Light-sensitive silver halide multi-layer color photographic material

Abstract: Disclosed is a light-sensitive silver halide multi-layer color photographic material having a light-sensitive silver halide emulsion layer combined with a non-diffusion coupler on a support, which comprises a light-sensitive silver halide emulsion layer farthest from the support which contains mono-dispersed silver halide grains comprising primarily (100) faces and having an average grain size of 0.2 to 0.8 µm. The light-sensitive silver halide multi-layer color photo­ graphic material of the present invention has stable perform­ ance against fluctuations in developing processing condi­ tions, has high sensitivity and low fogging.

Description: This invention relates to a light-sensitive silver halide multi-layer color photographic material, more particularly to a light-sensitive silver halide multi-layer color photographic material having excellent processing stability. In recent years, continuous processing of color papers is generally practised using an automatic developing machine. In this continuous processing, in order to keep constantly the components in the processing liquor, a supplemental system is employed. A concentrated-low-replenishment system is increasingly being employed for reducing the overflow liquors for reasons of economy and pollution. There are various problems which deteriorate the processing stability in the concentrated-low-replenishmental continuous processing using an automatic developing machine. For example, due to various factors such as the entrainment of a bleach-fixing liquor into the color developing liquor by "back-contamination", which is brought about, for example, by splashing within the processing machine and/or attachment on the conveying leader or belt, or fluctuation in the bromo ion density and pH in the color developing liquor due to an error in the amount of liquor replenished, and further increase in the chloro ion concentration in the color developing liquor according to the replenishment solution recovery system from the overflow liquor, fluctuation in sensitivity and graduation and increase of fog readily occurs. We have found that, in the case of color paper, the red-sensitive emulsion layer, which is the uppermost layer, is susceptible to fluctuation in the processing liquor conditions. Since increase of fog, change in sensitivity and gradation accompanied with the fluctuation in the developing processing conditions markedly lower the quality of the finished color print, it is desired to stabilize developing processing. For this purpose, it is known to incorporate various additives in the light-sensitive material. For example, such additives include nitrobenzimidazoles, mercaptothiazoles, benzotriazoles, nitrobenzotriazoles and mercaptotetrazoles as disclosed in U.S. Patents No. 3,954,474 and No. 3,982,947, and Japanese Patent Publication No. 28660/1977. It is also known to incorporate various additives in the processing liquors. A typical example is diethylene-triaminepentaacetic acid as disclosed in Japanese Patent Publication No. 16861/1979. However, the reduction of fluctuation in gradation and increase of fog is insufficient, the sensitivity of photographic performance is lowered and the storability of processing liquor is reduced. EP-A-0,070,182 discloses a silver halide light-sensitive color photographic material which comprises a support and a light-sensitive silver halide emulsion layer which contains a coupler. This layer contains monodispersed silver halide crystals which satisfy the relation: wherein and r = Σ n i r i /Σ n i in which r i represents the crystal size of individual silver halide crystals and n i represents the number of crystals. r is preferably from 0.3 to 1.5 µm. We have made investigations into color paper to improve processing stability of the uppermost red-sensitive emulsion layer. The present invention seeks to provide a light-sensitive silver halide color photographic material capable of providing stable performance against fluctuations in developing processing conditions and which is high in sensitivity and low in fogging. Accordingly the present invention provides a light-sensitive silver halide multi-layer color photographic paper material having a light-sensitive silver halide emulsion layer on a support wherein a light-sensitive silver halide emulsion layer which is positioned farthest from the support contains mono-dispersed silver halide grains and a non-diffusion coupler and is red-light sensitive, characterised in that said silver halide grains comprise primarily (100) faces, have an average grain size of 0.2 to 0.8 µm and have a value (hereinafter called CV) of the standard deviation S of the distribution of grain