EP0487228A1

EP0487228A1 - Light-sensitive silver halide photographic material

Info

Publication number: EP0487228A1
Application number: EP91310310A
Authority: EP
Inventors: Yutaka Konica Corporation Nakamura; Masanobu Konica Corporation Miuoshi
Original assignee: Konica Minolta Inc
Current assignee: Konica Minolta Inc
Priority date: 1990-11-13
Filing date: 1991-11-07
Publication date: 1992-05-27
Also published as: JPH04177339A

Abstract

Disclosed is a light-sensitive silver halide photographic material having at least one silver halide emulsion layer on a support, characterized in that at least one of the above silver halide emulsion layers contains a coupler represented by the following formula (M-I), a silver halide grain contained in said silver halide emulsion layer is a mixture of at least two kinds of silver halide emulsions different in sensitivity, and the illuminance dependency of sensitivity of the silver halide emulsion having lower sensitivity is smaller than the illuminance dependency of sensitivity of the silver halide emulsion having higher sensitivity

wherein Z represents a group of non-metallic atoms necessary for forming a nigrogen-containing heterocyclic ring and the ring formed by said Z may have a substituent; X represents hydrogen atom or an eliminatable group by reaction with an oxidized product of a color developing agent; and R represents hydrogen atom or a substituent.

Description

BACKGROUND OF THE INVENTION

This invention relates to a light-sensitive silver halide photographic material (hereinafter called to "a light-sensitive material"), more particularly to a light-sensitive material which is improved in gradation fluctuation caused by variation of exposure illuminance and therefore can give high quality photographs excellent in color reproducibility easily and stably.
There has been well known in the art, as one of the characteristics of a light-sensitive material, a phenomenon that difference in photographic characteristics such as sensitivity is caused between irradiation with high illuminance for a short time and irradiation with low illuminance for a long time even if the same dose of light is irradiated, and this phenomenon is called "reciprocity law failure".
In a system for practical use, a countermeasure of changing exposure dose in proportion to previously estimated change in sensitivity against change in sensitivity caused by different illuminance has been taken, and therefore the above phenomenon is not a serious obstacle in practical use.
However, when gradation fluctuation due to exposure illuminance (hereinafter called "illuminance dependency of gradation") is remarkable, the above phenomenon becomes a fetal defect in quality of a light-sensitive material. Light-sensitive materials have different desired gradations depending on the purpose of use and are designed so as to control gradation, respectively. When these light-sensitive materials are exposed actually, exposure illuminance is changed as a matter of course due to exposure conditions such as brightness of a photographic object in a light-sensitive material for photography and difference in image density caused by excessive or insufficient exposure of an original film in a light-sensitive material for print.
In a light-sensitive material having large illuminance dependency of gradation, an actual gradation is outside an allowable range of designed target gradation due to the degree of exposure illuminance.
For this reason, depending on a scene, contrast becomes too high, whereby a photograph lacks depiction at low density and high density portions, or contrast becomes too low, whereby a photograph lacks sharpness and clearness. Also in the case of a color photograph, when gradation balance between the respective light-sensitive layers is lost, color of a print is changed to become worse. In either case, quality as a light-sensitive material is impaired remarkably.
Further, in the case of a light-sensitive material for print, there are various printing sizes, and even those generally used include a small size called E size to a whole sheet size. Further, depending on the use, a print having a size exceeding 2-fold whole sheet is sometimes prepared.
In general, users firstly make prints some scenes in a small size and then choose preferred scenes among them to order enlargement of them to a large size in many cases. At this time, the same original film is used both in printing in a small size and printing in a large size, and it is difficult to increase light source intensity to a great extent, so that lowering in exposure illuminance to a light-sensitive material for print cannot be prevented when the original film is enlarged to obtain a large sized print. As a result, when illuminance dependency of gradation is large, even if preferred image quality can be obtained in a small print, image quality is lowered in a large print, which is not satisfactory to users.
As disclosed above, since an exposure device has been improved in order to cope with change in sensitivity due to exposure illuminance, such a change is not a serious problem in practical use. However, it is difficult to cope with change in gradation by improving instruments such as an exposure device. Thus, decrease in illuminance dependency of gradation in a light-sensitive material has been demanded.
Many techniques for improving reciprocity law failure property described above of a light-sensitive material have been known.
For example, in Japanese Provisional Patent Publications No. 47941/1986, No. 23146/1986, No. 97648/1986, No. 112142/1986, No. 7042/1987 and No. 316039/1988, U.S. Patent No. 4,269,927, and Japanese Provisional Patent Publications No. 183647/1989 and No. 186655/1989, there have been disclosed techniques for improving reciprocity law failure property by doping Ir, Cd, Pb, Zn, Fe and Rh. However, their effects are insufficient, and undesired changes in photographic characteristics such as lowering in sensitivity, increase in fog and remarkable gradation fluctuation including high contrast or low contrast are caused frequently, whereby the effects obtained have been limited.
Also, in Japanese Provisional Patent Publications No. 212932/1988, No. 304253/1988, No. 121847/1989, No. 121846/1989 and No. 167752/1989, there have been disclosed improved techniques by a silver halide grain formation method and a sensitization method, but their effects are also insufficient.
Further, a technique for controlling gradation in which a mixture of silver halide grains having the same color sensitivity but different in sensitivity is used has been well known in this field of the art. For example, in Japanese Provisional Patent Publications No. 101542/1989, No. 148049/1984 and No. 71838/1988, there have been disclosed techniques of using a mixture of silver halide emulsions which are made different in sensitivity by changing a grain size, a crystal habit or a composition of a silver halide grain, but there is no description suggesting improvement of reciprocity law failure.
In Japanese Provisional Patent Publication No. 192942/1982, there has been disclosed a technique of using a mixture of a silver halide grain containing Ir and a silver halide grain not containing Ir. However, there is no description about the effect on improvement of reciprocity law failure property, and further, there is rather a description that "when two or more kinds of silver halide grains are used in combination, characteristics, particularly contrast and gradation from a low density portion to a high density portion are changed in proportion to change in exposure time, whereby uniform finish cannot be obtained". Thus, not only the effect of the present invention is not suggested, but also the effect of the present invention would not be unexpected.
In Japanese Provisional Patent Publication No. 131544/1989, there has been disclosed a technique in which silver halide emulsions different in a metal-doped amount are mixed and chemical sensitization thereof is carried out, but there is no description about improvement of reciprocity law failure property and also no description suggesting the present invention.
In Japanese Provisional Patent Publications No. 71839/1988, No. 5234/1987 and No. 172348/1987, there have been disclosed examples of using a mixture of emulsions doped with iridium. However, there is no description about reciprocity law failure, and since the conditions are outside the preferred conditions defined in the present invention, the above patent publications do not suggest the present invention.

