Silver halide photographic material - Patent Review 4772542

What is claimed is:

1. A silver halide photographic material having formed on a support at least one unit structure consisting of two or more silver halide emulsion layers which are sensitive to light of substantially the same color but which have different sensitivities, one of said silver halide emulsion layers having a highest sensitivity containing a coupler which forms a mobile dye by coupling reaction with an oxidized product of a color developing agent and said silver halide emulsion layer with said highest sensitivity having in association therewith a non-light-sensitive layer containing substantially non-light-sensitive fine silver halide grains, said non-light-sensitive layer adjoining said silver halide emulsion layer with said highest sensitivity, said silver halide emulsion layer with said highest sensitivity being positioned furthest from said support in said unit.

2. A silver halide photographic material according to claim 1, wherein said coupler is represented by the following formula (I): ##STR8## wherein COUP represents the coupler nucleus which forms a dye; the stabilizing group is a group which is bound to the coupling site on said nucleus and which is split off therefrom upon coupling reaction between said coupler and the oxidized product of a color developing agent, said stabilizing group having a sufficient molecular size and shape to render said coupler nondiffusible; and the adjusting group is a group which is bound to a non-coupling site with respect to said necleus and which has a size and shape sufficient to impart mobility to the dye formed by the coupling reaction between said coupler and said oxidized product.

3. A silver halide photographic material according to claim 2, wherein the adjusting group in said formula (I) is a group having 1 to 20 carbon atoms.

4. A silver halide photographic material according to claim 2, wherein the stabilizing group in said formula (I) is a group having 8 to 32 carbon atoms.

5. A silver halide photographic material according to claim 4, wherein said stabilizing group is an alkyl or phenyl group.

6. A silver halide photographic material according to claim 2, wherein said coupler represented by formula (I) is a coupler represented by the following formula (II): ##STR9## wherein R.sup.1 is an aryl or alkyl group; R.sup.2 is the stabilizing group defined in formula (I); R.sup.3 is the adjusting group defined in formula (I); and R.sup.4 is a hydrogen or halogen atom, an alkyl, alkoxy or sulfamoyl group or the adjusting group defined in formula (I).

7. A silver halide photographic material according to claim 2, wherein said coupler represented by formula (I) is a coupler represented by the following formula (III) cr (IV): ##STR10## wherein R.sup.5 is the stabilizing group defined in formula (I); R.sup.6, R.sup.7 and R.sup.8 each represents a hydrogen or halogen atom, an alkyl, alkoxy or alklamido group or the adjusting group defined in formula (I), provided that one of R.sup.6, R.sup.7, and R.sup.8 is the adjusting group defined in formula (I); R.sup.9 has the same meaning as R.sup.5 ; and R.sup.10 is the adjusting group defined in formula (I).

8. A silver halide photographic material according to claim 2, wherein said coupler represented by formula (I) is a coupler represented by the following formula (V), (VI) or (VII): ##STR11## wherein R.sup.11 is the stabilizing group defined in formula (I); R.sup.12 is the adjusting group defined in formula (I); Ar is a pheny group; R.sup.13 has the same meaning as R.sup.11 ; R.sup.14 and R.sup.15 each is a hydrogen atom, an alkyl, alkoxy, aryl, amino or acylamino group or the adjusting group defined in formula (I), provided that either R.sup.14 or R.sup.15 is the adjusting group defined in Formula (I); R.sup.16 has the same meaning as R.sup.11 ; either R.sup.17 or R.sup.18 is the adjusting group defined in formula (I), the other one being a hydrogen atom or an alkyl, alkoxy, aryl, amino, acylamino or ureido group.

9. A silver halide photographic material according to claim 6, wherein the adjusing group represented by R.sup.3 and R.sup.4 in said formula (II) is a group selected from the group consisting of hydrogen and halogen atoms and carboxy hydroxy, nitro, cyano, alkyl, alkoxy, aryloxy, sulfonamido, acylamino, carbamoyl, sulfamoyl, alkoxycarbonyl, aryloxycarbonyl, acyloxy, sulfonoxy, ureido and alkylsulfonyl groups.

