EP0468781A1

EP0468781A1 - Method of processing light sensitive silver halide color photographic material

Info

Publication number: EP0468781A1
Application number: EP91306778A
Authority: EP
Inventors: Wataru Satake; Shinasku Nagaoka; Shigeharu Koboshi
Original assignee: Konica Minolta Inc
Current assignee: Konica Minolta Inc
Priority date: 1990-07-25
Filing date: 1991-07-25
Publication date: 1992-01-29
Also published as: JP2955881B2; JPH0481848A

Abstract

There is disclosed a method for processing a silver halide color photographic material which is improved in processing stability, particularly when the photographic materials are intermittently processed with the use of a processing machine, wherein the photographic material is developed in a color developing solution containing a chloride in a concentration of not less than 6 x 10⁻² mol/lit. and a buffering agent having pKa value of not less than 10.5 at a temperature of not lower than 38 °C.

Description

FIELD OF THE INVENTION

The present invention relates to a method of processing light-sensitive silver halide color photographic material. More particularly it relates to a technique for stabilizing photographic performances in color processing in which the amount of replenishment has been decreased.

BACKGROUND OF THE INVENTION

Light-sensitive silver halide color photographic materials are processed basically through two steps of color development and desilvering. The desilvering is comprised of the steps of bleaching and fixing or the step of bleach-fixing. Besides these, rinsing and stabilizing are added as additional processing steps.
In color development, an exposed silver halide is reduced to silver and at the same time an oxidized aromatic primary amine developing agent reacts with a coupler to form a dye. In this course of reaction, halide ions produced as a result of the reduction of silver halide dissolve out to a developing solution and accumulate therein. Besides, components such as a restrainer contained in a light-sensitive silver halide photographic material also dissolve out to a color developing solution and accumulate therein. In the step of desilvering, the silver produced as a result of development is bleached by an oxidizing agent and then all silver salts are removed as soluble silver salts by a fixing agent from the light-sensitive photographic material. Monobath bleach-fixing is also known, by which both the bleaching step and fixing step can be carried out simultaneously.
In the color developing solution, development restraining substances accumulate as a result of the processing of light-sensitive photographic materials as stated above. On the other hand, a color developing agent and benzyl alcohol are consumed, or accumulated in a light-sensitive photographic material so as to be carried over, so that the concentration of these components becomes lower. The pH also becomes lower because of hydrogen ions released as a result of development reaction.
Hence, in the processing that continuously processes a large quantity of light-sensitive silver halide photographic materials by means of an automatic processor or the like, it is necessary to take a means for maintaining the components in a color developing solution within a given range of concentration so that performances after finish of development can be prevented from being changed because of changes in the concentration of components. As a means therefor, it is usual to feed a replenishing solution that supplies components having run short and dilutes unnecessary increased components. The feeding of this replenishing solution necessarily brings about an overflow in a large quantity, which is discarded. Hence, this method raises great problems of economical disadvantages and environmental pollutions. Thus, in recent years, a method in which developing solutions are regenerated by the ion-exchange resin process or by electrodialysis, a concentrated low-replenishing method and also a method in which a regenerant is added to an overflowing solution so that it can be again used as a replenishing solution have been proposed and put into practical use.
Developing solutions are regenerated by removing unwanted accumulated components, i.e., matters dissolved out from light-sensitive materials, and supplying the components having run short. This method (including the ion-exchange resin process and the electrodialysis), however, has a disadvantage such that the development processing performances of light-sensitive materials may be damaged unless the quantities of components in a developing solution are determined by chemical analysis so as to be made constant, and requires a complicated management. Hence, it is almost impossible for this method to be employed in small-scale finishing laboratories or mini-labs having no particular skills. This method also has the disadvantage that it requires a very high initial cost.
Moreover, the method in which a regenerant is added to an overflowing solution so that it can be again used as a replenishing solution, though requiring no particular skills, has the disadvantage that it requires a space for stock tanks, etc. or is cumbersome for the finishing laboratories to handle. Hence, it is very difficult for this method also to be employed in mini-labs or the like. On the other hand, the concentrated low-replenishing method can be said to be very suited for small-scale finishing laboratories (or mini-labs) where processing is carried out in a small quantity, since this method requires no particular additional apparatus and processing can be managed with ease.
The concentrated low-replenishing method, however, also has some problems. That is, it has the problems that a decrease in maximum density, a decrease in gamma and a decrease in sensitivity may become extraordinary with an increase in the accumulation of organic restrainers dissolved out of light-sensitive materials and the accumulation of hydrogen ions that are released as a result of development reaction.
Such problems are particularly remarkable in the small-scale finishing laboratories in which a relatively small quantity of light-sensitive materials are processed in a discontinuous manner.
As a countermeasure therefor, there is a means of raising processing temperature. This means can solve the above problems, but on the other hand causes other problems such that fog frequently occurs in unexposed areas and no stable photographic performance can be obtained.
Under such circumstances, the present inventors made various studies, and have discovered that to our surprise these problems can be all settled when a color developing solution containing a chloride added in a given concentration and a buffering agent with a pKa of not less than 10.5 is used and the processing is carried out at a temperature of not lower than 38°C. They have thus accomplished the present invention.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a technique for stabilizing photographic performances when light-sensitive silver halide color photographic material are processed by the low-replenishing method, in particular, when they are processed in a small processing quantity in a discontinuous manner, stated specifically, to provide a method of processing a light-sensitive silver halide color photographic material, that can obtain a stable color-forming performance, i.e., maximum density, can give less fog density and also may cause less variations of gradation.
The above object of the present invention can be achieved by a method of processing a light-sensitive silver halide color photographic material, comprising processing said light-sensitive silver halide color photographic material by the use of a color developing solution containing at least a chloride in a concentration of not less than 6 x 10⁻² mol/lit. and a buffering agent with a pKa of not less than 10.5, and at a temperature of not lower than 38°C.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the present invention can be exemplified by the following embodiments (1) to (4), according to which the object of the present invention can be more highly achieved.