sizes (defined as shown below) divided by the average grain size r of 0.20 or less, preferably 0.15 or less, said silver halide is silver chlorobromide or silver chloride and said monodispersed silver halide grains satisfy the relation 5 ≦ K ≦ 500 wherein K is as defined below S = Σ( r - r i )² n i Σn i The average grain size means an average value of diameters of spheres when silver halide grains are spherically shaped or diameters of spherical images calculated to have the same area as the projected images of the shapes other than spheres, such as cubic bodies, when they are in the form of such shapes, and r is defined by the following formula when n i individual grains have a size of r i : r = Σn i r i Σn i The grain size may be measured according to various methods generally employed in this field of the art. Typical methods are described in Rubland "Grain size analytical method", A.S.T.M. Symposium On Light Microscopy, 1955, pp. 94-122 or "Theory of Photographic Process" by Mees and James, Third Edition, published by McMillan Co. (1966), Chapter 2. The grain size can be measured using the projected area or the approximate diameter. When the grains are substantially uniform in shape, the grain size distribution can be represented accurately as the diameter or the projected area. The silver halide grains comprising primarily (100) faces to be used in the light-sensitive silver halide emulsion layer which is positioned farthest from the support have an average grain size within the range of from 0.2 to 0.8 µm. If the average grain size is smaller than 0.2 µm, the gradation change and increase in fogging are greater with fluctuations in developing processing conditions. If the average grain size is greater than 0.8 µm, other problems, such as lowering of progress of development and, particularly in the case of color paper, worsening in color separation through increase in inherent sensitivity occur. The average grain size is preferably from 0.25 to 0.6 µm. It is preferred that the grain of the mono-dispersed silver halide emulsion is a normal crystal grain. The silver halide grains comprising primarily (100) faces are preferably cubic grains and/or tetradecahedral grains. The silver halide grains such that 5 ≦ K ≦ 500 wherein K = {intensity of diffracted ray attributable to (200) face}/{intensity of diffracted ray attributable to (222) face}, which is measured according to the X-ray diffraction analytical method as described in Japanese Provisional Patent Publication No. 29243/1984 and "Bulletin of the Society of Scientific Photography of Japan, No. 13, Dec., 1963". Such mono-dispersed silver halide grains preferably constitute at least 50% by weight (preferably at least 75% by weight) of the total silver halide grains contained in the light-sensitive silver halide emulsion layer which is positioned farthest from the support. The silver halide emulsion containing mono-dispersed silver halide grains may for example, be prepared using the method disclosed in Japanese Provisional Patent Publication No. 48521/1979, wherein an aqueous potassium chlorobromide-gelatin solution and an aqueous ammoniacal silver nitrate solution are added to an aqueous gelatin solution containing silver halide seed grains, changing the addition rate as a function of time. By suitable choice of the time function for addition rate, pAg and temperature, a highly mono-dispersed silver halide emulsion can be obtained. The silver halide grains may be uniform from the inner portion to the outer portion or have a structure in which the inner portion and the outer portion are different. More specifically, the mono-dispersed emulsion can be prepared by the following method. To prepare silver bromide and silver iodobromide crystals for light-sensitive photographic material, a silver salt aqueous solution and a halide salt aqueous solution can be added together in the presence of a protective colloid and reacted (in a double jet method) to grow seed crystals. Each of the above two aqueous solutions can be added at an addition speed of from Q (mole/min), represented by the following formula, to not less than 50% of Q. wherein x is a grain size of the growing crystals (µm), m o is the amount (mole) of seed crystals initially added, m is the total amount (mole) of aqueous silver salt solution added, and y is such that: y = 10 {fa(I) + fb(pAg) + fc(CNH 3 ) + fd(r, x )} wherein fa(I) = a₀ + a₁I, fb(pAg) = b₀ + b₁(pAg) + b₂(pAg)² + b₃(pAg)³ + b₄(pAg)⁴ + b₅(pAg)⁵, fc(CNH₃) = c₁ CNH₃ + c₀ + c₂ , fd(r, x ) = d₀ + d₁(r- x +0.5) + d₂(r- x +0.5)² + d₃log x . In the above formulae, I is the iodine content of silver iodobromide (mole percent), pAg is the logarithm of the silver ion concentration in the reaction solution, CNH₃ is the