10. A silver halide photographic material according to claim 7, wherein the adjusting group represented by R.sup.6, R.sup.7 and R.sup.8 in said formula (III) is a group selected from the group consisting of hydrogen and halogen atoms and alkyl, alkoxy, acylamino, sulfonamido and ureido groups.

11. A silver halide photographic material according to claim 7, wherein the adjusting group represented by R.sup.10 in said formula (IV) is a carbamoyl group.

12. A silver halide photographic material according to claim 8, wherein the adjusting group represented by R.sup.12 in said formula (V) and by R.sup.17 and R.sup.18 in said formula (VII) is a group selected from the group consisting of alkyl, acylamino, anilino, ureido and pyrolidinyl groups.

13. A silver halide photographic material according to claim 8, wherein the adjusting group represented by R.sup.14 and R.sup.15 in said formula (VI) is a group selected from the group consisting of a halogen atom and alkyl, alkoxy, aryl, acylamino, alkylthio, amino, alkylcarbamoyl and aralkyl groups.

14. A silver halide photographic material according to claim 1, wherein said coupler is a nondiffusible coupler.

15. A silver halide photographic material according claim 1, wherein said coupler is incorporated in the emulsion layer having the highest sensitivity in an amount of 0.01 to 0.2 mol/mol of silver.

16. A silver halide photographic material according to claim 1, wherein said fine silver halide grains have an average grain size of 0.02 to 0.2 .mu..

17. A silver halide photographic material according to claim 1, wherein said fine silver halide grains are incorporated in the non-light sensitive layer in an amount of 0.01 to 1 g/m.sup.2 in terms of silver (Ag).

18. A silver halide photographic material according to claim 1 wherein said unit structure consists of three silver halide emulsion layers.

19. A silver halide photographic material according to claim 1 wherein said silver halide emulsion layers are panchromatically sensitized.

20. A method of forming color negative images by imagewise exposing a silver halide phtographic material and then processing the exposed material with a color developer, said material having formed on a support at least one unit structure comprising two silver halide emulsion layers which are sensitive to light of substantially the same color but which have different sensitivites, one of said silver halide emulsion layers having a highest sensitivity containing a coupler which forms a mobile dye by coupling reaction with an oxidized product of a color developing agent, and said silver halide emulsion layer with the highest sensitivity having in association therewith a non-light-sensitive layer containing substantially non-light-sensitive fine silver halide grains, said non-light-sensitive layer being positioned adjacent to said silver halide emulsion layer having the highest sensitivity in the unit and in a place furthest from said support.

21. A method of forming color negative images according to claim 20, wherein said coupler is represented by formula (II): ##STR12## wherein R.sup.1 is an aryl or alkyl group; R.sup.2 is a stabilizing group which is bound to the coupling site on said nucleus and which is split off therefrom upon coupling reaction between said coupler and the oxidized product of a color developing agent, said stabilizing group having a sufficient molecular size and shape to render said coupler non-diffusible; R.sup.3 is an adjusting group which is bound to a non-coupling site with respect to said nucleous and which has a size and shape sufficient to impart mobility to the dye formed by the coupling reaction between said coupler and said oxidized product; and R.sup.4 is a hydrogen, halogen, alkyl, alkoxy, or sulfamoyl or said adjusting group.

22. A method of forming color negative images according to claim 20, wherein said coupler is represented by formulas (III) or (IV): ##STR13## wherein R.sup.5 is said stabilizing group; R.sup.6, R.sup.7 and R.sup.8 each represents hydrogen, halogen, alkyl, alkoxy, alkylamido or said adjusting group; provided that at least one of R.sup.6, R.sup.7 and R.sup.8 is said adjusting group; R.sup.9 has the same meaning as R.sup.5 ; and R.sup.10 is said adjusting group.