(1) Chloride ion concentration in the color developing solution is set within the range of 8 x 10⁻² mol/lit. to 2.0 x 10⁻¹ mol/lit.
(2) The pKa of the buffering agent is set within the range of 11.0 to 13.0.
(3) Phosphoric acid is used as the buffering agent.
(4) Temperature for color development is set within the range of 38.3°C to 43.0°C.

The present invention will be described below in more detail.
The chloride incorporated in the color developing solution of the present invention may include chlorides of alkali metals, as exemplified by potassium chloride, sodium chloride and lithium chloride, any of which can be preferably used. It may be contained in an amount, as described above, of not less than 6 x 10⁻² mol/lit., and preferably in an amount corresponding to the range of 8 x 10⁻² mol/lit. ≦ [Cl⁻] ≦ 2.0 x 10⁻¹ mol/lit.
The buffering agent referred to in the present invention means a substance having a resistance to changes in the concentration of hydrogen ions in the solution. The buffering capacity of buffering agents is commonly in the range of ± 1 of the acid dissociation constant pKa of that substance, and their maximum value is at a point of pH = pKa.
Among these buffering agents, an agent with a pKa of not less than 10.5 is added to the color developing solution. The object of the present invention can be thereby well achieved. They can also be used in combination of two or more kinds.
The buffering agent preferably usable in the present invention may include the following buffering agents having a pKa value of 10.5 or more. These buffering agents may be used in the form of salts such as a sodium salt and a potassium salt.
The buffering agent incorporated in the color developing solution of the present invention has a pKa of not less than 10.5 as stated above. It may preferably be those with a pKa of 11.0 to 13.0, and most preferably be phosphoric acid.
In the color developing solution of the present invention, hydroxylamine derivatives, as disclosed in Japanese Patent Publications Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication(s)) No- 146043/1988, No. 146042/1988, No. 146041/1988, No. 146040/1988, No. 135938/1988 and No. 118748/1988, hydroximic acids as disclosed in Japanese Patent O.P.I. Publication No. 62639/1989, hydrazines, hydrazides, phenols, α-hydroxyketones, α-aminoketones, saccharides, monoamines, diamines, quaternary ammonium salts, nitroxy radicals, alcohols, oximes, diamide compounds, condensed ring type amines are preferably used as organic preservatives in place of hydroxylamines conventionally used as preservatives
In particular, incorporation of a compound represented by the following formula A or B brings about a preferable result for rapid processing and for a decrease in bluing, and also a good result with regard to the deposition of tar on the wall surface of a color developing solution tank. It can also be effective from other aspects, and hence can be said to be one of more preferred embodiments of the present invention.

Formula A

In the formula A, R₁ and R₂ each represent a hydrogen atom, an alkyl group, an aryl group, R′-CO-, provided that both are not hydrogen atoms at the same time. The alkyl groups represented by R₁ and R₂ may be the same or different, and each may preferably be an alkyl group having 1 to 3 carbon atoms.
R′ represents an alkoxyl group, an alkyl group or an aryl group.
The alkyl groups represented by R₁, R₂ and R′ may include those having a substituent. R₁ and R₂ may combine each other to form a ring. For example, they may form a heterocyclic ring such as piperidine, pyridine, triazine or morpholine.
Specific compounds of the hydroxylamine compound represented by the formula A are disclosed in U.S. Patents No. 3,287,125, No. 3,293,304 and No. 3,287,124. Preferred specific exemplary compounds are shown below.

Formula B

In the formula B, R₃, R₄ and R₅ each represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group, R₆ represents a hydroxyl group, a hydroxylamino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted carbamoyl group, or an amino group. The heterocyclic group is a ring of 5 to 6 members, constituted of e.g., C, H, O, N and S, and may be saturated or unsaturated. R₇ represents represents a divalent group selected from -CO-, -SO₂- and -C(=NH)-, and n is an integer of 0 or 1. In particular, when n is 0, R₆ represents a group selected from an alkyl group, an aryl group and a heterocyclic ring. R₅ and R₆ may combine to form a heterocyclic ring.
In the formula B, R₃, R₄ and R₅ may each preferably be a hydrogen atom or an alkyl groups having 1 to 10 carbon atoms. In particular, R₃ and R₄ are most preferably hydrogen atoms.
In the formula B, R₆ may preferably be an alkyl group, an aryl group, a carbamoyl group or an amino group. In particular, it is preferably an alkyl group or a substituted alkyl group. Here, preferred substituents of the alkyl group are a carboxyl group, a sulfo group, a nitro group, an amino group, a phosphono group, etc.
Examples of the compound represented by the formula B are shown below.
Average molecular weight: about 4,000
These compounds represented by the formula A or B are usually used in the form of free amines, hydrochlorides, sulfates, p-toluenesulfonates, oxalates, phosphates, acetates or the like.
The compound represented by the above formula A or B may be contained in the color developing solution in a concentration of usually 0.2 g/lit. to 50 g/lit., preferably 0.5 g/lit. to 30 g/lit., and more preferably 1 g/lit. to 15 g/lit.
The compound represented by the formula A or B can be used in combination with a conventionally used hydroxylamine and the organic preservative previously described. In view of developability, it is preferred not to use the hydroxylamine.
In the color developing solution of the present invention, incorporation of a compound represented by the following formula C or D brings about an improvement effect against air oxidation of the color developing solution, and also has little ill influences even when included into a bleach-fixing solution. Thus, these compounds are preferably used. Formula C
In the formula C, R₈ represents a hydroxyalkyl group having 2 to 6 carbon atoms, R₉ and R₁₀ each represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group having 2 to 6 carbon atoms, a benzyl group or a group represented by the formula:

wherein n′ represents an integer of 1 to 6, X and Y each represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a hydroxyalkyl group having 2 to 6 carbon atoms.
Preferred examples of the compound represented by the formula C are as follows:

