The present invention relates to a silver halide color photographic light-sensitive material with improved color reproducibility, specifically to a silver halide color photographic light-sensitive material improved in reproducibility for red.

In recent years, silver halide color photographic light-sensitive materials have attained remarkable improvements in image quality. Light-sensitive materials now on the market are excellent in graininess, sharpness and color reproducibility, which are the three major determinants of image quality, and, it seems that photoprints and slide films obtained from these light-sensitive materials almost satisfy users' requirement.

Graininess and sharpness have been improved remarkably by the use of smaller-sized silver halide grains. As for color reproducibility, while high-purity color images have come to be produced, there is yet room for improvement in the reproduction of hues. Some subjects have very high reflections and some have very low reflections. It is extremely difficult to photographically reproduce the hues of these subjects with a high degree of accuracy.

To realize more faithful reproduction of colors, extensive studies have been made on masking, interimage effect and spectral sensitivity distribution. Details of interimage effect are described in Hanson et al, Journal of the Optical Society of America, Vol. 42, pp. 663-669, and A. Thiels, Zeitschrift fur Wissenschaftliche Photographic, Photopysique und Photochemie, Vol. 47, pp. 106-118 and pp. 246-255.

U.S. Patent No. 3,672,898 discloses a silver halide color photographic light-sensitive material having a specific spectral sensitivity distribution, with which a variation in color balance caused by a change in light source (e.g. sun, fluorescent lamp, tungsten lamp) can be minimized. It is also known in the art that the saturation of a primary color, such as red, green and blue, can be recorded accurately when the color-sensitive layers of a light-sensitive material each have a sharp spectral sensitivity distribution.

Interimage effect or sharp spectral distribution allows the saturation of a color to be reproduced faithfully, but, at the same time, hinders the exact reproduction of delicate shades of a primary color. In parts of an image where the primary color of a subject is reproduced, the gradation of its complementary color tends to be lost or get softer due to the manifestation of interimage effect. This is the serious disadvantage of interimage effect.

The inventors of the present invention made extensive studies, and have found that the above problem can be avoided when D_N2-D_R2 and D_N16-D_R16 (which will be defined later) are adjusted to specific values. By adjusting D_N2-D_R2 and D_N16-D_R16 to specific values, it has become possible to reproduce red in a lower to medium density region accurately with a higher saturation, as well as to reproduce the delicate shades of red in a higher density region.

The object of the invention is to provide a silver halide color photographic light-sensitive material which can reproduce red in a lower to medium density region accurately with a higher saturation, and, at the same time, can reproduce the delicate shades of red in a higher density region.

The above object can be attained by a silver halide photographic light-sensitive material comprising a support and provided thereon at least one red-sensitive silver halide emulsion layer, at least one green-sensitive silver halide emulsion layer and at least one blue-sensitive silver halide emulsion layer, wherein red density D_N2 obtained after exposing said light-sensitive material to 2/S·lux·sec (wherein S is the ISO sensitivity of said light-sensitive material) of white light and red density D_R2 obtained after exposing said light-sensitive material to 2/S·lux·sec (wherein S is as defined above) of white light through a red filter satisfy the following inequality: 2.0 ≧ D_N2-D_R2 ≧ 0.13; and red density D_N16 obtained after exposing said light-sensitive material to 16/S·lux·sec (wherein S is as defined above) of white light and red density D_R16 obtained after exposing said light-sensitive material to 16_/S·lux·sec (wherein S is as defined above) of white light through a red filter satisfy the following inequality: 0.06 ≧ D_N16-D_R16 ≧ 0 ,provided that the red filter is a filter having a transmittance of 2% or less at 350 to 585 nm, 80% or more at 630 to 800 nm, and attaining a 50% transmittance at a certain point in the wavelength region 600 to 610 nm.