23. A method of forming color negative images according to claim 20, wherein said silver halide emulsion is a core-shell type emulsion.

24. A method of forming color negative images according to claim 20 wherein said unit structure consists of three silver halide emulsion layers.

25. A silver halide photographic material having formed on a support at least one unit structure consisting of two or more silver halide emulsion layers which are sensitive to light of substantially the same color but which have different sensitivities, one of said silver halide emulsion layers having a highest sensitivity containing a coupler which forms a mobile dye by coupling reaction with an oxidized product of a color developing agent and said silver halide emulsion layer with said highest sensitivity having in association therewith a non-light-sensitive layer containing substantially non-light-sensitive fine silver halide grains and being positioned farther away from the support in said unit, said non-light-sensitive layer adjoining said silver halide emulsion layer with said highest sensitivity, said non-light-sensitive layer being positioned furthest from said support in said unit.

Description Submit all comments and votes

FIELD OF THE INVENTION

The present invention relates to a silver halide color photographic material, and, more particularly, to a silver halide color photographic material having high sensitivity and providing an image of good quality (particularly improved granularity).

BACKGROUND OF THE INVENTION

Silver halide color photographic materials, particularly those used in picture taking, are required to have specific properties such as high sensitivity and high quality image, especially good granularity. The demand for meeting these requirements is ever increasing today since the tendency toward using smaller cameras necessitates the reduction in the size of images such as in negative films. While many improvements have been made in technology of manufacturing silver halide color photographic materials and products with improved performance have been developed, most of them are unable to solve the problem of trade-off between the sensitivity and image quality. As is well known in the art, tremendous difficulty is involved in achieving a significant increase in the sensitivity of silver halide photographic materials, and there is no technology available today that is capable of increasing the sensitivity without impairing the resulting image quality (granularity, among other things). A particularly great difficulty is encountered in an attempt at increasing the sensitivity of a lower layer in a multi-layered silver halide color photographic material, i.e., a silver halide light-sensitive layer closer to the support, as well as at improving the quality (e.g. tone gradation) of the image formed in that layer, and no technology proposed to date has been found completely satisfactory. There are several factors that explain this difficulty: (1) "interlayer effect" or delayed diffusion of an aromatic primary amine developing agent into a light-sensitive layer closer to the support of a silver halide multi-layered color photographic material under development; (2) diffusion of a development retarding compound incorporated in that particular light-sensitive layer or in any other layer; (3) optical loss due to a non-sensitive layer or emulsion layer positioned in the upper part of the photographic material during exposure.

Various methods are known for sensitizing silver halide emulsions, and they include: modifying the step of physical ripening by, for example, making coarser silver halide grains; chemical sensitization with noble metal, sulfur, selenium or reduction sensitizers; spectral sensitization; sensitization by addition of fine silver halide grains to a silver halide emulsion; sensitization by addition of a silver halide solvent to the silver halide emulsion; and sensitization using a two-equivalent coupler or any other coupler that is capable of rapid reaction with the oxidized product of a developing agent.

Various techniques have also been proposed for providing an improved image quality. Particularly active efforts are being made to commercialize the method of incorporating in a silver halide color photographic material a compound that releases a development retarding compound during development. Two typical examples of this DIR compound are DIR-couplers (development inhibitor releasing couplers) that not only form a color dye by reaction with the oxidized product of a color developing agent but also release a development inhibitor, and DIR-hydroquinones or DIR-substances that release a development inhibitor but which are substantially incapable of forming a color dye upon reaction with the oxidized product of a color developing agent; these latter compounds form a colorless compound by reaction with the oxidized product of the color developing agent.