C-1: Ethanolamine
C-2: Diethanolamine
C-3: Triethanolamine
C-4: Di-isopropaanolamine
C-5: 2-Methylaminoethanol
C-6: 2-Ethylaminoethanol
C-7: 2-Dimethylaminoethanol
C-8: 2-Diethylaminoethanol
C-9: 1-Diethylamino-2-propanol
C-10: 3-Diethylamino-1-propanol
C-11: 3-Dimethylamino-1-propanol
C-12: Isopropyaminoethanol
C-13: 3-Amino-1-propanol
C-14: 2-Amino-2-methyl-1,3-propanediol
C-15: Ethylenediaminetetraisopropanol
C-16: Benzyldiethanolamine
C-17: 2-Amino-2-(hydroxymethyl)-1,3-propanediol

Formula D

H-(-O-A-)_n˝-(-O-B-)_m-OH
In the formula D, A and B each represents a straight-chain or branched alkylene group, and n˝ and m each represent an integer of 0 to 100, provided that n˝ and m are not 0 at the same time.
Preferred examples of the compound represented by the formula D are as follows:

D-1 HO-CH₂CH₂-OH

D-5 HO-CH₂CH₂CH₂-OH

D-11 HO-CH₂CH₂CH₂CH₂-OH

D-18 HO-CH₂CH₂-O-CH₂CH₂-OH

D-24 HO-CH₂CH₂CH₂-O-CH₂CH₂-OH

D-25 HO-CH₂CH₂CH₂-O-CH₂CH₂CH₂-OH
The compound represented by the formula C or D may preferably be used in an amount ranging from 1 g to 100, and more preferably 2 g to 50 g, per liter of the color developing solution from the view point of preventing air oxidation.
The color developing agent used in the color developing solution of the present invention may preferably be a p-phenylenediamine compound having a water-soluble group. Here, at least one water-soluble group is present on the amino group or benzene ring of the p-phenylenediamine compound. A specific water-soluble group may preferably include;

(CH₂)_n-CH₂OH,
(CH₂)_m-NHSO₂-(CH₂)_n-CH₃,
(CH₂)_m-O-(CH₂)n-CH₃,
(CH₂CH₂O)_nC_2m+1
wherein m and n each represent an integer of 0 or more;

Specific exemplary compounds of the color developing agent preferably used in the present invention are shown below.

(Exemplary Color Developing Agents)

Of the color developing agents exemplified above, those preferably used in the present invention are the compounds represented by the compound Nos. (DA-1), (DA-2), (DA-3), (DA-4), (DA-6), (DA-7) and (DA-15). Particularly preferred is the compound No. (DA-1).
The color developing agents described above are usually used in the form of salts such as hydrochlorides, sulfates and p-toluenesulfonates.
In the present invention, the preferably usable p-phenylenediamine compound having the water-soluble group is required to be in an amount of not less than 4.5 x 10⁻³ mol, and preferably in an amount ranging from 6.5 x 10⁻³ mol to 3.4 x 10⁻² mol, per liter of the color developing solution.
In addition to the components described above, the color developing solution used in the present invention may contain the following developing solution components.
Inorganic or organic antifoggants can be optionally added. A development accelerator can also be optionally used.
The development accelerator may include various pyridinium compounds as typically disclosed in U.S. Patents No. 2,648,604 and No. 3,671,247 and Japanese Patent Examined Publication No. 9503/1969, and other cationic compounds; cationic dyes such as phenosafranine; neutral salts such as thallium nitrate; polyethylene glycol and derivatives thereof as disclosed in U.S. Patents No. 2,533,990, No. 2,531,832, No. 2,950,970 and No. 2,577,127 and Japanese Patent Examined Publication No 9504/1969; nonionic compounds such as polythioethers; phenethyl alcohol as disclosed in U.S. Patent No. 2,304,925; and besides acetylene glycol, methyl ethyl ketone, dichlorohexanone, thioethers, pyridine, ammonia, hydrazine, and amines.
Benzyl alcohol is not preferably used in the present invention. With regard to sparingly soluble organic solvents as typified by the above phenethyl alcohol, it is preferred for them not to be used in order to efficiently achieve the stated object of the present invention.
Use of the benzyl alcohol tends to result in the formation of tar when the color developing solution is used over a long period of time, in particular, in running processing carried out according to the low-replenishing method. The tar thus formed may adhere to paper light-sensitive materials being processed, even to cause a serious trouble that their commercial values are seriously damaged.
The sparingly soluble organic solvents have a poor solubility in water. Hence, not only they make it necessary to take the trouble to use a stirrer to prepare the color developing solution itself, but also even the use of such a stirrer can not avoid a limit in the effect of accelerating development, because of its poorness in solubility.
Moreover, the sparingly soluble organic solvents have a large value for the burden of environmental pollution, as exemplified by the biological oxygen demand (BOD), and can not be thrown away in drainage or rivers. Thus, much labor and cost are required for the disposal of waste liquor. Because of such problems, not only benzyl alcohol but also other sparingly soluble organic solvents should preferably be used in quantities as small as possible or be not used.
The color developing solution of the present invention may preferably contain a triazinylstilbene fluorescent brightening agent.
The triazinylstilbene fluorescent brightening agent may include those represented by the following formula E.