SUMMARY OF THE INVENTION

A technique which has not been known at all in the prior art as described above, that is, the present inventors have found the fact that even when silver halide emulsions each having large illuminance dependency of gradation are used, if specific conditions are satisfied, a light-sensitive material having excellent reciprocity law failure property and also having excellent sensitivity, gradation, fog resistance and color reproducibility can be obtained by using a mixture of the emulsions in combination with a pyrazoloazole type magenta coupler to accomplish the present invention.
An object of the present invention is to provide a light-sensitive material having extremely small exposure illuminance dependency of gradation by introducing a novel technique for improving reciprocity law failure property.
Another object of the present invention is to provide a light-sensitive material having high sensitivity, excellent in gradation and color reproducibility and also excellent in reciprocity law property.
The objects of the present invention can be accomplished by a light-sensitive silver halide photographic material having at least one silver halide emulsion layer on a support, characterized in that at least one of the above silver halide emulsion layers contains a coupler represented by the following formula (M-I), a silver halide grain contained in said silver halide emulsion layer is a mixture of at least two kinds of silver halide emulsions different in sensitivity, and the illuminance dependency of sensitivity of the silver halide emulsion having lower sensitivity is smaller than the illuminance dependency of sensitivity of the silver halide emulsion having higher sensitivity

wherein Z represents a group of non-metallic atoms necessary for forming a nigrogen-containing heterocyclic ring and the ring formed by said Z may have a substituent; X represents hydrogen atom or a eliminatable group by reaction with an oxidized product of a color developing agent; and R represents hydrogen atom or a substituent.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, the present invention is explained in detail.
First, the magenta coupler represented by the formula (M-I) to be used in the present invention is described.
In the formula (M-I), the substituent represented by R is not particularly limited, but may specifically include each group of alkyl, aryl, anilino, acylamino, sulfonamide, alkylthio, arylthio, alkenyl and cycloalkyl. In addition, there may be mentioned a halogen atom; each group of cycloalkenyl, alkynyl, heterocyclic ring, sulfonyl, sulfinyl, phosphonyl, acyl, carbamoyl, sulfamoyl, cyano, alkoxy, aryloxy, heterocyclicoxy, siloxy, acyloxy, carbamoyloxy, amino, alkylamino, imido, ureido, sulfamoylamino, alkoxycarbonylamino, aryloxycarbonylamino, alkoxycarbonyl, aryloxycarbonyl and heterocyclicthio; a spiro compound residue; and a bridged hydrocarbon compound residue.
The alkyl group represented by R preferably have 1 to 32 carbon atoms, and may be straight or branched.
The aryl group represented by R is preferably phenyl group.
The acylamino group represented by R may include alkylcarbonylamino group and arylcarbonylamino group.
The sulfonamide group represented by R may include alkylsulfonylamino group and arylsulfonylamino group.
As an alkyl component or an aryl component in the alkylthio group or arylthio group represented by R, there may be mentioned the alkyl group or aryl group represented by the above R.
The alkenyl group represented by R preferably have 2 to 32 carbon atoms, and the cycloalkyl group preferably have 3 to 12, particularly preferably 5 to 7 carbon atoms. The alkenyl group may be straight or branched.
The cycloalkenyl group represented by R preferably have 3 to 12, particularly preferably 5 to 7 carbon atoms.
The sulfonyl group represented by R may include an alkylsulfonyl group and an arylsulfonyl group; the sulfinyl group may include an alkylsulfinyl group and an arylsulfinyl group;
the phosphonyl group may include an alkylphosphonyl group, an alkoxyphosphonyl group, an aryloxyphosphonyl group and an arylphosphonyl group;
the acyl group may include an alkylcarbonyl group and an arylcarbonyl group;
the carbamoyl group may include an alkylcarbamoyl group and an arylcarbamoyl group;
the sulfamoyl group may include an alkylsulfamoyl group and an arylsulfamoyl group;
the acyloxy group may include an alkylcarbonyloxy group and an arylcarbonyloxy group;
the carbamoyloxy group may include an alkylcarbamoyloxy group and an arylcarbamoyloxy group;
the ureido group may include an alkylureido group and an arylureido group;
the sulfamoylamino group may include an alkylsulfamoylamino group and an arylsulfamoylamino group;
the heterocyclic group is preferably 5- to 7-membered, specifically 2-furyl group, 2-thienyl group, 2-pyrimidinyl group or 2-benzothiazolyl group;
the heterocyclicoxy group preferably have a 5- to 7-membered heterocyclic ring, and may include, for example, 3,4,5,6-tetrahydropyranyl-2-oxy group and 1-phenyltetrazol-5-oxy group;
the heterocyclicthio group is preferably a 5- to 7-membered heterocyclicthio group, for example, 2-pyridylthio group, 2-benzothiazolylthio group and 2,4-diphenoxy-1,3,5-triazol-6-thio group;
the siloxy group may include trimethylsiloxy group,
triethylsiloxy group and dimethylbutylsiloxy group;
the imido group may include succinimido group, 3-heptadecyl succinimido group, phthalimido group and glutarimido group;
the spiro compound residue may include spiro[3.3]heptan-1-yl; and
the bridged hydrocarbon compound residue may include bicyclo[2.2.1]heptan-1-yl, tricyclo[3.3.1.1^3.7]decan-1-yl and 7,7-dimethyl-bicyclo[2.2.1]heptan-1-yl.
As the eliminatable group by a reaction with an oxidized product of a color developing agent represented by X, there may be mentioned, for example, a halogen atom (chlorine atom, bromine atom and fluorine atom) and each group of alkoxy, aryloxy, heterocyclicoxy, acyloxy, sulfonyloxy, alkoxycarbonyloxy, aryloxycarbonyl, alkyloxalyloxy, alkoxyoxalyloxy, alkylthio, arylthio, heterocyclicthio, alkyloxythiocarbonylthio, acylamino, sulfonamido, nitrogen-containing heterocyclic ring bonded by N atom, alkyloxycarbonylamino, aryloxycarbonylamino, carboxyl and

where R₁′ has the same meaning as those of the above R; Z′ has the same meaning as those of the above Z; R₂′ and R₃′ each represent hydrogen atom, an aryl group, an alkyl group or a heterocyclic group,
preferably a halogen atom, particularly preferably chlorine atom. As the nitrogen-containing heterocyclic ring formed by Z or Z′, there may be mentioned a pyrazole ring, an imidazole ring, a triazole ring and a tetrazole ring, and as the substituent which may be possessed by said ring, there may be mentioned those as described for the above R.
The coupler represented by the formula (M-I) is more specifically represented by, for example, the following formulae (M-II) to (M-VII).
In the above formulae (M-II) to (M-VII), R₁ to R₈ and X each have the same meanings as those of the above R and X.
Among the couplers represented by the formula (M-I), a coupler represented by the following formula (M-VIII) is preferred.

wherein R₁, X and Z₁ each have the same meanings as those of R, X and Z in the formula (M-I).
Among the magenta couplers represented by the formulae (M-II) to (M-VII), the magenta coupler represented by the formula (M-II) is particularly preferred.
As the above substituents R and R₁ on a heterocyclic ring, the substituent represented by the following formula (M-IX) is most preferred.
wherein R₉, R₁₀ and R₁₁ each have the same meaning as those of the above R.
Further, two of the above R₉, R₁₀ and R₁₁, for example, R₉ and R₁₀ may be bonded to form a saturated or unsaturated ring (e.g. cycloalkane, cycloalkene and heterocyclic ring), and also R₁₁ may be bonded to said ring to constitute a bridged hydrocarbon compound residue.
In the formula (M-IX), preferred are (i) a case where at least two of R₉ to R₁₁ are alkyl groups and (ii) a case where one of R₉ to R₁₁, for example, R₁₁ is hydrogen atom and the other two of R₉ and R₁₀ are bonded to form cycloalkyl together with a root carbon atom.
Further, in the case of (i), a case where two of R₉ to R₁₁ are alkyl groups and another one is hydrogen atom or an alkyl group is preferred.
As the substituent which may be possessed by the ring formed by Z in the formula (M-I) or the ring formed by Z₁ in the formula (M-VIII) and R₂ to R₈ in the formulae (M-II) to (M-VI), those represented by the following formula (M-X) are preferred.