concentration of ammonia (mole/l) in the reaction solution, and r is the average distance (µm) between grains of growing crystals a₀, a₁, b₀, b₁, b₂, b₃, b₄, b₅, c₀, c₁, c₂, d₀, d₁, d₂ and d₃ are the numerals shown in the following table. A conventional double jet method may also, of course, be used. The silver halide grains may either be the type which forms latent images primarily on their surfaces or of the type which forms latent images within the inner portion thereof. The silver halide composition in the light-sensitive silver halide emulsion layer which is positioned farthest from the support comprises silver chloride or silver chlorobromide; particularly preferred is a silver chlorobromide containing 25 mole or more of silver bromide for a cclor paper. The layer structure may take any desired form. Preferably the emulsion layer which is positioned farthest from the support comprises at least 50% by weight (preferably 75% by weight or more) of the mono-dispersed silver halide grains having an average grain size of 0.2 to 0.8 µm comprising primarily (100) faces relative to the total amount of silver halide grains contained in the layer. It is preferred to use a multi-layer color paper in which a blue-sensitive silver halide emulsion layer, a green-sensitive silver halide emulsion layer and a red-sensitive silver halide emulsion layer are provided in order nearer to the support. The support is not particularly limited, but is preferably baryta paper, polyethylene-coated paper, polypropylene synthetic paper, glass paper, cellulose acetate, cellulose nitrate, polyvinyl acetal, polypropylene, polyester film, such as polyethylene terephthalate, or polystyrene. Particularly preferred is a polyethylenecoated paper or a polypropylene synthetic paper. These supports may suitably be chosen depending on the intended use of the light-sensitive material. The supports may be applied with subbing treatments, if desired. For the non-diffusion coupler it is possible to use those conventionally used in this field of the art. It is general practice to use a cyan coupler when the emulsion layer is red-sensitive, a magenta coupler when it is green-sensitive and a yellow coupler when it is blue-sensitive. An open-chain ketomethylene type coupler may be used as the yellow coupler. Benzoylacetanilide type compounds and pivaloylacetanilide type compounds are particularly useful. A pyrazolone type compound, indazolone type compound or cyanoacetyl type compound may be used as the magenta coupler and a phenol type compound or naphthol type compound may be used as the cyan coupler. The light-sensitive silver halide emulsion layer which is positioned farthest from the support is red-sensitive, so that the non-diffusion coupler contained in said layer is a cyan coupler. The non-diffusion coupler is preferably a phenol type cyan coupler, most preferably a cyan coupler of the formula (I): wherein R₁ represents an aryl group, a cycloalkyl group or a heterocyclic group; R₂ represents an alkyl group or a phenyl group; R₃ represents hydrogen, a halogen, an alkyl group or an alkoxy group; Z₁ represents hydrogen, a halogen or a group eliminatable through a reaction with an oxidized product of an aromatic primary amine type color developing agent. The aryl group represented by R₁ is, for example, a naphthyl group and is preferably a phenyl group. The heterocyclic group represented by R₁ is, for example, a pyridyl group or a furan group. The cycloalkyl group represented by R₁ is, for example, a cyclopropyl group or a cyclohexyl group. These R₁ groups may have a single or a plurality of substituents. Typical examples of substituents for the phenyl group include halogen (e.g. fluorine, chlorine, or bromine), an alkyl group (e.g. a methyl group, an ethyl group, a propyl group, a butyl group, or a dodecyl group), a hydroxyl group, a cyano group, a nitro group, an alkoxy group (e.g. a methoxy group, or an ethoxy group), an alkylsulfonamide group (e.g. a methylsulfonamide group or an octylsulfonamide group), an arylsulfonamide group (e.g. a phenylsulfonamide group, or a naphthylsulfonamide group), an alkylsulfamoyl group (e.g. a butylsulfamoyl group), an arylsulfamoyl group (e.g. a phenylsulfamoyl group), an alkoxycarbonyl group (e.g. a methyloxycarbonyl group), an aryloxycarbonyl group (e.g. a phenyloxycarbonyl group), an aminosulfonamide group, an acylamino group, a carbamoyl group, a sulfonyl group, a sulfinyl group, a sulfoxy group, a sulfo group, an aryloxy group, an alkoxy group, a carboxyl group, an alkylcarbonyl group, an arylcarbonyl group or an aminocarbonyl group. Two or more kinds of these substituents may be present on the phenyl group. R₁ preferably represents a phenyl group or a phenyl group having one or two or