Formula E

In the formula E, X₁, X₂, Y₁ and Y₂ each represent a hydroxyl group, a halogen atom such as chlorine or bromine, an alkyl group such as methyl or ethyl, an aryl group such as phenyl or methoxyphenyl,
Here, R₂₁ and R₂₂ each represent a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, R₂₃ and R₂₄ each represent a substituted or unsubstituted alkylene group, and R₂₅ represents a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. M represents a cation as exemplified by sodium, potassium, lithium or ammonium. The alkyl group represented by R₂₁, R₂₂ and R₂₅ may preferably be an alkyl group having 1 to 6 carbon atoms. The alkylene group represented by the above R₂₃ and R₂₄ may preferably be an alkylene group having 1 to 2 carbon atoms.
Substituents on the alkyl group and aryl group represented by the above R₂₁, R₂₂ and R₂₅ and the alkylene group represented by the above R₂₃ and R₂₄ may preferably include a hydroxyl group, a sulfo group, a sulfoamino group and a carboxyamino group.
Examples of the group

may be an amino group, an alkylamino group as exemplified by methylamino, ethylamino, propylamino, dimethylamino, cyclohexylamino, β-hydroxyethylamino, di(β-hydroxyethyl)amino, β-sulfoethylamino, N-(β-sulfoethyl)-N-methylamino or N-(β-hydroxyethyl-N-methylamino, and an arylamino group as exemplified by anilino, o-, m- or p-sulfoanilino, o-, m-or p-chloroanilino, o-, m- or p-toluidino, o-, m- or p-carboxyanilino, o-, m- or p-hydroxyanilino, sufonaphthylamino, o-, m- or p-aminoanilino or o-, m- or p-anidino.
An example of the group

may be a morpholino group, and examples of the group -OR₂₅ may be an alkoxyl group as exemplified by methoxy, ethoxy or methoxyethoxy, an aryloxy group as exemplified by phenoxy or p-sulfophenoxy.
Of the fluorescent brightening agents represented by the above formulas, a preferred compound is a compound wherein all the X₁, X₂, Y₁ and Y₂ are each

A most preferred compound is a compound wherein one of X₂ and Y₁ is -OR₂₅ and the other is

and when one of X₂ and Y₂ is -OR₂₅ the other is
They specifically include the following compounds. Their examples are by no means limited to these.
The triazinylstilbene fluorescent brightening agent preferably used in the present invention can be synthesized by any conventional methods as disclosed, for example, in "Fluorescent Brightening Agents", Edited by KASEIHIN KOGYO KYOKAI, published August, 1976, page 8.
Of the exemplary compounds, particularly preferably used are E-4, E-24. E-34, E-35, E-36, E-37 and E-41.
The triazinylstilbene fluorescent brightening agent may preferably be used in an amount ranging from 0.2 g to 10 g, and more preferably from 0.4 g to 5 g, per liter of the color developing solution.
In the color developing solution used in the present invention, any of methyl cellosolve, methanol, acetone, dimethylformamide, β-cyclodextrin and besides the compounds disclosed in Japanese Patent Examined Publications No. 33378/1972 and No. 9509/1969 can be used as an organic solvent used to increase the solubility of developing agents.
Together with the organic solvent, it is also possible to use an auxiliary developing agents. Such an auxiliary developing agent is known to include, for example, N-methyl-p-aminophenol hexasulfate (Metol), phenidone, N,N-diethyl-p-aminophenol hydrochloride, and N,N,N′,N′-tetramethyl-p-phenylenediamine hydrochloride, which may preferably be added usually in an amount of 0.01 g/lit. to 1.0 g/lit.
It is still also possible to use other various additives such as an anti-stain agent, an anti-sludge agent and an interlayer effect accelerator.
From the viewpoint of effectively achieving the object of the present invention, it is preferred to add to the color developing solution of the present invention a chelating agent represented by the following formula K.

Formula K

In the formula K, E represents a substituted or unsubstituted alkylene, cycloalkylene, phenylene group, -R₁₅OR₁₅-, -R₁₅OR₁₅OR₁₅- or -R₁₅ZR₁₅. Z represents

R₁₁ to R₁₅ each represents a substituted or unsubstituted alkylene group. A₁ to A₅ each represent a hydrogen atom, -OH, -COOM or -PO₃(M)₂. M represents a hydrogen atom or an alkali metal atom.

(Exemplary Chelating Agents)

The color developing solution of the present invention may still also contain an anionic, cationic, amphoteric or nonionic surface active agent.
All the components for the above color developing solution may be used by successively adding them to a given amount of water. In this instance, the components with a low solubility to water can be added by mixing them with the organic solvent previously described such as triethanolamine.
As a more commonly available method, a plurality of components that can be present together stably one another may be previously made into an aqueous conc. solution or in the state of solids put in a small container, which may be added to water followed by stirring so that the resulting solution can be used as the color developing solution of the present invention.
In the present invention, the above color developing solution may be used at and desired pH range. From the viewpoint of rapid processing, it is preferably used at pH 9.5 to 13.0, and more preferably at pH 9.8 to 12.0. The processing temperature is not lower than 38°C, preferably 38.3°C to 43.0°C, and particularly preferably 39°C to 41°C. The processing time may preferably be within 90 seconds, more preferably 3 seconds to 60 seconds, and particularly preferably 5 seconds to 45 seconds.
In the present invention, since the effect of the present invention can be well obtained in the case of the low-replenishment, the color developing solution should be replenished preferably in an amount of not more than 120 ml/m², more preferably 20 ml/m² to 100 ml/m², and particularly preferably 25 ml/m² to 70 ml/m².
In the present invention, various processing methods can be used, including the monobath processing and other various methods as exemplified by the spray method in which the processing solution is sprayed, the web method in which a light-sensitive material is brought into contact with a carrier impregnated with the processing solution, and a developing method making use of a viscous processing solution.
In the present invention, the color development processing is followed by bleaching and fixing or monobath bleach-fixing. The monobath bleach-fixing is preferably used. A bleach-fixing solution used in the monobath bleach-fixing will be described below in detail.
In the bleach-fixing solution, an organic acid ferric complex salt such as aminopolycarboxylic acid is used. An organic acid that forms the organic acid ferric complex salt may preferably include an aminocarboxylic acid compound and an aminophosphonic acid compound, which respectively refers to an amino compound having at least one carboxylic acid group and an amino compound having at least one phosphonic acid group. They are more preferably be the compounds represented by the following formulas (1) and (2).