- R¹ - SO₂ - R² (M-X)

wherein R¹ represents an alkylene group; and R² represents an alkyl group, a cycloalkyl group or an aryl group.
The alkylene group represented by R¹ preferably have 2 or more, more preferably 3 to 6 carbon atoms in a straight portion, and may be either straight or branched.
The cycloalkyl group represented by R² is preferbly 5- to 6-membered.
In the following, representative specific examples of the compound according to the present invention are shown.
In addition to the above representative specific examples of the compound according to the present invention, as a specific example of the compound according to the present invention, there may be mentioned Compounds No. 1 to No. 4, No. 6, No. 8 to No. 17, No. 19 to No. 24, No. 26 to No. 43, No. 45 to No. 59, No. 61 to No. 104, No. 106 to No. 121, No. 123 to No. 162 and No. 164 to No. 223 among the compounds disclosed on page 18 to page 32 of Japanese Provisional Patent Publication No. 166339/1987.
The above couplers can be synthesized by referring to Journal of the Chemical Society, Perkin I (1977), pp. 2047 to 2052, U.S. Patent No. 3,725,067, Japanese Provisional Patent Publications No. 99437/1984, No. 42045/1983, No. 162548/1984, No. 171956/1984, No. 33552/1985, No. 43659/1985, No. 172982/1985, No. 190779/1985, No. 209457/1987 and No. 307453/1988.
The coupler represented by the formula (M-I) may be used generally in an amount of 1 x 10⁻³ mole to 1 mole, preferably in the range of 1 x 10⁻² mole to 8 x 10⁻¹ mole per mole of silver halide. Further, said coupler may be used in combination with other kinds of magenta couplers
Next, the silver halide emulsion layer according to the present invention is described.
In the present invention, the silver halide grain to be contained in the silver halide emulsion layer containing the pyrazoloazole type magenta coupler represented by the formula (M-I) is a mixture of at least two kinds of silver halide emulsions having substantially the same color sensitivity (preferably green sensitivity) and also different in sensitivity.
In this case, in at least one combination of silver halide emulsions to be mixed, a relationship that the illuminance dependency of sensitivity of the silver halide emulsion having lower sensitivity is smaller than the illuminance dependency of sensitivity of the silver halide emulsion having higher sensitivity should be satisfied. Here, the illuminance dependency of sensitivity is represented by variation width of sensitivity when exposure time is changed from 0.02 second to 10 seconds.
The above sensitivity is represented by a reciprocal of exposure dose necessary for obtaining a reflection density of 0.8, and evaluated with its relative value. The illuminance dependency is examined by an illuminance dependency of sensitivity (ΔS) after the respective samples are subjected to wedge exposure for an exposure time of 0.02 second (high illuminance condition) and for an exposure time of 10 seconds (low illuminance condition) so that the same exposure dose is irradiated, respectively.
The ΔS is a ratio of sensitivity obtained by exposure under high illuminance condition to sensitivity obtained by exposure under low illuminance condition, and represented by the following formula. As the ΔS value is smaller, a silver halide photographic material has smaller illuminance dependency of sensitivity. $Illuminance dependency of sensitivity (ΔS) = \frac{Sensitivity obtained by exposure under high illuminance condition}{Sensitivity obtained by exposure under low illuminance condition}$
In the present invention, a method for making the illuminance dependency of sensitivity of the silver halide emulsion having lower sensitivity smaller than the illuminance dependency of sensitivity of the silver halide emulsion having higher sensitivity is not particularly limited. For example, when a water-soluble iridium comopund which changes conditions of chemical sensitization is added at the time of forming a silver halide grain, the amount to be added may be changed.
At least a part of means for controlling illuminance dependency of sensitivity is preferably carried out by controlling the amount of a water-soluble iridium compound added to at the time of forming or growing a silver halide grain. At this time, the amount of the water-soluble iridium compound to be added is represented by an average amount added per grain of silver halide, and it is preferred that the average amount of the water-soluble iridium compound added per grain of the silver halide emulsion having lower sensitivity is larger than that of the silver halide emulsion having higher sensitivity.
Here, the average amount added per grain of silver halide (Ir)_av is represented by the following formula.

(Ir)_av =: (Ir)/N
(Ir)_av:: Average amount of water-soluble iridium compound added per grain
(Ir):: Total amount of water-soluble iridium compound added
N:: Number of silver halide grain