The ISO sensitivity of a silver halide color photographic light-sensitive material is obtained by the method prescribed in ISO5800 (1979)[E]. Red density D_N2 is defined as a density obtained by exposing a light-sensitive material having an ISO sensitivity of S to white light emitted from a light source having the same spectral energy distribution as that of a light source employed for the ISO sensitivity measurement under the following exposure conditions: shutter speed, same as that employed for the ISO sensitivity measurement; exposure, 2 × 1/S·lux·sec. Red density D_R2 is defined as a density which is obtained in the same manner as mentioned above, except that the exposure is performed using a red filter.

As mentioned above, a red filter is a filter having a transmittance of 2% or less at 350 to 585 nm, 80% or more at 630 to 800 nm, and attaining a 50% transmittance at a certain point in the wavelength region 600 to 610 nm. Wratten (gelatin) filter No. 26 manufactured and sold by Eastman Kodak Co., Ltd. is one example of commercially available red filters.

Red density D_N16 is defined as a density obtained in the same manner as that employed for the D_N2 measurement, except that the exposure is 16 × 1/S·lux·sec. Red density D_R16 is defined as a density obtained in the same manner as that employed for the D_N16 measurement, except that the exposure is conducted through a red filter.

In each of these red density measurements, after exposure, a light-sensitive material is left at 20 ±5°C and RH60 ±10%, and then processed for 0.5 to 6 hours by processing methods recommended by film manufacturers.

The density is the Status M density prescribed in 1505/3-1984 (E). The density measurement is conducted by the method prescribed by ISO, using a densitometer manufactured and sold by X-RITE Co., Ltd. (Model 310).

In the invention, red sensitivities D_N2, D_R2, D_N16 and D_R16 should satisfy the following inequalities:



        2.0 ≧ D_N2-D_R2 ≧ 0.13; and




        0.06 ≧ D_N16-D_R16 ≧ 0



When D_N2-D_R2 and D_N16-D_R16 are adjusted to such values, a light-sensitive material can reproduce red in a lower to medium density region accurately with a higher saturation, and at the same time, can reproduce faithfully the delicate shades of red in a higher density region.

When a subject of red with a higher saturation and a higher density is photographed, the resulting negative image has a gradation. However, such gradation tends to be lost during the printing of the negative image on color paper, since the density of the negative image is likely to change by an amount that is beyond the latitude of the color paper.

Such loss of gradation can be avoided by making the gradation and density of a negative image softer and lower, respectively. However, if a negative image has a softer gradation and a lower density, red, in particular, skin color of a subject reproduced on color paper inevitably has a lower saturation.

The inventors have found that the above problem can be solved by adequately controlling the spectral sensitivity distribution of the red-sensitive layer and the interimage effect in the blue-, green-, and red-sensitive layers. The spectral sensitivity distribution of the red-sensitive layer can be adjusted, for example, by the use of a spectral sensitizing dye.

In the invention, it is preferred that the red-sensitive emulsion be spectrally sensitized with at least one sensitizing dye represented by Formula 1 and at least one sensitizing dye represented by Formula 2 or 3.

In the formula, R¹ represents a hydrogen atom, an alkyl group or an aryl group; R² and R³ each represent an alkyl group; Y¹ and Y² each represent a sulfur atom or a selenium atom; Z¹, Z², Z³ and Z⁴ each represent a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, an amino group, an acyl group, an acylamino group, an acyloxy group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonyl group, a sulfonyl group, a carbamoyl group, an aryl group, an alkyl group or a cyano group; X¹ represents a cation; and m represents an integer of 1 or 2. Z¹ and Z² may combine with each other to form a ring. The same can be applied to Z³ and Z⁴. When the sensitizing dye forms an intramolecular salt, m is 1.

In the formula, R⁴ represents a hydrogen atom, an alkyl group or an aryl group; R⁵, R⁶, R⁷ and R⁸ each represent an alkyl group; and Y³ represents a nitrogen atom, a sulfur atom or a selenium atom; z⁵, z⁶, Z⁷ and Z⁸ each represent a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, an amino group, an acyl group, an acylamino group, an acyloxy group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylamino group, a carbamoyl group, an aryl group, an alkyl group, a cyano group or a sulfonyl group; X² represents a cation; and n represents an integer of 1 or 2. When y³ is a sulfur atom or a selenium atom, R⁵ is not present. Z⁵ and Z⁶ may combine with each other to form a ring. The same can be applied to Z⁷ and Z⁸. When the sensitizing dye forms an intramolecular salt, n is 1.