Formula (1)

Formula (2)

In the formula (1) and (2), E represents a substituted or unsubstituted alkylene group, a cycloalkylene group, a phenylene group, -R₅₅OR₅₅OR₅₅- or -R₅₅ZR₅₅. Z represents

R₅₁ to R₅₅ each represent a substituted or unsubstituted alkylene group. A₁ to A₅ each represent a hydrogen atom, -OH, -COOM or -PO₃M₂, wherein M represents a hydrogen atom or an alkali metal atom.
Preferred specific exemplary compounds of these compounds represented by the formulas (1) and (2) are shown below.

(Exemplary Compounds)

(1-1): Ethylenediaminetetraacetic acid
(1-2): Diethylenetriaminepentaacetic acid
(1-3): Ethylenediamine-N-(β-hydroxyethyl)-N,N′,N′-triacetic acid
(1-4): 1,3-Propylenediaminetetraacetic acid
(1-5): Triethylenetetraminehexaacetic acid
(1-6): Cyclohexanediaminetetraacetic acid
(1-7): 1,2-Diaminopropanetetraacetic acid
(1-8): 1,3-Diaminopropan-2-ol-2-tetraacetic acid
(1-9): Ethyl ether diaminetetraacetate
(1-10): Glycol ether diaminetetraacetate
(1-11): Ethylenediaminetetrapropionic acid
(1-12): Phenylenediaminetetraacetic acid
(1-13): Sodium ethylenediaminetetraacetate
(1-14): Tetra(trimethyl ammonium) ethylenediaminetetraacetate
(1-15): Tetrasodium ethylenediaminetetraacetate
(1-16): Pentasodium diethylenetriaminepentaacetate
(1-17): Sodium ethylenediamine-N-(β-hydroxyethyl)-N,N′,N′-triacetate
(1-18): Sodium propylenediaminetetraacetate
(1-19): Ethylenediaminetetramethylenephosphonic acid
(1-20): Sodium cyclohexanediaminetetraacetate
(1-21): Diethylenetriaminepentamethylenephosphonic acid
(1-22): Cyclohexanediaminetetramethylenephosphonic acid
(2-1): Nitrilotriacetic acid
(2-2): Iminodiacetic acid
(2-3): Hydroxyethyliminodiacetic acid
(2-4): Nitrilotripropionic acid
(2-5): Nitrilotrimethylenephosphonic acid
(2-6): Iminodimethylenephosphonic acid
(2-7): Hydroxyethyliminodimethylenephosphonic acid
(2-8): Sodium nitrilotriacetate