When an iridium compound is used as a means for controlling illuminance dependency of sensitivity, the water-soluble iridium compound may be used or may not be used in the silver halide emulsion having higher sensitivity, but the average amount added per grain of silver halide is preferably smaller than that of the emulsion having lower sensitivity.
The water-soluble iridium compound may be added in an amount within the range satisfying the above relationship. The amount is preferably in the range of 2 x 10⁻²³ to 5 x 10⁻¹⁶ mole/grain in the emulsion having lower sensitivity and 2 x 10⁻²⁴ to 2 x 10⁻¹⁸ mole/grain in the emulsion having higher sensitivity, more preferably in the range of 2 x 10⁻²³ to 5 x 10⁻¹⁸ mole/grain in the emulsion having lower sensitivity and 2 x 10⁻²⁴ to 2 x 10⁻²⁰ mole/grain in the emulsion having higher sensitivity.
The water-soluble iridium compound to be used in the present invention is not particularly limited, but as the compound which can be preferably used industrially from the standpoints of stability, safety and economy thereof, there may be mentioned an iridium (III) halide compound, an iridium (IV) halide compound and an iridium complex salt having halogen, amines or oxalate as a ligand.
In the following, examples of the water-soluble iridium compound are described, but the present invention is not limited to these.
Iridium trichloride, iridium tribromide, potassium hexachloroiridium (III), ammonium iridium (III) sulfate, potassium iridium (III) disulfate, tripotassium iridium (III) trisulfate, iridium (III) sulfate, iridium (III) trioxalate, iridium tetrachloride, iridium tetrabromide, potassium hexachloroiridium (IV), ammonium hexachloroiridium (IV), potassium iridate (IV) and iridium (IV) trioxalate.
In the present invention, any desired one may be selected from these compounds, and these compounds may be used in combination, if necessary.
These iridium compounds are used by dissolving them in water or a solvent which is miscible with water. There may be used a method frequently used for stabilizing a solution of an iridium compound, that is, a method in which a hydrogen halide (e.g. hydrochloric acid and bromic acid) or an alkali halide (e.g. potassium chloride, sodium chloride and potassium bromide) is added.
The method of adding the water-soluble iridium compound is not particularly limited, but there may be mentioned, for example, a method in which the iridium compound is previously added in a mother liquor before formation of a nucleus, a method in which the compound is added instantaneously during growth of silver halide, a method in which the compound is added to a halide solution and a method in which the compound is added after completion of growth and immediately after physical ripening. The method in which the compound is added to a halide solution is preferred. Further, the iridium compound may be added dividedly at different stages. The iridium compound to be added may be a solution of a mixture of two or more different iridium compounds. Also, solutions of two or more different iridium compounds may be added at different stages, respectively.
The halide composition of the silver halide grain to be used in the silver halide emulsion layer according to the present invention is preferably silver chloride or silver chlorobromide substantially containing no silver iodide. Here, "substantially containing no silver iodide" means an amount of silver iodide contained being 0.1 mole % or less The composition is preferably silver chloride or silver chlorobromide comprising 90 mole % or more of silver chloride composition, more preferably silver chloride or silver chlorobromide comprising 95 mole % or more of silver chloride composition.
The silver halide grain in the silver halide emulsion layer according to the present invention may have any desired shape. One preferred example is a cube having a (100) face as a crystal surface. Also, there may be used grains having octahedral, tetradecahedral and dodecahedral shapes prepared according to the methods disclosed in U.S. Patents No. 4,183,756 and No. 4,225,666, Japanese Provisional Patent Publication No. 26589/1980, Japanese Patent Publication No. 42737/1980 and The Journal of Photographic Science, 21, 39 (1973). Further, a grain having a twin or a grain having an irregular shape may be also used.
The grain size of the silver halide grain to be used in the silver halide emulsion layer according to the present invention is not particularly limited, but the average grain size of the silver halide grain (hereinafter called "Grain A") contained in the silver halide emulsion having lower sensitivity (silver halide emulsion having the lowest sensitivity when three or more kinds of silver halide emulsions having different sensitivities are mixed) is suitably in the range of 0.2 to 1.6 µm. The average grain size of the silver halide grain (hereinafter called "Grain B") contained in the silver halide emulsion having higher sensitivity (silver halide emulsion having the highest sensitivity when three or more kinds of silver halide emulsions having different sensitivities are mixed) is suitably in the range of 0.3 to 1.7 µm.
The above grain size is represented by a diameter of the grain when the silver halide grain is spherical or has a shape similar to a sphere, or by a diameter of a circle obtained by converting a projected area to a circle having the same area when the silver halide grain has a shape other than the shapes described above.
The difference in grain size between Grain A and Grain B is not particularly limited, but said difference in grain size is preferably smaller, and no difference in grain size is most preferred.
The grain size distribution of the silver halide grain contained in the silver halide emulsion before mixing to be used in the silver halide emulsion layer according to the present invention may be polydispersed, but preferably monodispersed . There may be preferably used a monodispersed silver halide grain having the variation coefficient of the grain size distribution of the silver halide grain of 0.22 or less, more preferably 0.15 or less. Said variation coefficient is a coefficient showing a width of the grain size distribution, and represented by (standard deviation of grain size distribution/average grain size).
The silver halide emulsion according to the present invention may be subjected to gold sulfur sensitization, and it may be also subjected to chemical sensitization by at least one selected from sulfur sensitization, selenium sensitization, noble metal sensitization and reducing sensitization. The silver halide emulsions to be mixed are preferably chemically sensitized, separately.
When the present invention is applied to a light-sensitive color photographic material, there may be generally used a yellow dye-forming coupler in a blue-sensitive emulsion layer, a magenta dye-forming coupler in a green-sensitive emulsion layer and a cyan dye-forming coupler in a red-sensitive emulsion layer. However, depending on the purpose, a light-sensitive silver halide color photographic material may be prepared by using a different combination from the above.
It is desired that these dye-forming couplers have, in their molecules, a so-called ballast group having 8 or more carbon atoms, which can made a coupler nondiffusible. Further, these dye-forming couplers may be either a four equivalent coupler in which four molecules of silver ions are required to be reduced for forming one molacule of a dye, or a two equivalent coupler in which only two molecules of silver ions are required to be reduced.
As the yellow dye-forming coupler, there may be preferably used various acylacetanilide type couplers. Among these, benzoyl acetanilide type and pivaloyl acetanilide type compounds are advantegeous.
As the cyan dye-forming coupler, there may be preferably used a naphthol type coupler and a phenol type coupler.
The compounds such as the dye-forming couplers of the light-sensitive material of the present invention are generally dissolved by using a high boiling point organic solvent having a boiling point of about 150 °C or higher or a water-insoluble polymer, and if necessary, in combination with a low boiling point and/or water-soluble organic solvent, emulsified and dispersed in a hydrophilic binder such as an aqueous gelatin solution by using a surfactant, and then added to a desired hydrophilic colloid layer. A step of removing a dispersing medium or a low boiling point organic solvent similtaneously with dispersion may be added.
The high boiling point organic solvent is preferably a compound having a dielectric constant of 6.5 or less, for example, esters such as phthalate and phosphate, organic acid amides, ketones and hydrocarbon compounds each having a dielectric constant of 6.5 or less.
Further preferred is a high boiling point organic solvent having a dielectric constant of 1.9 to 6.5 and a vapor pressure at 100 °C of 0.5 mmHg or lower. Among these, phthalates and phosphates are more preferred. Most preferred is dialkyl phthalate having an alkyl group with 9 or more carbon atoms. Further, the high boiling point organic solvent may be a mixture of two or more solvents. The dielectric constant means a dielectric constant at 30 °C.
These high boiling point organic solvents are generally used in an amount of 0 to 400 % by weight based on a coupler, preferably 10 to 100 % by weight based on a coupler.
The light-sensitive material of the present invention may be, for example, negative films for a color negative, positive films and a color printing paper. Particularly when a color printing paper provided for direct observation is used, the effect of the present invention can be exhibited efficiently.
The light-sensitive material of the present invention including this color printing paper may be for monochrome or for multicolor.
The silver halide emulsion to be used in the present invention may be optically sensitized to a desired wavelength by using a dye known as a sensitizing dye in the photographic field.
As a binder to be used in the light-sensitive silver halide photographic material of the present invention, gelatin is preferably used.
The gelatin generally used in the photographic industry may include alkali-treated gelatin treated with lime and acid-treated gelatin treated with hydrochloric acid during preparation from collagen, and may be generally prepared by using a cattle bone, oxhide and pigskin as a starting material.
The detailed preparation methods and properties of these gelatins are described in, for example, Arthur Veis, "The Macromolecular Chemistry of Gelatin", Academic Press, pp. 187 to 217 (1964), T.H. James, "The Theory of the Photographic Process", 4th edition, 1977 (Macmillan), p. 55, "Scientific Photograph Handbook" (First volume), pp. 72 to 75 (Maruzen) and "Basis of Photographic Industry - Silver Salt Photograph", pp. 119 to 124 (Corona Co.)
The gelatin to be used in the light-sensitive material of the present invention may be either lime-treated gelatin or acid-treated gelatin prepared by using any of a cattle bone, oxhide and pigskin as a starting material, preferably lime-treated gelatin prepared by using a cattle bone as a starting material.
The photographic emulsion layer and other hydrophilic colloid layers of the light-sensitive material of the present invention can be hardened by crosslinking binder (or protective colloid) molecules using a hardener for increasing film strength singly or in combination.
The hardener is preferably added to such an amount that the light-sensitive material can be hardened without necessity of adding a hardener to a processing solution, but the hardener may be also added to a processing solution.
In the hydrophilic colloid layers such as a protective layer and an intermediate layer of the light-sensitive material of the present invention, a UV absorber may be contained for preventing fog due to discharge caused by charging of the light-sensitive material with friction and preventing deterioration of images by UV ray.
To the light-sensitive material of the present invention, auxiliary layers such as a filter layer, an antihalation layer and/or an antiirradiation layer may be provided. In these layers and/or the emulsion layer, a dye which flows out from the light-sensitive color material during development processing or bleached may be contained.
To the silver halide emulsion layer and/or other hydrophilic colloid layers of the light-sensitive material of the present invention, a matting agent may be added for the purposes of reducing gloss, enhancing writability and preventing mutual adhesion of the light-sensitive material.
To the light-sensitive material of the present invention, a lubricant may be added for reducing sliding friction.
To the light-sensitive material of the present invention, an antistatic agent may be added for the purpose of preventing static charge. The antistatic agent may be used in an antistatic layer at the side of the support on which emulsion layers are not laminated, or may be used in emulsion layers and/or a protective colloid layer other than the emulsion layers at the side of the support on which emulsion layers are laminated.
In the photographic emulsion layer and/or other hydrophilic colloid layers of the light-sensitive material of the present invention, various surfactants may be used for the purposes of improving coatability, preventing static charge, improving sliding property, improving emulsification and dispersion, preventing adhesion and improving photographic characteristics (such as acceleration of development, hardening and sensitization).
The photographic emulsion layer and other layers of the light-sensitive material of the present invention may be coated on a baryta paper, a paper laminated with an α-olefin polymer and a paper support in which a paper support and an α-olefin polymer can be easily peeled off; a flexible reflective support such as a synthetic paper; a reflective support coated with a film comprising a semisynthetic or synthetic polymer such as cellulose acetate, cellulose nitrate, polystyrene, polyvinyl chloride, polyethylene terephthalate, polycarbonate and polyamide, and a white pigment; and a rigid body such as a glass, metal and ceramic. A thin reflective support having a thickness of 120 to 160 µm may be also used.
The support to be used in the light-sensitive material of the present invention may be either a reflective support or a transparent support. For imparting reflecting property, a white pigment may be contained in the support, or a hydrophilic colloid layer containing a white pigment may be coated on the support.
As the white pigment, inorganic and/or organic white pigments may be used, and preferred is an inorganic white pigment. As such a pigment, there may be mentioned sulfate of an alkaline earth metal such as barium sulfate, carbonate of an alkaline earth metal such as calcium carbonate, silicas such as fine powder of silicic acid and synthetic silicates, calcium silicate, alumina, alumina hydrate, titanium oxide, zinc oxide, talc and clay. The white pigment is preferably barium sulfate and titanium oxide.
The light-sensitive material of the present invention may be coated directly or by using a substrate (at least one substrate for improving adhesion property of a support surface, antistatic property, dimensional stability, friction resistance, hardeness, antihalation property, friction characteristic and/or other characteristics) after the support surface is subjected to corona discharging, irradiation of UV ray and flame treatment, if necessary.
When the silver halide emulsion of the present invention is coated, a thickener may be used for increasing coatability. As the coating method, there may be particularly useful extrusion coating and curtain coating by which two or more layers can be coated at the same time.
In the processing of the light-sensitive material of the present invention, a color developing agent to be used in a color developing solution may include known agents widely used in various color photographic processes.
These developers may include aminophenol type and p-phenylenediamine type derivatives. These compounds are generally used in the form of a salt, for example, in the form of a hydrochloride or a sulfate since they are more stable as compared with those under free state. These compounds are generally preferably used at a concentration of 0.1 to 30 g per liter of a color developing solution, more preferably at a concentration of about 1 g to about 15 g per liter of a color developing solution.
As the aminophenol type developer, there may be included, for example, o-aminophenol, p-aminophenol, 5-amino-2-oxytoluene, 2-amino-3-oxytoluene and 2-oxy-3-amino-1,4-dimethylbenzene.
The particularly useful primary aromatic amine type color developer is N,N-dialkyl-p-phenylenediamine type compounds, and the alkyl group and phenyl group may be substituted by a desired substituent. Among them, examples of the particularly useful compound may include N,N-diethyl-p-phenylenediamine hydrochloride, N-methyl-p-phenylenediamine hydrochloride, N,N-dimethyl-p-phenylenediamine hydrochloride, 2-amino-5-(N-ethyl-N-dodecylamino)toluene, N-ethyl-N-β-methanesulfonamidoethyl-3-methyl-4-aminoaniline sulfate, N-ethyl-N-β-hydroxyethylaminoaniline, 4-amino-3-methyl-N,N-diethylaniline and 4-amino-N-(2-methoxyethyl)-N-ethyl-3-methylaniline-p-toluenesulfonate.
To the color developing solution suitably used in the processing of the light-sensitive material of the present invention, in addition to the above primary aromatic amine type color developer, a known developing solution component compound may be added. For example, an alkali agent such as sodium hydroxide, sodium carbonate and potassium carbonate, alkali metal sulfite, alkali metal bisulfite, alkali metal thiocyanate, alkali metal halide, benzyl alcohol, a water softener and a thickening agent may be contained as desired.
The pH value of the color developing solution is generally 7 or more, most generally about 10 to 13.
The color development temperature is generally 15 °C or higher, usually in the range of 20 °C to 50 °C. For rapid development, color development is preferably carried out at 30 °C or higher. The color development time is generally preferably in the range of 20 seconds to 60 seconds, more preferably in the range of 30 seconds to 50 seconds.
The light-sensitive material of the present invention contains the color developing agent in a hydrophilic colloid layer as such or as a precursor thereof, and may be treated by an alkaline activating bath. The precursor of the color developing agent is a compound which can form a color developing agent under alkali conditions, and may include a Schiff base type precursor with an aromatic aldehyde derivative, a polyvalent metal ion complex precursor, a phthalimide derivative precursor, a phosphoric acid amide derivative precursor, a sugar amine reaction product precursor and an urethane type precursor. These precursors of the aromatic primary amine color developing agents are disclosed in U.S. Patents No. 3,342,599, No. 2,507,114, No. 2,695,234 and No. 3,719,492, U.K. Patent No. 803,783, Japanese Provisional Patent Publications No. 185628/1978 and No. 79035/1979, and Research Disclosures No. 15159, No. 12146 and No. 13924. These aromatic primary amine color developing agents or precursors thereof are required to be added to such an amount that sufficient color development can be obtained by that amount when activation processing is carried out. This amount varies greatly depending on the kind of the light-sensitive material, but may be generally between 0.1 mole to 5 mole, preferably in the range of 0.5 mole to 3 mole per mole of silver halide. These color developing agents and precursors thereof may be used singly or in combination.
For incorporating into the light-sensitive material, these color developing agents and precursors thereof may be added by dissolving them in a suitable solvent such as water, methanol, ethanol and acetone, or may be added by preparing an emulsified dispersion by using a high boiling point organic solvent such as dibutyl phthalate, dioctyl phthalate and tricresyl phosphate, or else may be added by impregnating a latex polymer therewith as described in Research Disclosure No. 14850.
The light-sensitive material of the present invention is subjected to bleaching processing and fixing processing after color development. Bleaching processing may be carried out simultaneously with fixing processing.
As a bleaching agent, various compounds are used, and among them, there may be used polyvalent metal compounds such as iron (III), cobalt (III) and copper (II), particularly complex salts of these polyvalent metal cations with an organic acid, for example, an aminopolycarboxylic acid such as ethylenediaminetetraacetic acid, nitrilotriacetic acid and N-hydroxyethylethylenediaminediacetic acid, a metal complex salt of an acid such as malonic acid, tartaic acid, malic acid, diglycolic acid and dithioglycolic acid, ferricyanates and bichromic acid singly or in a suitable combination.
As a fixing agent, there may be used a soluble complexing agent with which silver halide is made a complex salt to become soluble. As the soluble complexing agent, there may be mentioned, for example, sodium thiosulfate, ammonium thiosulfate, potassium thiocyanate, thiourea and thioether.
After fixing processing, washing processing is generally carried out. As a substitution for washing processing, stabilizing processing may be carried out, or both processings may be also carried out in combination. In a stabilizing solution to be used in the stabilizing processing, a pH controlling agent, a chelating agent and an antifungal agent may be contained.
Japanese Provisional Patent Publication No. 134636/1983 may be referred to about these specific conditions.