more substituents which are a halogen, an alkylsulfonamide group, an arylsulfonamide group, an alkylsulfamoyl group, an arylsulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, an alkylcarbonyl group, an arylcarbonyl group or a cyano group. The alkyl group represented by R₂ may be either straight or branched, for example a methyl group, an ethyl group, a propyl group, a butyl group or an octyl group. Typical examples of the cyan couplers of formula (I) are: The coupler of formula (I) may be used either alone or in combination with other cyan couplers. When a cyan coupler of formula (I) is used, the effect of the present invention can be further enhanced and the color restorability in the bleach-fixing processing can be improved to increase overall processing stability. The cyan coupler of formula (I) can be incorporated in the emulsion according to a conventional method. The silver halide grains used in the present invention can be applied using a chemical sensitizing method. For example, chemical sensitization can be achieved by using, singly or in combination, chemical sensitizers such as active gelatin; noble metal sensitizers such as water-soluble gold salts, water-soluble platinum salts, water-soluble palladium salts, water-soluble rhodium salts, and water-soluble iridium salts; sulfur sensitizers; selenium sensitizers; or reducing sensitizers such as a polyamine or stannous chloride. The emulsion containing silver halide grains can be optically sensitized to a desired wavelength region. The method for optical sensitization of the silver halide emulsion is not limited; optical sensitizers, for example, cyanine dyes such as zeromethyne dyes, monomethyne dyes, dimethyne dyes and trimethyne dyes or melocyanine dyes may be used either alone or in combination (e.g. color super sensitization) to effect optical sensitization. These techniques are disclosed, for example, in U.S. Patents No. 2,688,545, No. 2,912,329, No. 3,397,060, No. 3,615,635 and No. 3,628,964; U.K. Patents No. 1,195,302, No. 1,242,588 and No. 1,293,862; German Patent (OLS) No. 2,030,325 and No. 2,121,780; and Japanese Patent Publications No. 4936/1968 and No. 14030/1969. The sensitizers may be chosen as desired depending on the purpose and use of the light-sensitive silver halide photographic material, such as the wavelength region to be sensitized and the sensitivity desired. The silver halide emulsion can contain various additives conventionally used, depending on its purpose. These additives include, for example, stabilizers or antifoggants such as azaindenes, triazoles, tetrazoles, imidazolium salts, tetrazolium salts or polyhydroxy compounds; film hardeners such as aldehyde type, aziridine type, inoxazole type, vinyl sulfone type, acryloyl type, adipodiimide type, maleimide type, methanesulfonic acid ester type or triazine type hardeners; developing accelerators such as benzyl alcohol or polyoxyethylene type compounds; image stabilizers such as couromane type, cumarane type, bisphenol type or phosphite type stabilizers, lubricants such as wax, glycerides of higher fatty acids, or higher alcohol esters of higher fatty acids. Surfactants, for coating aids, agents for improving penetrability for processing liquors, defoaming agents or various materials for controlling various physical properties of the light-sensitive material, or anionic, cationic, nonionic or amphoteric surfactants can be used. Antistatic agents, such as diacetyl cellulose, styreneperfluoroalkyl sodium maleate copolymer or alkali salts of the reaction product of styrene-maleic anhydride copolymer with p-aminobenzenesulfonic acid may be effective. A matting agent, such as polymethylmethacrylate, polystyrene or alkali soluble polymers may be used. Use of colloidal silicon oxide may, for example, be possible. For a latex to be added for improvement of film properties, there may, for example, be used copolymers of acrylates or vinyl esters with monomers having other ethylenic groups. A gelatin plasticizer, such as glycerine and glycolic compounds, and a thickener, such as styrene-sodium maleate copolymer or alkylvinyl ether-maleic acid copolymer may also be used. The light-sensitive photographic material can be developed according to a known color developing method conventionally used after exposure. In the reversal method, developing is carried out with a black-and-white negative developing solution, subsequently white color exposure is given or processing in a bath containing a fogging agent is conducted, followed by color developing with an alkali developing solution containing a color developing agent. All processing methods are applicable. For example, it is possible to use a system in which, after color developing, bleach-fixing processing is