In the formula, Y⁵ represents a sulfur atom or a selenium atom; R¹⁸ represents a hydrogen atom, a lower alkyl group or an aryl group; R¹⁰ and R²⁰ each represent a substituted or unsubstituted alkyl group; Z¹⁷, Z¹⁸, Z¹⁹ and Z²⁰ each represent a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, an amino group, an acylamino group, an acyloxy group, an alkoxycarbonyl group, an alkoxycarbonylamino group or a lower alkyl group; X⁵ represents a cation; and Q represents an integer of 1 or 2. Specific examples of the groups represented by Z¹⁷, Z¹⁸, Z¹⁹ or Z²⁰ include those described in various publications published in the photographic industry. Z¹⁷ and Z¹⁸ may combine with each other to form a ring. The same can be applied to Z¹⁹ and Z²⁰. Examples of such ring include a benzene ring. When the sensitizing dye forms an intramolecular salt, Q is 1.

Representative examples of the sensitizing dyes represented by Formula 1 are given below:

Representative examples of the sensitizing dyes represented by Formula 2 are given below:

Representative examples of the sensitizing dyes represented by Formula 3 are given below:

Besides the sensitizing dyes represented by Formula 1, 2 or 3, benzothiazoles and quinolones described in Japanese Patent Examined Publication No. 24533/1982 and quinoline derivatives described in Japanese Patent Examined Publication No. 24899/1982 may optionally be employed as a supersensitizer.

As the sensitizing dye for the red-sensitive layer, it is preferred that at least one sensitizing dye represented by Formula 1 and at least one sensitizing dye represented by Formula 2 be employed in combination. Especially preferable is the combination of a sensitizing dye represented by Formula 1 in which Y¹ and Y² each are a sulfur atom and a sensitizing dye represented by Formula 2 in which Y³ is N-R³ (wherein N is a sulfur atom and R³ is an alkyl group).

Interimage effect can be controlled by the use of a DIR compound. Here, a DIR compound is defined as a compound that can release, upon a coupling reaction with an oxidized development agent, development inhibitor or a compound capable of releasing a development inhibitor.

Examples of usable DIR compounds include Example Compound Nos. D-1 to 37 described in Japanese Patent Publication Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication) No. 77056/1989, pp. 36-64. In the invention, at least one DIR compound is contained in at least one light-sensitive layer, preferably in at least two light-sensitive layers differing in sensitivity.

A development inhibitor to be released from a DIR compound contained in the green-sensitive layer preferably has a diffusibility of 0.34 to 0.60. A development inhibitor to be released from a DIR compound contained in the blue-sensitive layer preferably has a diffusibility of 0.40 to 0.70. The diffusibility of a development inhibitor can be measured by the method described in Japanese Patent O.P.I. Publication No. 77056/1989, pp. 36-42

The amount of a DIR compound is 1.0 × 10⁻⁴ to 1.0 × 10⁻¹ mol, preferably 4.0 × 10⁻⁴ to 5.0 × 10⁻² mol, still preferably 8.0 × 10⁻⁴ to 2.0 × 10⁻² mol, per mol silver halide.

Examples of usable DIR compounds are also described in U.S. Patent Nos. 4,234,678, 3,227,554, 3,617,291, 3,958,993, 4,149,886, 3,933,500, 2,072,363, 2,070,266, Japanese Patent O.P.I. Publication Nos. 56837/1982, 13239/1976 and Research Disclosure No. 21228 (December 1981).

The average grain size d of silver halide grains contained in the high-speed light-sensitive layer is preferably 0.55 µm or less, still preferably 0.47 µm or less, further preferably 0.38 µm or less.

An average grain size d is defined as a diameter d_i that maximizes the product of n_i and d_i³ (wherein n_i means the number of grains having a diameter of d_i). The significant figure is calculated down to the third decimal place and the fourth digit is rounded to the nearest whole number.