EXAMPLES

The present invention is described in detail by referring to Examples.

Example 1

On a paper support having one side laminated with polyethylene and another side laminated with polyethylene containing titanium oxide, the respective layers having the following constitutions were provided by coating at the side of the polyethylene layer containing titanium oxide to prepare multilayer light-sensitive silver halide color photographic material samples (Samples No. 101 to No. 107). The coating solutions were prepared as described below.

First layer coating solution

To 26.7 g of a yellow coupler (Y-1), 10.0 g of a dye image stabilizer (ST-1), 6.67 g of (ST-2), 0.67 g of an additive (HQ-1) and 6.67 g of a high boiling point organic solvent (DNP) was added 60 ml of ethyl acetate and the mixture was dissolved, and the solution was dispersed by emulsification in 220 ml of a 10 % aqueous gelatin solution containing 7 ml of a 20 % surfactant (SU-1) by means of an ultrasonic homogenizer to prepare a yellow coupler dispersion. The dispersion was mixed with a blue-sensitive silver halide emulsion (containing 10 g of silver) prepared under the following conditions to prepare a first layer coating solution.
The second layer to the seventh layer coating solutions were prepared in the same manner as in the above first layer coating solution.
As a hardener, (H-1) was added in the second and the fourth layer, and (H-2) was added in the seventh layer. As a coating aid, surfactants (SU-2) and (SU-3) were added in order to control surface tension.
The constitutions of the first layer to the seventh layer are shown in the following Table 1.
The amount of the silver halide emulsion added are shown by calculating on silver.