performed, and if desired, further washing with water and stabilizing processing, or after color developing, bleaching and fixing are performed separately, and, if desired, further washing with water and stabilizing processing. This invention is further described in detail in the following Examples. Example 1 Using the double jet method as described in Japanese Provisional Patent Publication No. 48521/1979 and by controlling the pAg, an octahedral mono-dispersed emulsion (called Emulsion A) and a cubic mono-dispersed emulsion (called Emulsion B) and three kinds of tetradecahedral mono-dispersed emulsion with different ratios of (100) face and (111) face (called Emulsions C, D, and E) of silver chlorobromide (each containing 80 mole% of silver bromide) with an average grain size of 0.4 µm were prepared. According to a known method, a sulfur sensitizer, a red-sensitive sensitizing dye and a stabilizer were added to prepare a red-sensitive silver chlorobromide emulsion. The following layers were coated successively on a paper support with a resin coating to prepare a light-sensitive silver halide multi-layer photographic material (the amount of each material used in the respective layer is shown as weight (mg) per dm²): (1) Blue-sensitive silver halide emulsion layer containing a yellow coupler A (7.8 mg) shown below, a blue-sensitive silver chlorobromide (octahedral mono-dispersed (S/ r = 0.12) emulsion having average grain size 0.8 µm which was prepared by the same manner as mentioned above, 4.0 mg calculated silver) and 20 mg of gelatin; (2) Intermediate layer containing 0.2 mg of dioctylhydroquinone and 10 mg of gelatin; (3) Green-sensitive silver halide emulsion layer containing a magenta coupler B (4.2 mg) shown below, a green-sensitive silver chlorobromide emulsion (octahedral mono-dispersed (S/ r = 0.12) emulsion having average grain size 0.5 µm which was prepared by the same manner as mentioned above, 3.7 mg calculated silver) and 20 mg of gelatin; (4) Intermediate layer containing 0.3 mg of dioctylhydroquinone and 15 mg of gelatin; (5) Red-sensitive silver halide emulsion layer containing a cyan coupler C (3.2 mg) shown below, a red-sensitive silver chlorobromide emulsion (average grain size 0.35 µm, 3.0 mg calculated silver) and 15 mg of gelatin; (6) Gelatin protective layer containing 10 mg of gelatin. Yellow coupler A: Magenta coupler B: Cyan coupler C: 5 emulsions were prepared using Emulsions A to E to prepare Samples No. 1 to No. 5. The five coated samples were exposed to white light through an optical wedge by means of a sensitometer (KS-7 (Trade Mark) Model produced by Konishiroku Photo Industry Co.), and then processing was applied following the processing steps shown below. [Color developing solution No. 1] made up to one liter with addition of pure water (pH = 10.2). [Bleach-fixing solution No. 1] made up to one liter with addition of pure water (pH = 7.2). In carrying out developing with color developing solution No. 2, the compounds as shown in Table 1 were further added to the color developing solution No. 1 for comparative development. Each of the samples obtained by processing was measured by means of an optical densitometer (PDA-60 (Trade Mark) Model, produced by Konishiroku Photo Industry Co.) to determine the gamma value for densities from 0.8 to 1.8. The results are shown in Table 2 below. As seen from Table 2, the red-sensitive layer of the uppermost layer is most influenced by an increase of potassium bromide, and fluctuation of the gamma value of the red-sensitive layer is improved to great extent in Samples No. 12, No. 13, No. 14 and No. 15 according to the present invention. Particularly, in Samples No. 13 to No. 15, fluctuation of the gamma value of the red-sensitive layer is low, these samples have excellent photographic properties. Example 2 The same samples as in Example 1 were exposed to light and processed in the same manner as in Example 1, except that the color developing liquors as shown in Table 3 were employed. For the samples obtained, fog and gamma value of the red-sensitive layer were measured similarly as in Example 1. The results are shown in Table 4. As seen from Table 4, even in the case of increase of pH and contamination of bleach-fixing liquor, Samples No. 12 to No. 15 according to the present invention show excellent processing stability. Particularly, in Samples No. 13 to No. 15, fluctuation of gamma values is low and fog is low, these samples have excellent photographic properties. Example 3 According to the same method as in Example 1, tetradecahedral mono-dispersed (s/ r = 0.10) emulsions of silver chlorobromide (containing 70 mole% of silver bromide) with average grain sizes of 0.15 µm, 0.3 µm, 0.6 µm and 0.9 µm (Emulsions F, G, H