The size of a grain is defined as the length of a side of a cube having the same volume as that of the grain.

A silver halide emulsion to be employed in the invention is preferably monodispersed. The "monodispersed emulsion" is defined as an emulsion containing 70% by weight more, preferably 80% by weight or more, still preferably 90% by weight or more, of grains with sizes falling within the range of 80 to 120% of the average grain size d.

In the invention, it is preferable to employ an emulsion consisting of silver halide grains each having in its interior portion a high silver iodide phase. In such silver halide grain, the high silver iodide content phase is covered with a phase containing a smaller amount of silver iodide or a phase containing no silver iodide such as silver chloride phase (these two phases will be referred to as low silver iodide content phases).

The silver iodide content of the high iodide content phase is preferably 15 to 45 mol%, still preferably 20 to 42 mol%, most preferably 25 to 40 mol%.

The low silver iodide content phase may constitute the outermost layer of a silver halide grain. In such case, the average silver iodide content of the low silver iodide content phase is preferably 6 mol% or more, still preferably 0 to 4 mol%. Another silver iodide-containing phase (e.g. a phase with a silver iodide content which is between the silver iodide content of the high silver iodide content phase and that of the low silver iodide content phase) may be present between the high silver iodide content phase and the low silver iodide content phase.

A silver halide emulsion to be employed in the invention may consist of either regular or twin silver halide crystals. It is also possible to employ tabular silver halide crystals with an aspect ratio of 2 or more. Here, an aspect ratio is defined as a grain size/grain thickness ratio (wherein a grain size is defined as the diameter of a circle having the same projection area). A silver halide emulsion to be used in the invention may be chemically sensitized in the usual way.

A silver halide emulsion may contain additives such as an antifoggant and a stabilizer. Gelatin is useful as the binder for a silver halide emulsion, but other substances may also be employed.

Emulsion layers and other hydrophilic colloidal layers may be hardened, and may contain a plasticizer and a dispersion (latex) of a polymer which is soluble or sparingly soluble in water.

Emulsion layers of the silver halide light-sensitive material of the present invention each contain a color-forming coupler. Each of them may also contain a colored coupler for color compensation, a competitive coupler and a compound which can release, upon a coupling reaction with an oxidized developing agent, a photographically effective fragment such as a development accelerator, a bleaching accelerator, a developing agent, a silver halide solvent, a toning agent, a hardener, a foggant, an anti-foggant, a chemical sensitizer and a desensitizer.

The light-sensitive material of the invention may be provided with auxiliary layers such as a filter layer, an anti-halation layer and an anti-irradiation layer. These layers and/or silver halide emulsion layers each may contain a dye which can be removed therefrom or bleached out during development.

In the invention, silver halide emulsions described in Research Disclosure No. 308119 may also be employed.

Silver halide emulsions to be employed in the invention are subjected to physical ripening, chemical ripening and spectral sensitization. Additives to be used in these processes are described in Research Disclosure Nos. 17643, 18716 and 308119.

Additives may be added, for instance, by the dispersion method described in Research Disclosure No. RD308119XIV.

In the light-sensitive material of the invention, the order of layers may be either conventional or inverted. The light-sensitive material of the invention may be of unit structure. (For the layer order or the structure of a light-sensitive material, see Research Disclosure No. 308119VII-K).

As the support, use can be made of polyethylene-coated paper, polyethylene terephthalate films, baryta paper and cellulose triacetate films.

The present invention can be applied to color negative films for normal photography and cinematography, color reversal films for slide projection and telecasting, color paper, color positive films and color reversal paper.

The light-sensitive material of the present invention is, after exposure to light, processed by conventional methods described in Research Disclosure No. 17643, pp. 28-29, Research Disclosure No. 18716. p. 647 and Research Disclosure No. 308119, sec. XIX, whereby a dye image can be obtained.

The present invention will be described in more detail according to the following examples, which should not be construed as limiting the scope of the invention. In the following examples, the amounts of ingredients are expressed in terms of gram per square meter of a light-sensitive material, unless otherwise indicated. The amounts of silver halide and colloidal silver are converted into the amounts of silver. The amount of a sensitizing dye is expressed in terms of mol per mol of a silver halide contained in the same layer.