DOP: Dioctyl phthalate
DNP: Dinonyl phthalate
DIDP: Diisodecyl phthalate
PVP: Polyvinyl pyrrolidone

(Preparation method of blue-sensitive silver halide emulsion)

To 1,000 ml of a 2 % aqueous gelatin solution maintained at 40 °C were added the following (A solution) and (B solution) simultaneously over 30 minutes under controlling pAg = 6.5 and pH = 3.0, and further the following (C solution) and (D solution) were added simultaneously over 180 minutes under controlling pAg = 7.3 and pH = 5.5. During this addition, the pAg was controlled according to the method disclosed in Japanese Provisional Patent Publication No. 45437/1984, and the pH was controlled by using an aqueous solution of sulfuric acid or sodium hydroxide.
After completion of the addition, desalting was effected by using a 5 % aqueous solution of Demol N (trade name) produced by Kao Atlas K.K. and a 20 % aqueous solution of magnesium sulfate, and then the solution was mixed with an aqueous gelatin solution to obtain a monodispersed cubic emulsion EMP-1 having an average grain size of 0.85 µm, a variation coefficient (σ/ $\bar{r}$
) of grain size distribution = 0.07 and a silver chloride content of 99.5 mole %.
By using the following compounds, the above emulsion EMP-1 was chemically ripened at 50 °C for 90 minutes to obtain a blue-sensitive silver halide emulsion (Em-B).

(Preparation method of red-sensitive silver halide emulsion)

The procedures were carried out in the same manner as in EMP-1 except for changing the addition time of (A solution) and (B solution) and the addition time of (C solution) and (D solution) to obtain a monodispersed cubic emulsion EMP-2 having an average grain size of 0.50 µm, a variation coefficient (σ/ $\bar{r}$
) of grain size distribution = 0.08 and a silver chloride content of 99.5 mole %.
By using the following compounds, the emulsion EMP-2 was chemically ripened at 60 °C for 90 minutes to obtain a red-sensitive silver halide emulsion (Em-R).

(Preparation of silver halide emulsion (Em-1))

In the following, the amount of an additive used at the time of preparing an emulsion is an amount per mole of silver halide unless otherwise indicated.
A silver nitrate solution and a sodium chloride solution were added to an inactive aqueous gelatin solution over 120 minutes by a double jet method. During this addition, the temperature and pAg were maintained at 40 °C and 7.3, respectively, and 9.3 x 10⁻⁹ mole/mole of AgX of K₂IrCl₆ was added during formation of silver halide grains.
Subsequently, desalting and washing were carried out according to a conventional method to obtain Em-1 comprising a cubic silver chloride grain having an average grain size of 0.50 µm and a variation coefficient of grain size distribution of 0.09.
The amount of K₂IrCl₆ added to this emulsion was 4.5 x 10⁻²³ mole/grain.

(Preparation of silver halide emulsion (Em-2))

The procedures were carried out under the same conditions as in Em-1 except for adding 2.5 x 10⁻⁸ mole/mole of AgX of K₂IrCl₆ during formation of silver halide grains to obtain Em-2 comprising a cubic silver chloride grain having an average grain size of 0.50 µm and a variation coefficient of grain size distribution of 0.08.
The amount of K₂IrCl₆ added to this emulsion was 1.2 x 10⁻²² mole/grain.

(Preparation of silver halide emulsion (Em-3))

The procedures were carried out in the same as in Em-1 except for adding 1.2 x 10⁻⁸ mole/mole of AgX of K₂IrCl₆ during formation of silver halide grains and changing the addition time to be shorter by 20 minutes than the addition time in the case of Em-1 to obtain Em-3 comprising a cubic silver chloride grain having an average grain size of 0.45 µm and a variation coefficient of grain size distribution of 0.08.
The amount of K₂IrCl₆ added to this emulsion was 4.2 x 10⁻²³ mole/grain.
By using the following compounds, the above respective emulsions were chemically ripened at 55 °C for 120 minutes to obtain green-sensitive silver halide emulsions (Em-G1 to Em-G3).
Samples No. 101 to No. 107 were prepared by combining magenta couplers and the above green-sensitive silver chloride emulsions as shown in Table 2 in the third layer (green-sensitive layer) in Table 1.
Samples No. 101 to No. 103 in which one emulsion was used were prepared for evaluating samples before mixing two kinds of silver halide emulsions, and the illuminance dependency of sensitivity of the samples in which one emulsion was used and that of the sample of the present invention were measured at the same time.

Comparative magenta coupler a

For Samples No. 101 to No. 107 obtained, sensitivity, gradation, illuminance dependency and color reproducibility were evaluated in the following manner.

(Evaluation of sensitivity and gradation)

After the above samples were exposed by a conventional method, the processings described below were carried out, and then sensitometry thereof was carried out.
The sensitivity (S) was represented by a reciprocal of exposure dose necessary for obtaining a reflection density of 0.8, and evaluated with its relative value. The gradation (γ) was represented by a slope of a reflection density from 0.8 to 1.8.

(Evaluation of illuminance dependency)

After the respective samples were subjected to wedge exposure for an exposure time of 0.02 second (high illuminance condition) and for an exposure time of 10 seconds (low illuminance condition) so that the same exposure dose were irradiated, respectively, the illuminance dependency of sensitivity (ΔS) and the illuminance dependency of gradation (Δγ) were examined.
The ΔS is a ratio of sensitivity obtained by exposure under high illuminance condition to sensitivity obtained by exposure under low illuminance condition, and as this value is smaller, the light-sensitive silver halide photographic material has smaller illuminance dependency of sensitivity.
The Δγ is a difference between γ obtained by exposure under low illuminance condition and γ obtained by exposure under high illuminance condition, and as an absolute value of this value is smaller, the light-sensitive silver halide photographic material is an excellent material having smaller illuminance dependency of gradation.

(Evaluation of color reproducibility)

Next, after the respective samples were subjected to wedge exposure with green light, the same procedures as in the above evaluation of sensitivity and gradation were carried out, and then spectral absorption characteristic (secondary absorption at 430 nm) of the magenta color-developed samples was measured.

(Spectral absorption characteristic test)

Spectral reflection spectra of the magenta color-developed samples were measured by using a color analyzer Model 607 (trade name, manufactured by Hitachi Ltd.). At this time, measurement was carried out by standardizing the maximum density of an absorption spectrum at a visible portion of each sample to be 1.0.
Next, the absorbance at 440 nm at a visible portion (magenta) of each sample was read, and this value was regarded as a standard of unnecessary absorption at a yellow portion and defined as secondary absorption.
The light-sensitive material having small secondary absorption can be said to be a light-sensitive silver halide photographic material excellent in color reproducibility.
In order to clarify the constitution of the present invention, some of the effects on the illuminance dependency of sensitivity of the emulsions before mixing are selected and shown in Table 3.
Next, the results of sensitivity, illuminance dependencies (ΔS and Δγ) and spectral absorption characteristic are shown in Table 4.
As clearly seen from Table 4, (1) as compared with the comparative couplers, in the coupler of the present invention, the secondary absorption is small and sharp images can be obtained, but the illuminance dependency of gradation is worsened; and (2) when two kinds of silver halide emulsions having different sensitivities are mixed, if the illuminance dependency of sensitivity of the silver halide emulsion having lower sensitivity is smaller than that of the silver halide emulsion having higher sensitivity, the illuminance dependency of gradation is improved as compared with the case of the single emulsion even when the comparative coupler is used, but the degree of improvement is insufficient. In this case, when the coupler represented by the formula (M-I) of the present invention is used, the illuminance dependency of gradation is further improved, and the color reproducibility is also good.