Of these aminocarboxylic acid compounds and aminophosphonic acid compounds, compounds particularly preferably used in view of the effect for the object of the present invention include the following:
(1-1), (1-2), (1-4), (1-5), (1-6), (1-7), (1-8), (1-10), (1-19), (2-1), (2-3) and (2-5).
Of these aminocarboxylic acid compounds and aminophosphonic acid compounds, particularly preferred compounds are compounds (1-1), (1-2), (1-4) and (1-8) because of their high bleaching performance and feasibility for rapid processing.
At least one of these ferric complex salts may be used. Two or more kinds of them may also be used in combination.
Any of these bleaching agents should preferably be used in an amount of 5 g/lit. to 450 g/lit., and more preferably 20 g/lit. to 250 g/lit. From the viewpoints of the rapid processing and the effect of preventing stain, it should be used particularly preferably in an amount of 80 g/lit. or more, and most preferably 100 g/lit. to 250 g/lit.
A solution so composed as to contain, in addition to the bleaching agent described above, a silver halide fixing agent and optionally a sulfite as a preservative is applied to the bleach-fixing solution. It is also possible to use a special bleach-fixing solution so composed as to be in combination of an iron (III) ethylenediaminetetraacetic acid complex bleaching agent and a large quantity of silver halide such as ammonium bromide.
As the above silver halide, besides the ammonium bromide, it is also possible to use hydrochloric acid, hydrobromic acid, lithium bromide, sodium bromide, potassium bromide, sodium iodide, potassium iodide, ammonium iodide, etc.
The above silver halide fixing agent contained in the bleach-fixing solution is a compound capable of forming a water-soluble complex salt as a result of reaction with a silver halide, as used in usual fixing, which is typically exemplified by thiosulfates such as potassium thiosulfate, sodium thiosulfate and ammonium thiosulfate, thiocyanates such as potassium thiocyanate, sodium thiocyanate and ammonium thiocyanate, thioureas, and thioethers. As a preferred example, it is effective to use ammonium salts as having a high diffusion rate to gelatin layers. Any of these fixing agents may be used in an amount not less than 5 g/lit. and within the range it can be dissolved. In usual instances, the fixing agent is used in an amount of 70 g/lit. to 250 g/lit, and preferably 100 g/lit. to 250 g/lit. in view of rapid processing.
In the bleach-fixing solution, it is also possible to incorporate, alone or in combination, various pH adjusters such as boric acid, borax, sodium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, acetic acid, sodium acetate and ammonium hydroxide.
It is still also possible to incorporate various kinds of fluorescent brightening agents, antifoaming agents or surface active agents. It is also possible to appropriately incorporate a preservative such as hydroxylamine, hydrazine or an addition product of a bisulfite addition compound of an aldehyde compound, an organic chelating agent such as aminocarboxylic acid, a stabilizer such as nitroalcohol or a sulfate, and an organic solvent such as methanol, dimethylsulfonamide or dimethylsulfoxide.
To the bleach-fixing solution, various bleach-accelerators can be added, including those disclosed in Japanese Patent O.P.I. Publication No. 280/1971, Japanese Patent Examined Publications No. 8506/1970 and No. 556/1971, Belgian Patent No. 770,910, Japanese Patent Examined Publications No. 8836/1970 and No. 9854/1978, Japanese Patent O.P.I. Publications No. 71634/1979 and No. 42394/1974, etc.
The bleach-fixing solution is commonly used at a pH of not less than 4.0 and not more than 9.5, and should preferably be used at a pH of not less than 4.5 and not more than 8.5. Stated more strictly, the bleach fixing is carried out most preferably at a pH of not less than 5.0 and not more than 8.0. The bleach-fixing solution is used at a processing temperature of not lower than 80°C, and preferably not lower than 35°C and not higher than 70°C, under control on evaporation or the like. A temperature higher than 70°C is not preferable in view of drying performance. A temperature lower than 35°C is not preferable in view of rapid processing. The processing time for bleach fixing may preferably be 2 seconds to 50 seconds, more preferably 3 seconds to 40 seconds, and most preferably 5 seconds to 30 seconds.
After the bleach fixing preferably employed in the present invention, it is preferred to carry out stabilizing by the use of a stabilizing solution.
The stabilizing solution may preferably contain a sulfite. The sulfite may be any of an organic salt or an inorganic salt so long as it can release sulfite ions. It is preferably an inorganic salt. As preferred specific compounds, it may include sodium sulfite, potassium sulfite, ammonium sulfite, ammonium bisulfite, potassium bisulfite, sodium bisulfite, sodium metabisulfite, potassium metabisulfite, ammonium metabisulfite and hydrosulfite. The above sulfite may preferably be added in such an amount that may be at least 1 x 10⁻³ mol/lit., and more preferably be added in such an amount that may range from 5 x 10⁻³ mol/lit. to 10⁻¹ mol/lit., in the stabilizing solution. Its addition in such an amount can be effective for the present invention, in particular, effective for preventing stain, and is preferably employed in the embodiments of the present invention. As methods for its addition, it may be directly added to the stabilizing solution, or may preferably be added to a stabilizing replenishing solution.
Particularly preferred compounds that can be added to the stabilizing solution may include ammonium compounds. These are fed by ammonium salts of various inorganic compounds, specifically including ammonium hydroxide, ammonium bromide, ammonium carbonate, ammonium chloride, ammonium hypophosphite, ammonium phosphate, ammonium phosphite, ammonium fluoride, ammonium acid fluoride, ammonium fluoroborate, ammonium arsenate, ammonium hydrogencarbonate, ammonium hydrogen fluoride, ammonium hydrogen sulfide, ammonium sulfate, ammonium iodide, ammonium nitrate, ammonium pentaborate, ammonium acetate, ammonium adipate, ammonium laurintricarboxylate, ammonium benzoate, ammonium carbamate, ammonium citrate,a ammonium diethyldithiocarbamate, ammonium formate, ammonium hydrogenmalate, ammonium hydrogenoxalate, ammonium hydrogenphthalate, ammonium hydrogentartarate, ammonium thiosulfate, ammonium sulfite, ammonium ethylenediaminetetraacetate, ferric ammonium ethylenediaminetetraacetate, ammonium lactate, ammoniummalate, ammonium maleate, ammonium oxalate, ammonium phthalate, ammonium picrate, ammonium pyrolidinedithiocarbamate, ammonium salicylate, ammonium succinate, ammonium sulfanylate, ammonium tartarate, ammonium thioglycolate, and ammonium 2,4,6-trinitrophenol. These may be used alone or in combination of two or more kinds.
The ammonium compound may be added in an amount preferably ranging from 0.001 mol to 1.0 mol, and more preferably ranging from 0.002 mol to 2.0 mols.
For achieving the object of the present invention, it is particularly preferred for the stabilizing solution to contain a chelating agent having a chelate stability constant with respect to iron ions, of not less than 8. Here, the chelate stability constant refers to the constant commonly known from L.G. Sillen and A.E. Martell, "Stability Constants of Metal-ion Complexes", The Chemical Society, London (1964), and S. Chaberek and A.E. Martell, "Organic Seqestering Agents", Wiley (1959).