The use of these DIR compounds is highly effective for the purpose of providing an image of improved quality, but if they are combined with one of the known sensitizing techniques shown above, two serious defects arise. Firstly, the sensitivity of an emulsion layer containing a DIR compound that releases a development inhibitor imagewise during development is decreased due to the "interimage effect" that is detrimental to the development of that layer. This problem is particularly significant if the diffusibility of the development inhibitor released from the DIR compound (e.g. DIR-hydroquinone, DIR-substance or DIR-coupler) is small. The second problem is the "interimage effect" wherein the development inhibitor released upon development diffuses into an adjacent overlying or underlying emulsion layer, or even into an emulsion layer that is sensitive to light of a different color, and in that layer the inhibitor exhibits its development inhibiting action in accordance with the imagewise distribution specific to the layer where said inhibitor is initially incorporated. This interimage effect becomes significant if the released development inhibitor is a halide ion or organic heterocyclic compound having high diffusibility.

In order to avoid these two deleterious effects, the DIR compounds should be used in limited amounts, but then this makes it impossible to achieve the necessary sensitization by combining a particular DIR compound with one of the known sensitizing techniques; furthermore, the improvement in the image quality is far from being satis- factory.

Methods have been proposed for eliminating the above mentioned defects of using DIR compounds. According to one proposal, a non-light sensitive colloidal layer is placed adjacent to an emulsion layer containing a DIR compound. This adjacent layer contains substantially non-developable or low-sensitivity silver halide grains and is capable of adsorbing a development inhibitor released from the DIR compound. This non-sensitive layer per se is effective in reducing or limiting the adverse effects of the development inhibitor released from each silver halide color emulsion layer, and if this layer is placed adjacent each emulsion layer, the sensitivity of that emulsion layer is not greatly reduced. However, other serious defects occur, such as increased fog and reduced storage stability. These are fatal to the commercial value of the final photographic product.

The long felt need for providing a silver halide photographic material having high sensitivity and good image quality (especially high granularity) is yet to be satisfied.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a silver halide color photographic material having high sensitivity and which forms a dye image having good granularity.

This object of the present invention can be achieved by a silver halide photographic material having at least one silver halide emulsion layer on a support, said silver halide emulsion layer containing a coupler which forms a mobile dye by entering into coupling reaction with the oxidized product of a color developing agent, said silver halide emulsion layer having in association therewith a non-light sensitive layer containing substantially non-light sensitive fine silver halide grains.

DETAILED DESCRIPTION OF THE INVENTION

Photographic sensitivity depends on three factors, i.e., the sensitivity of silver halide grains determined by the efficiency of photochemical reaction, the amount of light received by individual grains, and development efficciency. As already mentioned in connection with the prior art, there is a trade-off between the improvement of photographic sensitivity and that of image quality, particularly granularity. This problem cannot be simply solved by comulative combination of functional compounds. Instead, the present inventors took the approach of studying the behavior of the molecules or ions diffusing in a hydrophilic colloid jelly of a silver halide photographic material which is immersed in a developing solution. Upon development, silver halide generates highly diffusible halide ions (particularly, bromide ions) which retard continuous development of the layer in which such ions have been generated or a layer into which these ions are diffused. As a result of the desensitizing effect of this phenomenon, the color density is reduced (i.e., reduced tone reproduction). Furthermore, the coupler used for the purpose of providing an improved granularity generates a dye which may diffuse either excessively to impair the image acuity or insufficiently to cause poor granularity. In view of these facts, the present inventors studied the mechanism of the diffusion of the molecules or ions of various substances that affect the photographic sensitivity (hereunder simply referred to as sensitivity) and granularity in a hydrophilic colloid jelly of a photographic material. The present invention has been accomplished by controlling the behavior of such molecules or ions diffusing in the jelly and providing a properly adjusted environment for this diffusion.

The silver halide photographic material of the present invention comprises at least one silver halide emulsion layer formed on a support which contains a mobile dye forming coupler and a non-light sensitive layer provided in association with this silver halide emulsion layer and which contains substantially non-light sensitive fine silver halide grains. There is no particular limitation on the number of emulsion layers and non-light sensitive layers to be formed on the support, nor on the order of the arrangement of these layers.