Example 2

On a paper support having one side laminated with polyethylene and another side laminated with polyethylene containing titanium oxide at the side of the first layer, the respective layers having the constitutions shown in Table 5 were provided by coating to prepare multilayer light-sensitive silver halide color photographic material samples. The coating solutions were prepared as described below.

First layer coating solution

To 26.5 g of a yellow coupler (Y-2), 10.0 g of a dye image stabilizer (ST-1), 0.46 g of an additive (HQ-1) and 10 g of a high boiling point organic solvent (DNP) was added 60 ml of ethyl acetate and the mixture was dissolved, and the solution was dispersed by emulsification in 220 ml of a 10 % aqueous gelatin solution containing 7 ml of a 20 % surfactant (SU-1) by means of an ultrasonic homogenizer to prepare a yellow coupler dispersion. The dispersion was mixed with a blue-sensitive silver halide emulsion (containing 10 g of silver) prepared under the following conditions to prepare a first layer coating solution.
The second layer to the seventh layer coating solutions were prepared in the same manner as in the above first layer coating solution.
As a coating aid, SU-4 and SU-5 were used, and as a hardener, H-1 and H-2 were used.
The respective color-sensitive emulsions were prepared as described below.

(Blue-sensitive silver chlorobromide emulsion)

A silver chlorobromide emulsion having an average grain size of 0.7 µm and a silver bromide content of 90 mole % was optimumly sensitized at 57 °C by using sodium thiosulfate and a sensitizing dye (BS-2), and Z-1 was added as a stabilizer.

(Red-sensitive silver chlorobromide emulsion)

A silver chlorobromide emulsion having an average grain size of 0.4 µm and a silver bromide content of 60 mole % was optimumly sensitized at 60 °C by using sodium thiosulfate, a sensitizing dye (RS-2) and a phenol resin, and Z-1 was added as a stabilizer.

(Preparation of silver halide emulsion (EM-4))

A silver nitrate solution and a solution mixture of potassium bromide and sodium chloride were added to an inactive aqueous gelatin solution over 140 minutes by a double jet method. During this addition, the temperature and pAg were maintained at 50 °C and 7.5, respectively, and 6.1 x 10⁻⁹ mole/mole of AgX of K₂IrCl₆ was added during formation of grains.
Subsequently, desalting and washing were carried out according to a conventional method to obtain a silver halide emulsion Em-4. Em-4 comprises a tetradecahedral silver chlorobromide grain having an average grain size of 0.52 µm, a silver bromide content of 70 mole % and a variation coefficient of grain size distribution of 0.10.
The amount of K₂IrCl₆ added to this emulsion was 3.3 x 10⁻²³ mole/grain.

(Preparation of silver halide emulsions (Em-5 to Em-8))

The procedures were carried out in the same manner as in Em-4 except for changing the amount of K₂IrCl₆ and the addition time to obtain emulsions Em-5 to Em-8.
In Table 6, each content, average grain size, variation coefficient of grain size distribution and average amount of K₂IrCl₆ added per grain of silver halide are shown.

(Preparation of silver halide emulsion (Em-9))

An aqueous silver nitrate solution and an aqueous halide solution (mixed aqueous solution of potassium bromide and potassium iodide) were added to an inactive gelatin aqueous solution over 120 minutes by a double jet method. During this addition, the temperature and pAg were maintained at 60 °C and 9.0, respectively, and 9.3 x 10⁻⁹ mole/mole of AgX of K₂IrCl₆ was added during formation of grains.
Subsequently, desalting and washing were carried out according to a conventional method to obtain a silver halide emulsion Em-9. Em-9 was an emulsion comprising a silver iodobromide grain having an average grain size of 0.5 µm, a silver iodide content of 2 mole % and a variation coefficient of grain size distribution of 0.13, and K₂IrCl₆ added to this emulsion was 4.5 x 10⁻²³ mole/grain.

(Preparation of silver halide emulsion (Em-10))

An aqueous silver nitrate solution and an aqueous halide solution (mixed aqueous solution of potassium bromide and potassium iodide) were added to an inactive gelatin aqueous solution over 120 minutes by a double jet method. During this addition, the temperature and pAg were maintained at 60 °C and 9.0, respectively, and 2.5 x 10⁻⁸ mole/mole of AgX of K₂IrCl₆ was added during formation of grains.
Subsequently, desalting and washing were carried out according to a conventional method to obtain a silver halide emulsion Em-10. Em-10 was an emulsion comprising a silver iodobromide grain having an average grain size of 0.50 µm, a silver iodide content of 2.5 mole % and a variation coefficient of grain size distribution of 0.14, and K₂IrCl₆ added to this emulsion was 1.2 x 10⁻²² mole/grain.
By using the following compounds, the above respective emulsions were optimumly chemically sensitized at 59 °C to obtain green-sensitive silver halide emulsions (Em-G4 to Em-G10).
Samples No. 201 to No. 218 were prepared by combining magenta couplers and the above green-sensitive silver chloride emulsions as shown in Table 7 in the third layer (green-sensitive layer) in Table 5.
Samples No. 201 to No. 207 in which one emulsion was used were samples before mixing two kinds of silver halide emulsions, and the illuminance dependency of sensitivity of the samples in which one emulsion was used and that of the samples of the present invention were measured at the same time.
After Samples No. 201 to No. 218 were exposed in the same manner as in Example 1, the processings were carried out according to the following processing steps, and sensitivity, gradation, illuminance dependency and color reprodubility were evaluated.
Some of the results of the illuminance dependency of sensitivity of the emulsions before mixing are selected and shown in Table 8, and the whole results are shown in Table 9.
From Table 9, it can be understood that when the average amount of iridium added per grain of the silver halide emulsion having lower sensitivity is larger than that of the silver halide emulsion having higher sensitivity, the illuminance dependency of gradation is improved.
When the silver halide grain of the present invention is silver iodobromide, the illuminance dependency of gradation is improved. However, the sensitivity is relatively lower as compared with that of silver chloride or silver chlorobromide, and even when the same coupler is used, the absorption becomes high at around 440 nm, and the color reproducibility is slightly inferior.
From these facts, it is preferred that the silver halide grain to be contained in the silver halide emulsion of the present invention contains substantially no silver iodide.

Example 3

(Preparation of silver halide emulsion (Em-a))

An aqueous silver nitrate solution and an aqueous halide solution (aqueous solution mixture of potassium bromide and sodium chloride) were added to an inactive gelatin aqueous solution over 100 minutes by a double jet method. During this addition, the temperature and pAg were maintained at 50 °C and 7.8, respectively, and 1.3 x 10⁻⁸ mole/mole of AgX of K₂IrCl₆ was added during formation of grains.
Subsequently, desalting and washing were carried out according to a conventional method to obtain Em-a. Em-a was a monodispersed emulsion comprising a cubic silver chlorobromide grain having an average grain size of 0.40 µm, a silver bromide content of 0.10 mole % and a variation coefficient of grain size distribution of 0.12.
The amount of K₂IrCl₆ added to this emulsion was 3.3 x 10⁻²³ mole/grain.