The chelating agent having a chelate stability constant with respect to iron ions, of not less than 8 may include organic carboxylic acid chelating agents, organic phosphoric acid chelating agents, inorganic phosphoric acid chelating agents and polyhydroxyl compounds. The above iron ions are meant by ferric irons (Fe³⁺).
Specific chelating agents having a chelate stability constant with respect to iron ions, of not less than 8 can be exemplified by the following compounds, without limitation thereto. That is, they are ehtylenediaminediorthohydroxyphenylacetic acid, diaminopropanetetraacetic acid, nitrilotriacetic acid, N-hydroxyethylethylenediaminetetraacetic acid, dihydroxyethylglycine, ethylenediaminediacetic acid, ethylenediaminedipropionic acid, iminodiacetic acid, diethylenetriaminepentaacetic acid, hydroxyiminodiacetic acid, diaminopropanoltetraacetic acid, transcyclohexanediaminetetraacetic acid, glycol ether diaminetetraacetic acid, ethylenediaminetetrakismethylenephosphonic acid, nitrilotrimethylenephosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, 1,1-diphosphonoethane-2-carboxylic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 1-hydroxy-1-phosphonopropane-1,2,3-tricarboxylic acid, catechol-3,5-diphosphonic acid, sodium pyrophosphate, sodium tetrapolyphosphate, and sodium hexametaphosphate. Particularly preferred are diethylenetriaminepentaacetic acid, nitrilotriacetic acid, nitrilotrimethylenephosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, etc. In particular, 1-hydroxyethylidene-1,1-diphosphonic acid is most preferably used.
The above chelating agent may be used preferably in an amount of 0.01 g to 50 g, and more preferably 0.05 g to 20 g, per liter of the stabilizing solution, within the range of which good results can be obtained.
In addition to this agent, commonly known compounds that can be added in stabilizing solutions are polyvinylpyrrolidone such as PVP K-15, k-30 and K-90; organic acid salts such as citrates, acetates, succinates, oxalates and benzoates; pH adjusters such as phosphates, borates, hydrochlorides and sulfuric acid; mildewproofing agents such as phenol derivatives, catechol derivatives, imidazole derivatives, triazole derivatives, thiabenzole derivatives, organic halogen compounds, and other mildewproofing agents known as slime control agents used in paper-pulp industries; and also fluorescent brightening agents, surface active agents, antiseptic agents, and salts of metals such as Bi, Mg. Zn, Ni, Al, Sn, Ti and Zr. Any of these compounds may be used in any combination so long as they are necessary for maintaining the pH of the stabilizing bath and also do not adversely affect the stability required when color photographic images are stored, and the generation of precipitates.
In the stabilizing, the processing temperature may range from 15°C to 70°C, and preferably from 20°C to 55°C. The processing time may preferably be not more than 120 seconds, more preferably 3 seconds to 90 seconds, and most preferably 6 seconds to 50 seconds, within which the effect of the present invention can be better obtained.
After the stabilizing, it is not necessary at all to carry out washing. It, however, is possible to optionally carry out rinsing, surface washing or the like by washing with water in a small quantity and for a very short time. It is preferred for a soluble iron salt to be present in the stabilizing solution in order to obtain the effect of the present invention. The soluble iron salt may include inorganic iron salts such as ferric chloride, ferrous chloride, ferric phosphate, ferric bromide, ferric nitrate and ferrous nitrate, and organic acid iron salts such as ferric ethylenediaminetetraacetate, ferric 1-hydroxyethylidene-1,1-diphosphate, ferrous 1-hydroxyethylidene-1,1-diphosphate, ferrous ethylenediaminetetraacetate, ferric diethylenetriaminepentaacetate, ferrous diethylenetriaminepentaacetate, ferric citrate, ferrous citrate, ferric ethylenediaminetetramethylenephosphate, ferrous ethylenediaminetetramethylenephosphate, ferric nitrilotrimethylenephosphate and ferrous nitrilotrimethylenephosphate. These organic acid salts may be in the form of free acids, or of sodium salts, potassium salts, ammonium salts, lithium salts, or alkylammonium salts such as a triethanol ammonium salt, a trimethyl ammonium salt and a tetramethyl ammonium salt. These soluble salts may preferably be used in a concentration of at least 5 x 10⁻³ mol/lit., preferably in the range of 8 x 10⁻³ mol/lit. to 150 x 10⁻³ mol/lit., and more preferably in the range of 12 x 10⁻³ mol/lit. to 100 x 10⁻³ mol/lit., in the stabilizing solution. These soluble salts may be added to the stabilizing solution (tank solution) by adding any of them to a stabilizing solution replenisher. Alternatively, they may be added to the stabilizing solution (tank solution) by causing any of them to dissolve out from a light-sensitive material to the stabilizing solution. Still alternatively they may be added to the stabilizing solution (tank solution) by adhering any of them to a light-sensitive material being processed so that it can be carried in the stabilizing solution from a forebath.
In the present invention, a stabilizing solution having been made to have 5 pm or less of calcium ions and magnesium ions by an ion-exchange resin treatment may be used. A method wherein the mildewproofing previously described and a halogen ion releasing compound are incorporated in such a stabilizing solution may also be used.
The pH of the stabilizing solution may preferably be in the range of 5.5 to 10.0. The pH adjusters that can be contained in the stabilizing solution may be any of commonly known alkali agents and acid agents.
The stabilizing solution may be replenished in a quantity preferably 0.1 time to 50 times, and particularly preferably 0.5 time to 30 times, the carry-in quantity of a forebath (the bleach-fixing solution) per unit area of a light-sensitive material, in view of rapid processing performance and storage stability of dye images.
The stabilizing may preferably be carried out using 1 stabilizing tank to 5 stabilizing tanks, more preferably 1 tank to 3 tanks, and most preferably 1 tank in view of desilvering and rapid processing.
A light-sensitive material that is referable for applying the present invention will be described below.
Silver halide grains preferably used in the light-sensitive material are silver halide grains mainly composed of silver chloride, containing silver chloride in an amount of at least 80 mol %, preferably not less than 90 mol %, more preferably not less than 95 mol %, and most preferably not less than 99 mol %. This is effective for rapid processing and also for stain prevention. It is a preferred embodiment of the present invention to process a light-sensitive material making use of such a silver halide emulsion mainly composed of silver chloride.
The above silver halide emulsion mainly composed of silver chloride may contain, in addition to silver chloride, other silver halide comprised of silver bromide and/or silver iodide. In such an instance, silver bromide may preferably be in an amount of not more than 20 mol %, more preferably not more than 10 mol %, and still more preferably not more than 3 mol %. In the case when silver iodide is present, the silver iodide may preferably be in an amount of not more than 1 mol %, more preferably 0.5 mol %, and most preferably 0 mol %. Such silver halide grains mainly composed of silver chloride, containing 80 mol % or more of silver chloride, may be applied to at least one silver halide emulsion layer. They may more preferably be applied to all silver halide emulsion layers.