The term "in association" used in this specification means that the two essential layers used in the photographic material of the invention are disposed in such a manner that they interact with each other. A preferred embodiment of the two layers provided in association with each other is such that the non-light sensitive layer containing substantially non-light sensitive fine silver halide grains is disposed adjacent to the emulsion layer containing a mobile dye forming coupler and in a place farther away from the support.

The silver halide emulsion layer according to the present invention may be of a unit structure consisting of two or three emulsion layers which are sensitive to light of substantially the same color but which have different sensitivities. This unit has in association therewith at least one non-light sensitive layer defined above, as well as other photographically functional auxiliary layers. A preferred layer arrangement of the unit of emulsion layers is such that a layer having higher sensitivity is positioned farther away from the support. According to the present invention, the mobile dye forming coupler is preferably incorporated in the emulsion having the highest sensitivity in the unit, with the non-sensitive layer defined above being positioned adjacent to that emulsion layer and in a place farther from the support. The silver halide emulsion layer used in the present invention may consist of several units of emulsion layers, with every two units having sensitivity to light of different colors. In this case, a unit having sensitivity to light of a shorter wavelength is preferably disposed farther from the support.

While various layer arrangements may be employed depending upon the specific object and use of the silver halide photographic material, a typical example is a combination of a unit composed of two blue-sensitive emulsion layers, one having a higher sensitivity than the other, a non-sensitive layer and any other auxiliary layer, a unit consisting of a highly green-sensitive emulsion layer and a highly red-sensitive emulsion layer, and a unit consisting of green- and red-sensitive emulsion layers, both having a lower sensitivity than those making up the second unit.

For the purpose of preventing retarded development in a color photographic material using two or more silver halide emulsion layers having sensitivity to light of different colors, it is preferred that the mobile dye forming coupler according to the present invention is incorporated in at least that emulsion layer which is positioned closest to the support while the non-light sensitive layer defined above is disposed in association with that emulsion layer.

The mobile dye forming coupler according to the present invention is represented by the following formula (I): ##STR1## In formula (I), COUP represents the nucleus of the coupler that forms a dye, and the stabilizing group is one which is bound to the coupling site on the nucleus and which leaves COUP upon coupling reaction between the coupler and the oxidized product of a color developing agent. The stabilizing group has a sufficient molecular size and shape to render the coupler nondiffusible. The adjusting group is bound to a non-coupling site with respect to COUP and has a size and shape sufficient to impart mobility to the dye formed by the coupling reaction between the coupler and the oxidized product of a color developing agent.

The coupler nucleus represented by COUP may be selected from among any compounds that are commonly used in the art to form dyes upon coupling reaction with the oxidized product of a color developing agent. Illustrative yellow dye forming couplers are acyl acetanilides and benzoyl acetanilides. Illustrative magenta dye forming couplers are pyrazolones, pyrazolotriazoles, pyrazolobenzimidazoles and indazolones. Illustrative cyan dye forming couplers are phenols and naphthols.

The stabilizing group in formula (I) has a size and shape sufficient to impart mobility to the coupler. Useful stabilizing groups include alkyl, aryl and heterocyclic moieties having rot less than 8 carbon atoms, preferably 8 to 32 carbon atoms. These stabilizing groups may have substituents that will change the reactivity of the coupler, such as halogen atoms, nitro, cyano, alkoxy, aryloxy, carboxy, alkoxycarbonyl, sulfo, sulfamoyl, carbamoyl, acylamino, diacylamino, ureido, urethane, sulfonamido, hetero ring, arylsulfonyl, alkylsulfonyl, arylthio, alkylthio, alkylamino, hydroxy, alkyl and aryl. These stabilizing groups may have a cross-linking group that binds them to the coupling site on the coupler nucleus. Typical cross-linking groups include --O--, --S--, --N.dbd.N-- and ##STR2## (wherein Z is an atomic group necessary to form a 5- to 7-membered hetero ring). Preferred stabilizing groups with such cross-linking groups include alkoxy, aryloxy, heterocyclic oxy, alkylthio, arylthio, heterocyclic thio and nitrogen-containing hetero rings having 8 to 32 carbon atoms.