(Preparation of silver halide emulsion (Em-b))

An aqueous silver nitrate solution and an aqueous halide solution (aqueous solution mixture of potassium bromide and sodium chloride) were added to an inactive gelatin aqueous solution over 100 minutes by a double jet method. During this addition, the temperature and pAg were maintained at 50 °C and 7.8, respectively, and 3.3 x 10⁻⁸ mole/mole of AgX of K₂IrCl₆ was added during formation of grains.
Subsequently, desalting and washing were carried out according to a conventional method to obtain Em-b. Em-b was a monodispersed emulsion comprising a cubic silver chlorobromide grain having an average grain size of 0.40 µm, a silver bromide content of 0.10 mole % and a variation coefficient of grain size distribution of 0.11.
The amount of K₂IrCl₆ added to this emulsion was 8.3 x 10⁻²³ mole/grain.

(Preparation of silver halide emulsion (Em-c))

An aqueous silver nitrate solution and an aqueous halide solution (aqueous solution mixture of potassium bromide and sodium chloride) were added to an inactive gelatin aqueous solution over 90 minutes by a double jet method. During this addition, the temperature and pAg were maintained at 50 °C and 7.8, respectively, and 6.6 x 10⁻⁹ mole/mole of AgX of K₂IrCl₆ was added during formation of grains.
Subsequently, desalting and washing were carried out according to a conventional method to obtain Em-c. Em-c was a monodispersed emulsion comprising a cubic silver chlorobromide grain having an average grain size of 0.50 µm, a silver bromide content of 0.10 mole % and a variation coefficient of grain size distribution of 0.11.
The amount of K₂IrCl₆ added to this emulsion was 3.2 x 10⁻²³ mole/grain.
The above respective emulsions were optimumly chemically sensitized at 60 °C under the following conditions to obtain green-sensitive silver halide emulsions (Em-G11 to Em-G16).
In the same manner as in Example 1, there were prepared multilayer light-sensitive silver halide color photographic materials (Samples No. 301 to No. 311) in which the magenta coupler of the present invention and the respective monodispersed silver chlorobromide emulsions were combined as shown in Table 11.
Samples No. 301 to No. 306 in which one emulsion was used were samples before mixing two kinds of silver halide emulsions, and the illuminance dependency of sensitivity of the samples in which one emulsion was used and that of the sample of the present invention were measured at the same time.
Samples No. 301 to No. 311 were exposed and processed in the same manner as in Example 1, and evaluated.
Some of the results of the illuminance dependency of sensitivity of the emulsions before mixing are selected and shown in Table 12, and the whole results are shown in Table 13.
From Table 13, it can be understood that in the present invention, a method of making the illuminance dependency of sensitivity of the silver halide emulsion having lower sensitivity smaller than the illuminance dependency of sensitivity of the silver halide emulsion having higher sensitivity can be carried out not only by changing the amount of a water-soluble iridium compound to be added but also by changing the conditions of chemical sensitization, for example, extending the chemical ripening time or increasing the amount of sodium thiosulfate, but the method of changing the amount of a water-soluble iridium compound to be added is the most excellent.

Example 4

The procedures were carried out in the same manner as in Example 3 except for changing the magenta coupler M-22 in Sample No. 311 to Exemplary compound 1, 4, 10, 20, 35, 59, 61 or 63, respectively, to prepare samples. When the samples were evaluated in the same manner, the effect of the present invention was obtained.
The present invention can provide a novel technique for improving reciprocity law failure property of a light-sensitive material, whereby illuminance dependency of gradation can be improved without lowering sensitivity. Thus, according to the present invention, a light-sensitive material having high sensitivity and excellent in gradation property and color reproducibility can be provided.

Claims

A light-sensitive silver halide photographic material having at least one silver halide emulsion layer on a support, characterized in that at least one of the above silver halide emulsion layers contains a coupler represented by the following formula (M-I), a silver halide grain contained in said silver halide emulsion layer is a mixture of at least two kinds of silver halide emulsions different in sensitivity, and the illuminance dependency of sensitivity of the silver halide emulsion having lower sensitivity is smaller than the illuminance dependency of sensitivity of the silver halide emulsion having higher sensitivity
wherein Z represents a group of non-metallic atoms necessary for forming a nigrogen-containing heterocyclic ring and the ring formed by said Z may have a substituent; X represents hydrogen atom or an eliminatable group by reaction with an oxidized product of a color developing agent; and R represents hydrogen atom or a substituent.
The material of Claim 1 wherein R is selected from the group consisting of hydrogen atom, each group of alkyl, aryl, anilino, acylamino, sulfonamide, alkylthio, arylthio, alkenyl and cycloalkyl, a halogen atom, each group of cycloalkenyl, alkynyl, heterocyclic ring, sulfonyl, sulfinyl, phosphonyl, acyl, carbamoyl, sulfamoyl, cyano, alkoxy, aryloxy, heterocyclic oxy, siloxy, acyloxy, carbamoyloxy, amino, alkylamino, imido, ureido, sulfamoylamino, alkoxycarbonylamino, aryloxycarbonylamino, alkoxycarbonyl, aryloxycarbonyl and heterocyclic thio, a spiro compound residue, and a bridged hydrocarbon compound residue.
The material of Claim 1 wherein X is an eliminatable group by reaction with an oxidized product of a color developing agent selected from the group consisting of chlorine atom, bromine atom and fluorine atom, each group of alkoxy, aryloxy, heterocyclic oxy, acyloxy, sulfonyloxy, alkoxycarbonyloxy, aryloxycarbonyl, alkyloxalyloxy, alkoxyoxalyloxy, alkylthio, arylthio, heterocyclic thio, alkyloxythiocarbonylthio, acylamino, sulfonamide, nitrogen-containing heterocyclic ring bonded by N atom, alkyloxycarbonylamino, aryloxycarbonylamino, carboxyl and
where R₁′ has the same meaning as the above R; Z′ has the same meaning as Z in Claim 1; R₂′ and R₃′ each represent hydrogen atom, an aryl group, an alkyl group or a heterocyclic group.
The material of Claim 1 wherein X is chlorine atom.
The material of Claim 1 wherein the ring formed by Z is a pyrazole ring, an imidazole ring, a triazole ring or a tetrazole ring.
The material of Claim 1 wherein the above silver halide grain contained in at least two kinds of silver halide emulsions having different sensitivities comprises silver chloride or silver chlorobromide substantially containing no silver iodide.
The material of Claim 1 wherein the illuminance dependency of sensitivity of the silver halide emulsion is controlled by an amount of a water-soluble iridium compound to be added at formation or growth of silver halide grains.
The material of Claim 7 wherein the water soluble-iridium compound is iridium trichloride, iridium tribromide, potassium hexachloroiridium (III), ammonium iridium (III) sulfate, potassium iridium (III) disulfate, tripotassium iridium (III) trisulfate, iridium (III) sulfate, iridium (III) trioxalate, iridium tetrachloride, iridium tetrabromide, potassium hexachloroiridium (IV), ammonium hexachloroiridium (IV), potassium iridate (IV) or iridium (IV) trioxalate.
The material of Claim 7 wherein the average amount of the water-soluble iridium compound added per grain of the silver halide emulsion having lower sensitivity is larger than that of the silver halide emulsion having higher sensitivity.
The material of Claim 7 wherein the amount of the water-soluble iridium compound added is 2 x 10⁻²³ to 5 x 10⁻¹⁶ mole/grain in the emulsion having lower sensitivity and 2 x 10⁻²⁴ to 2 x 10⁻¹⁸ mole/grain in the emulsion having higher sensitivity.
The material of Claim 10 wherein the amount of the water-soluble iridium compound added is 2 x 10⁻²³ to 5 x 10⁻¹⁸ mole/grain in the emulsion having lower sensitivity and 2 x 10⁻²⁴ to 2 x 10⁻²⁰ mole/grain in the emulsion having higher sensitivity.