) where R.sub.6 is a hydrogen atom or a halogen atom, particularly chlorine or fluorine. Preferred examples of Y.sub.1 and Y.sub.2 in the formulae (C-I) and (C-II) are a hydrogen atom, a halogen atom, an alkoxy group, an aryloxy group, an acyloxy group and a sulfonamido group.

In the formula (M-I), R.sub.7 and R.sub.9 each represents an aryl group; R.sub.8 represents a hydrogen atom, an aliphatic or aromatic acyl group or an aliphatic or aromatic sulfonyl group; and Y.sub.3 represents a hydrogen atom or a coupling off group. The aryl group (preferably phenyl group) represented by R.sub.7 and R.sub.9 may have one or more substituent groups. Examples of the substituent groups are those already described above in the definition of the substituent groups for R.sub.1. When two or more substituent groups exist, they may be the same or different groups. R.sub.8 is preferably a hydrogen atom or an aliphatic acyl or a sulfonyl group. A hydrogen atom is particularly preferred. Y.sub.3 is preferably a group which can be released by any of sulfur, oxygen and nitrogen atoms. There is particularly preferred a group which can be released by sulfur atom described in U.S. Pat. No. 4,351,897 and PCT-WO 88/04795.

In the formula (M-II), R.sub.10 represents a hydrogen atom or a substituent group; Y.sub.4 represents a hydrogen atom or a release group, preferably a halogen atom or an arylthio group; and Za, Zb and Zc each represents methine, a substituted methine, .dbd.N-- or --NH-- and one of Za--Zb bond and Zb--Zc bond is a double bond and the other is a single bond. When Zb--Zc bond is a carbon-to-carbon double bond, the bond may be part of an aromatic ring. A dimer or polymer may be formed by R.sub.10 or Y.sub.4. When Za, Zb or Zc is a substituted methine, a dimer or polymer may be formed by the substituted methine.

Among the magenta couplers, the pyrazoloazole couplers represented by the formula (M-II) are preferred, because they are excellent in color reproduction and scarcely causes stain. Further, among these compounds, there are preferred imidazo[1,2-b] pyrazole compounds described in U.S. Pat. No. 4,500,630, because color forming dyes scarcely have yellow side absorption and they are excellent in fastness to light. Pyrazolo[1,5-b][1,2,4]triazole compounds described in U.S. Pat. No. 4,540,654 are particularly preferred.

There are preferred pyrazolotriazole couplers wherein a branched alkyl group is directly attached to the position 2, 3 or 6 of its pyrazolotriazole ring, described in JP-A-61-65245; pyrazoloazole couplers having a sulfonamido group in the molecular structure described in JP-A-61-65246; pyrazoloazole couplers having an alkoxyphenylsulfonamido ballast group described in JP-A-61-147254; and pyrazoloazole couplers having an alkoxy or aryloxy group at the position 6 thereof described in EP-A-226,849 and EP-A-294,785.

Examples of the couplers represented by the formulae (C-I) to (M-II) include the following compounds. ##STR104##

Compound R.sub.10 R.sub.15 Y.sub.4 M-9 CH.sub.3 ##STR105## Cl M-10 " ##STR106## " M-11 (CH.sub.3).sub.3 C ##STR107## ##STR108## M-12 ##STR109## ##STR110## ##STR111## M-13 CH.sub.3 ##STR112## Cl M-14 " ##STR113## " M-15 " ##STR114## " M-16 " ##STR115## " M-17 CH.sub.3 ##STR116## Cl M-18 ##STR117## ##STR118## ##STR119## M-19 CH.sub.3 CH.sub.2 O " " M-20 ##STR120## ##STR121## ##STR122## M-21 ##STR123## ##STR124## Cl M-22 CH.sub.3 ##STR125## Cl M-23 " ##STR126## " M-24 ##STR127## ##STR128## " M-25 ##STR129## ##STR130## " M-26 ##STR131## ##STR132## Cl