On a cellulose triacetate film support, layers of the following compositions were provided in sequence, whereby a multilayer color photographic light-sensitive material (Sample No. 101) was obtained.

First layer (anti-halation layer) Black colloidal silver 0.18 UV absorber (UV-1) 0.23 High-boiling solvent (Oil-1) 0.20 Gelatin 1.46 Second layer (intermediate layer) Gelatin 1.30 Third layer (low-speed red-sensitive layer) Silver iodobromide emulsion (average grain size: 0.27 µm, average silver iodide content: 7 mol%) 0.80 Sensitizing dye (I-34) 1.31 × 10⁻⁴ Sensitizing dye (I-6) 6.55 × 10⁻⁴ Sensitizing dye (III-11) 6.55 × 10⁻⁴ Cyan coupler (C-1) 0.60 Colored cyan coupler (CC-1) 0.10 DIR compound (D-25) 0.25 DIR compound (D-23) 0.004 High-boiling solvent (Oil-1) 0.50 Gelatin 0.90 Fourth layer (intermediate layer) Gelatin 1.00 Fifth layer (high-speed red-sensitive emulsion layer) Silver iodobromide emulsion (average grain size: 0.38 µm, average silver iodide content: 7 mol%) 1.00 Sensitizing dye (I-34) 0.18 × 10⁻⁴ Sensitizing dye (I-6) 2.16 × 10⁻⁴ Sensitizing dye (III-11) 2.16 × 10⁻⁴ Cyan coupler (C-1) 0.10 Colored cyan coupler (CC-1) 0.01 DIR compound (D-25) 0.015 DIR compound (D-23) 0.005 High-boiling solvent (Oil-1) 0.15 Gelatin 0.90 Sixth layer (intermediate layer) Anti-stain agent (SC-1) 0.10 High-boiling solvent (Oil-2) 0.10 Gelatin 1.00 Seventh layer (low-speed green-sensitive emulsion layer) Silver iodobromide emulsion (average grain size: 0.27 µm, average silver iodide content: 7 mol%) 0.80 Sensitizing dye (II-5) 8.5 × 10⁻⁵ Sensitizing dye (SD-1) 8.5 × 10⁻⁴ Magenta coupler (M-1) 0.53 Colored magenta coupler (CM-2) 0.09 DIR compound (D-32) 0.0025 DIR compound (D-23) 0.005 High-boiling solvent (Oil-2) 0.70 Gelatin 1.30 Eighth layer (high-speed green-sensitive emulsion layer) Silver iodobromide emulsion (average grain size: 0.38 µm, average silver iodide content: 7 mol%) 0.90 Sensitizing dye (SD-2) 3.5 × 10⁻⁴ Sensitizing dye (SD-3) 2.0 × 10⁻⁴ Magenta coupler (M-1) 0.17 Colored magenta coupler (CM-1) 0.06 DIR compound (D-32) 0.004 DIR compound (D-23) 0.002 High-boiling solvent (Oil-2) 0.40 Gelatin 0.80 Ninth layer (yellow filter layer) Yellow colloidal layer 0.10 Anti-stain agent (SC-1) 0.10 High-boiling solvent (Oil-2) 0.10 Gelatin 1.00 Tenth layer (low-speed blue-sensitive emulsion layer) Silver iodobromide emulsion (average grain size: 0.27 µm, average silver iodide content: 7 mol%) 0.50 Sensitizing dye (SD-4) 7.0 × 10⁻⁴ Yellow coupler (Y-1) 0.40 Yellow coupler (Y-2) 0.30 DIR compound (D-25) 0.01 High-boiling solvent (Oil-2) 0.10 Gelatin 0.90 Eleventh layer (high-speed blue-sensitive emulsion layer) Silver iodobromide emulsion (average grain size: 0.38 µm, average silver iodide content: 7 mol%) 0.65 Sensitizing dye (SD-4) 6.0 × 10⁻⁴ Yellow coupler (Y-1) 0.20 High-boiling solvent (Oil-2) 0.08 Gelatin 0.55 Twelfth layer (first protective layer) Silver iodobromide fine grain emulsion (average grain size: 0.08 µm) 0.40 UV absorber (UV-1) 0.07 UV absorber (UV-2) 0.10 High-boiling solvent (Oil-1) 0.07 High-boiling solvent (Oil-3) 0.07 Gelatin 0.60 Thirteenth layer (second protective layer) Alkaline-soluble matting agent (average grain size: 2 µm) 0.15 Polymethylmethacrylate (average grain size: 3 µm) 0.04 Lubricant (WAX-1) 0.04 Gelatin 0.60