and I), and a tetradecahedral poly-dispersed (s/ r = 0.28) emulsion (which was prepared by double-jet method without controlling addition speed) with average grain size of 0.3 µm (Emulsion J) were prepared and red-sensitive silver chlorobromide emulsions were obtained and light-sensitive silver halide multi-layer color photographic materials were prepared in a similar manner to Example 1. Light exposure, processing and measurement were conducted in the same manner as in Example 1. The results of the red-sensitive layers obtained are shown in Table 5. As seen from Table 5, the samples of this invention No. 32 and No. 33 have low fluctuation of gamma values, but the sample No. 31, outside the scope of the present invention, and sample No. 35 have great fluctuation of gamma values. In sample No. 34, gamma value is low even in comparative processing due to deterioration in developing characteristic, and color turbidity also occurred due to increase in inherent sensitivity. Thus, it is not suitable for practical applications. Example 4 By use of the Emulsions B and D prepared in Example 1, samples were prepared, exposed, processed and measured in a similar manner to Example 1, by using the cyan couplers shown in Table 6. The results obtained are shown in Table 6. C: Cyan couplers employed in Example 1 As is apparent from Table 6, all the samples have good properties. Samples No. 42 to No. 44 and No. 46 to No. 48 have superior properties using cyan couplers of formula [I] as compared with Samples No. 41 and No. 45 which used comparative cyan coupler C.

Claims: A light-sensitive silver halide multi-layer color photographic paper material having a light-sensitive silver halide emulsion layer on a support wherein a light sensitive silver halide emulsion layer which is positioned farthest from the support contains mono-dispersed silver halide grains and a non-diffusion coupler and is red-light-sensitive characterized in that said silver halide grains comprise primarily (100) faces, have an average grain size of 0.2 to 0.8 µm and have a value of the standard deviation S of the distribution of grain sizes divided by the average grain size r of 0.20 or less, said silver halide is silver chlorobromide or silver chloride and said mono-dispersed silver halide grains satisfy the relation 5 ≦ K ≦ 500 wherein K = {intensity of diffracted ray attributable to (200) face}/{intensity of diffracted ray attributable to (222) face}, measured according to the X-ray diffraction analytical method. A light-sensitive silver halide multi-layer color photographic material according to claim 1 wherein said mono-dispersed silver halide grains have a value of the standard deviation S of the distribution of grain sizes divided by the average grain size r of 0.15 or less. A light-sensitive silver halide multi-layer color photographic material according to claim 1 or 2 wherein the average grain size of said mono-dispersed silver halide grains is from 0.25 to 0.64µm. A light-sensitive silver halide multi-layer color photographic material according to any one of claims 1 to 3 wherein the said mono-dispersed silver halide grains are cubic grains and/or tetradecahedral grains. A light-sensitive silver halide multi-layer color photographic material according to any one of claims 1 to 4 wherein said mono-dispersed silver halide grains constitute at least 50% by weight of the total silver halide grains contained in the light-sensitive silver halide emulsion layer which is positioned farthest from the support. A light-sensitive silver halide multi-layer color photographic material according to claim 5, wherein said mono-dispersed silver halide grains constitute at least 75% by weight of the total silver halide grains contained in the light-sensitive silver halide emulsion layer which is positioned farthest from the support. A light-sensitive silver halide multi-layer color photographic material according to any one of claims 1 to 6 wherein said non-diffusion coupler is a cyan coupler. A light-sensitive silver halide multi-layer color photographic material according to claim 7 wherein said cyan coupler is a compound of formula: wherein R₁ represents an aryl group, a cycloalkyl group or a heterocyclic group; R₂ represents an alkyl group or a phenyl group; R₃ represents hydrogen, a halogen, an alkyl group or an alkoxy group; Z₁ represents a hydrogen atom, a halogen atom or an eliminable group through the reaction with the oxidized product of an aromatic primary amine type color developing agent.

Inventors: KOMORITA KAZUO, MIYOSHI MASANOBU, ONODERA KAORU, KOMORITA, KAZUO, MIYOSHI, MASANOBU, ONODERA, KAORU
Applicants: KONISHIROKU PHOTO IND, KONICA CORPORATION
Application year: 1985
Main classification: G03C7
IPC codes: G03C1, G03C7