The stabilizing group preferably has the additional ability to release a photographically useful group a predetermined time after it leaves the coupler upon its coupling reaction with the oxidized product of a color developing agent. The stabilizing group may render the coupler nondiffusible by forming a polymer which binds to the coupling site on the coupler nucleus with the aid of a suitable cross-linking group described above.

The adjusting group in formula (I) has a sufficient size and shape to impart mobility to the dye produced by coupling reaction with a color developing agent. For a given adjusting group, the mobility of the dye formed varies with the type of the coupler nucleus to which the adjusting group is bonded, the type of substituents introduced into the coupler nucleus, and the type of color developing agent that couples with the coupler to form the dye. Any adjusting group may be used so long as it imparts the desired mobility to the dye. Preferred adjusting groups include an alkyl group, a cyclocyclic alkyl group, aryl groups having 6 to 20 carbon atoms and a heterocyclic group. These groups may be substituted by groups that affect the spectral characteristics and mobility of the dye. The adjusting group may contain a basic ionizable group such as hydroxy, carboxy, sulfo or aminosulfonyl, or an ionizable salt thereof, which imparts mobility to otherwise nondiffusible dyes. These basic ionizable groups may be present in the form of their precursors, which, upon hydrolysis or intramolecular nucleophilic substitution reaction during development, forms a basic ionizable group that imparts mobility to otherwise nondiffusible dyes.

These adjusting groups may have a cross-linking group that assists its binding to the coupler nucleus. Illustrative cross-linking groups used for this purpose include --O--, --S--, --CO--, --COO--, --NR--, --CONR--, --NRCO--, --SO.sub.2 NR--, --NRSO.sub.2 --, and --NRCONR-- (wherein R is a hydrogen atom, an alkyl group or an aryl group).

Preferred couplers capable of producing yellow mobile dyes are represented by the following formula (II): ##STR3## wherein R.sup.1 is an aryl group (e.g. phenyl) or an alkyl group (e.g. tertiary alkyl group such as t-butyl group); R.sup.2 is the stabilizing group defined above; R.sup.3 is the adjusting group defined in formula (I) including, for example, hydrogen and halogen atoms and calboxy hydroxy, nitro, cyano, alkyl, alkoxy, aryloxy, sulfonamido, acylamino, carbamoyl, sulfamoyl, alkoxycarbonyl, aryloxycarbonyl, acyloxy, sulfonoxy, ureido and alkylsulfonyl groups; and R.sup.4 is a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a sulfamoyl group or the adjusting group defined in formula (I) as exemplified in R.sup.3 above. Particularly preferred examples of the stabilizing group bound to these couplers by a cross-linking group are aryloxy, heterocyclic oxy and nitrogen-containing hetero rings.

Preferred examples of the coupler that forms a mobile cyan dye are represented by the following formulas (III) and (IV): ##STR4## wherein R.sup.5 has the same meaning as R.sup.2 in formula (II); one of R.sup.6, R.sup.7 and R.sup.8 is the adjusting group defined in formula (I) including, for example, hydrogen and halogen atoms and alkyl, alkoxy, acylamino, sulfonamido and ureido groups, and the other two groups which may be the same or different represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or an alkylamido group; R.sup.9 has the same meaning as R.sup.5 ; and R.sup.10 is the adjusting group, for example, a carbamoyl group. Particularly preferred examples of the stabilizing group bonded to the coupler nucleus by a cross-linking group include alkyloxy, aryloxy, heterocyclic oxy and arylazo.