Besides the above ingredients, coating aids Su-1 and Su-2, a viscosity controller, hardeners H-1 and H-2, a stabilizer ST-1 and anti-foggants AF-1 and AF-2 (two kinds AF-2 were employed. One had a molecular weight of 100,000 and the other had 1,100,000) were added.

Sample Nos. 102 to 106 were each prepared in substantially the same manner as in the preparation of Sample No. 101, except that the type and amount of the sensitizing dye and the DIR compound in the 3rd and 5th layers, as well as the type and amount of the DIR compound in the 7th and 8th layers were varied to those shown in Table 1.

Each of the so-prepared samples was examined for ISO sensitivity S and red densities D_N2, D_N16, D_R2 and D_R16. As the red filter, use was made of Wratten filter No. 26 (manufactured by Eastman Kodak Co., Ltd.). Using each sample, a color rendition chart (manufactured by Macbeth) and a red sweater were photographed. Then, each sample was processed according to the following procedure. Processing procedure (38°C) Color developing 3 min 10 sec Bleaching 6 min 30 sec Fixing 3 min 15 sec Rinsing 6 min 30 sec Stabilizing 3 min 15 sec Drying 1 min 30 sec

The processing liquids had the following compositions: 〈Color Developer〉 4-amino-3-methyl-N-ethyl-N-(β-hydroxyethyl) aniline sulfate 4.75 g Anhydrous·sodium sulfite 4.24 g Hydroxylamine 1/2 sulfate 2.0 g Anhydrous potassium carbonate 37.5 g Sodium bromide 1.3 g Trisodium nitrilotriacetate (monohydrate) 2.5 g Potassium hydroxide 1.0 g Water was added to make the total quantity 1 liter.
(pH=10.1) Bleacher Ferric (III) ammonium ethylenediaminetetraacetate 100.0 g Disodium ethylenediaminetetraacetate 10.0g Ammonium bromide 150.0 g Glacial acetic acid 10.0 ml Water was added to make the total quantity 1 liter, and pH was adjusted to 6.0 with aqueous ammonia. 〈Fixer〉 Ammonium thiosulfate 175.0 g Anhydrous sodium sulfite 8.5 g Sodium metasulfite 2.3 g Water was added to make the total quantity 1 liter, and pH was adjusted to 6.0 with aqueous ammonia. 〈Stabilizer〉 Formalin (37% aqueous solution) 1.5 ml Koniducks (Konica Corp) 7.5 ml Water was added to make the total quantity 1 liter.

Each of the so-obtained negative image was printed on color paper (Konica Color PC Paper Type SR) in such a manner that the gray color with an optical density of 0.7 of the rendition chart could be reproduced to have the same density. Each positive image was visually examined. The results of this examination and the red densities of each sample are summarized in Table 2. Sample No. D_N2-D_R2 D_N16-D_R16 Saturation of red Reproduction of red sweater 101 Comparative 0.07 -0.10 C C 102 Comparative 0.07 -0.05 B C 103 Comparative 0.15 0.10 C A 104 Invention 0.15 0.00 B A 105 Invention 0.13 0.02 A B 106 Invention 0.16 0.02 A A A: Excellent B: Fair C: Poor

As is evident from the results shown in Table 2, each of the samples of the invention could reproduce red with a high saturation, and could reproduce accurately the delicate shades of red.