Preferred couplers that form mobile magenta dyes are represented by the following formulas (V), (VI) and (VII): ##STR5## wherein R.sup.11 has the same meaning as R.sup.5 in formula (III); R.sup.12 is the adjusting group including, for example, alkyl, acylamino, anilino, ureido and pyrolidynyl groups; Ar is a phenyl group which may have a substituent selected from among a halogen atom, an alkyl group, an alkoxy group, an amino group and a sulfo group, said phenyl group optionally having the adjusting group defined above; R.sup.13 has the same meaning as R.sup.11 ; one of R.sup.14 and R.sup.15 is the adjusting group including, for example, a halogen atom and alkyl, alkoxy, aryl, acylamino, alkylthio, amino, alkylcarbamoyl and aralkyl groups, the other one being a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an amino group or an acylamino group; R.sup.16 has the same meaning as R.sup.11 ; one of R.sup.17 and R.sup.18 is the adjusting group as exemplified R.sup.12 above, and the other is a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an amino group, an acylamino group or a ureido group.

Particularly preferred examples of the stabilizing group that is bonded to the coupler nucleus by a crosslinking group are aryloxy, alkylthio, arylthio, heterocyclic thio and arylazo.

The non-diffusible couplers shown above which form a mobile dye upon coupling with the oxidized product of a color developing agent are preferably incorporated in at least the emulsion layer having the highest sensitivity in a unit of emulsion layers which are sensitive to light of substantially the same color but which have different sensitivities. For example, if the unit consists of a bottommost emulsion layer of low sensitivity, an overlying emulsion layer of medium sensitivity, and a topmost layer of high sensitivity, the non-diffusible coupler is preferably incorporated in at least the emulsion layer of high sensitivity.

These couplers are preferably incorporated in the emulsion layer of high sensitivity in an amount of 0.01-0.03 mol/mol of silver, and in an emulsion layer of low sensitivity in an amount of 0.05-0.15 mol/mol of silver. The couplers may be used in combination with a suitable DIR compound which is preferably used in an amount of 0.0005-0.08 mol/mol of silver.

Typical examples of the non-diffusible coupler shown above which forms a mobile dye upon coupling reaction with the oxidized product of a color developing agent are listed below, but it should be understood that the scope of the present invention is by no means limited to these examples. ##STR6##

The silver halide emulsion layers according to the present invention may contain photographic couplers other than the mobile dye forming couplers shown above. Preferred photographic cyan couplers are phenolic and naphtholic compounds, which may be selected from among those shown in U.S. Pat. Nos. 2,369,929, 2,434,272, 2,474,293, 2,895,826, 3,253,924, 3,034,892, 3,311,476, 3,386,301, 3,419,390, 3,458,315, 3,476,563 and 3,591,383. These references also list the methods of synthesis of the compounds shown above.

Illustrative photographic magenta couplers include pyrazolones, pyrazolotriazoles, pyrazolinobenzimidazoles and indazolones. Pyrazolone magenta couplers that may be advantageously used in the present invention are shown in U.S. Pat. Nos. 2,600,788, 3,062,653, 3,127,269, 3,311,476, 3,419,391, 3,519,429, 3,558,318, 3,684,514, and 3,888,680; Japanese Patent Public Disclosure Nos. 29639/1974, 111631/1974, 129538/1974, and 13041/1975, Japanese Patent Publication Nos. 10491/1979, 47167/1978 and 30615/1980. Suitable pyrazolotriazole magenta couplers are shown in U.S. Pat. No. 1,247,493 and Belgian Pat. No. 792,525. Useful pyrazolinobenzimidazole magenta couplers are listed in U.S. Pat. No. 3,061,432, German Pat. No. 2,156,111 and Japanese Patent Publication No. 60479/1971. Advantageous indazolone magenta couplers are recited in Belgian Pat. No. 769,116.

Known open-chain ketomethylene compounds may be used as photographic yellow couplers in the present invention, and typical examples are commonly used benzoylacetanilide yellow couplers and pivaloyl yellow couplers. Other usable couplers are two-equivalent yellow couplers wherein the carbon atom at coupling site is substituted by a group that are capable of leaving the coupler upon coupling reaction with the oxidized product of a color developing agent. For more details of these yellow couplers and methods of their synthesis, see U.S. Pat. Nos. 2,875,057, 3,265,506, 3,664,841, 3,408,194, 3,447,928, 3,277,155, and 3,415,652; Japanese Patent Publication No. 13576/1974; Japanese Patent Public Disclosure Nos. 29432/1973, 66834/1973, 10736/1974, 122335/1974, 28834/1975 and 132926/1975.

The non-diffusible couplers shown above may be dispersed by various methods such as dispersion in aqueous alkali solutions, solids, latices and in oil-in-water type emulsions. A suitable method should be selected depending upon the chemical structure of the specific coupler.

The non-sensitive layer according to the present invention which contains substantially non-light sensitive fine silver halide grains includes one or more hydrophilic colloidal layers, and at least one of these hydrophilic colloidal layers has dispersed therein substantially non-sensitive silver halide grains.

The non-sensitive fine silver halide grains may be of any type that is substantially non-light sensitive or which is substantially insensitive to a developing solution. Preferred grains are those which are substantially incapable of development and dissolution in a developer. As for their average size, grains not larger than 0.3 .mu.m are preferred, and in order to prevent decreased acuity due to light scattering, the range of 0.02 to 0.2 .mu.m is more preferred. The grain size distribution may be wide or narrow, but a narrow distribution is preferred.

The substantially non-sensitive fine silver halide grains may have any composition such as silver chloride, silver bromide, silver iodide, silver iodobromide, silver chlorobromide, or silver chloroiodobromide. Two or more halide compositions may be used in combination. From a solubility viewpoint, silver halide containing silver bromide is preferred, and silver iodobromide containing less than 10 mol % of silver iodide is particularly preferred. The non-sensitive fine silver halide grains used in the present invention may be physically ripened by rhodanide ions, cyano ions or thiocyanate ions, or etched with a suitable silver halide solvent. These silver halide grains may be prepared by the neutral method, half ammoniacal method or ammoniacal method. The double-jet method or conversion method may be employed depending on the need. Silver halide in the non-sensitive layer is generally deposited in an amount of 0.01-1 g/m.sup.2 in terms of silver (Ag), preferably in an amount of 0.1-0.5 g/m.sup.2. The non-sensitive layer may contain various additives such as a matting agent (e.g. colloidal silica or polymethyl methacrylate), a high-boiling solvent (e.g. tricresyl phosphate or dioctyl phthalate), a UV absorber, an antioxidant, an oleophilic component (e.g. hydroquinone derivative), a coating aid (e.g. surfactant) and gelatin hardener.

Gelatin is a typical binder suitable for use in the non-sensitive layer. Part or all of the gelatin may be replaced by colloidal albumin, agar, gum arabic, alginic acid, or a cellulose derivative such as hydrolyzed cellulose acetate, carboxymethyl cellulose, hydroxyethyl cellulose, or methyl cellulose. Synthetic binders may also be used, and suitable examples are poly (vinyl alcohol), partially saponified poly(vinyl alcohol), polyacrylamide, poly-N,N-dimethylacrylamide, poly-N-vinylpyrrolidone; water-soluble polymers as shown in U.S. Pat. Nos. 3,847,620, 3,655,389, 3,341,332, 3,615,424 and 3,860,428; gelatin derivatives such as phenylcarbamylated gelatin, acylated gelatin and phthalated gelatin of the type shown in U.S. Pat. Nos. 2,614,928 and 2,525,753; as well as copolymers of the type shown in U.S. Pat. Nos. 2,548,520 and 2,831,767 which have grafted to gelatin a monomer having a polymerizable ethylene group such as acrylic acid (or its ester), methacrylic acid (or its ester) or acrylonitrile.

Any of the common silver halide emulsions may be used in the photographic material of the present invention, and they may comprise individual crystals of silver chloride, silver bromide, silver iodobromide, silver chlorobromide, silver chloroiodide o