The crystals of the silver halide grains described above may be regular crystals or twinned crystals, or may be of any other form. Those having any ratio of [1.0.0] face to [1.1.1] face can be used. With regard to the crystal structure, these silver halide grains may have a structure which is uniform from the interior to the outer surface, or a layer structure wherein the inside and the outer surface are of different nature (i.e., a core/shell type). These silver halide grains may be of the type wherein a latent image is mainly formed on the surface, or the type wherein it is formed in the interior of grains. Tabular silver halide grains (see Japanese Patent O.P.I. Publication No. 113934/1983 and Japanese Patent O.P.I. Publication No. 47959/1986) can also be used. It is also possible to use the silver halide grains as disclosed in Japanese Patent O.P.I. Publications No. 26837/1989, No. 26838/1989 and No. 77047/1989.
The above silver halide grains may be those obtained by any preparation method such as the acid method, the neutral method or the ammonia method.
They may also be those prepared by a method in which seed grains are formed by the acid method, which are then made to grow by the ammonia method capable of achieving a higher grow rate until they come to have a given size. When the silver halide grains are grown, it is preferred to control the pH, pAg, etc. in a reaction vessel and to successively and simultaneously add and mix silver ions and halide ions in the amounts corresponding to the rate of growth of silver halide grains, as in the manner disclosed, for example, in Japanese Patent O.P.I. Publication No. 48521/1979.
The silver halide emulsion layer of the light-sensitive material processed by the method of the present invention has color couplers. These color couplers react with oxidized products of color developing agents to form non-diffusible dyes. The color couplers may advantageously be combined in a non-diffusible form in a light-sensitive layer or in contiguity thereto.
Thus, a red-sensitive layer can contain, for example, a non-diffusible color coupler capable of producing a cyan-part color image, usually a phenol or α-naphthol coupler. A green-sensitive layer can contain, for example, at least one non-diffusible color coupler capable of producing a magenta-part color image, usually a 5-pyrazolone or pyrazolotriazole coupler. A blue-sensitive layer can contain, for example, at least one non-diffusible color coupler capable of producing a yellow-part color image, usually a color coupler having an open chain ketomethylene group. The color couplers can be, for example, six-, four- or two-equivalent couplers.
In the present invention, two-equivalent couplers are particularly preferred.
Suitable couplers are disclosed, for example, in the following publications: Mitteilungen aus den Forschungslaboratorien der Agfa; W. Pelz, "Farbkuppler" in Leverkusen/München, Vol. III, p.111 (1961); The Chemistry of Synthetic Dyes, Vol. 4, pp.341-387, Academic Press; and The Theory of the Photographic Process, Fourth Edition, pp.353-362; and Research Disclosure No. 17643, Section VII.
In the present invention, it is particularly preferred in view of the effect for achieving the object of the present invention to use the magenta coupler represented by Formula M-1 as described on page 29 of Japanese Patent O.P.I. Publication No. 106655/1985 (including as specific exemplary magenta couplers, the compounds No. 1 to No. 77 described on pages 26 to 34 of Japanese Patent O.P.I. Publication No. 106655/1985), the cyan couplers represented by the formula C-I or C-II also described on pages 34 (including as specific exemplary cyan couplers, the compounds C′-1 to C′-82 and C˝-1 to C˝-36 described on pages 37 to 42 of the same publication), the high-speed yellow couplers also described on page 20 (including as specific exemplary yellow couplers, the compounds Y′-1 to Y′-39 described on pages 21 to 26 of the same publication).
When a nitrogen-containing heterocyclic mercapto compound is used in the light-sensitive material making use of the emulsion mainly composed of silver chloride, not only the effect for achieving the object of the present invention can be well obtained but also an additional effect can be obtained such that any influence on photographic performances caused when a bleach-fixing solution has been unintentionally included in the color developing solution can be made very small. Hence, in the present invention, its use can be said to be a more preferred embodiment.
Such a nitrogen-containing heterocyclic mercapto compound can be exemplified by the compounds I′-1 to I′-87 described on pages 42 to 45 of the above Japanese Patent O.P.I. Publication No. 106655/1988.
The silver halide emulsion mainly composed of silver chloride, containing 80 mol % or more of silver chloride, can be prepared by any conventional methods, for example, the single-jet or double-jet method wherein materials are constantly or acceleratingly fed. It may preferably be prepared by the double-jet method under control of the pAg, see Research Disclosure No. 17643, Sections I and II.
The emulsion mainly composed of silver chloride can be chemically sensitized. Sulfur-containing compounds such as allylisothicyanate, allylthiourea and thiosulfate are particularly preferred therefor. Reducing agents can also be used as chemical sensitizers, which are exemplified by the silver compounds as disclosed in Belgian Patents No. 493,464 and No. 568,687, the polyamines such as diethylenetriamine, or aminomethylsulfine derivatives, as disclosed in Belgian Patent No. 547,323. Noble metals such as gold, platinum, palladium, iridium, ruthenium and rhodium and their noble metal compounds are also suitable sensitizers. This chemical sensitization is described in a paper by R. Kosiovsky, Zeitschrift für Wissenschaftrich Photographie (Z. Wiss. Photo.), 46, pp.65-72 (1951), see also the above Research Disclosure No. 17643, Section III.
The emulsion mainly composed of silver chloride can be optically sensitized by known methods using, for example, commonly available polymethine dyes such as neutrocyanine, rhodacyanine and hemicyanine, styryl dyes, oxonols and their analogues, see F.M. Hamer, "The Cyanine Dyes and Related Compounds" (1964), Ullmanns Enzyklpadie der Technischen Chemie, Fourth Edition, Vol. 18, p.431 and the next page, and the above Research Disclosure No. 17643, Section IV.
In the emulsion mainly composed of silver chloride, antifoggants and stabilizers can be used, which are conventionally used. Azaindenes are particularly suitable stabilizers, and tetraazaindene and pentaazaindene are preferred. In particular, those substituted with a hydroxyl group or an amino group are preferred. The compounds of this type are disclosed, for example, in a Birr's paper, Zeitschrift für Wissenschaftrich Photographie (Z. Wiss. Photo.), 47, pp.2-58 (1952) and the above Research Disclosure No. 17643, Section IV.
The components of the light-sensitive material can be incorporated by conventionally known methods, see, for example, U.S. Patents No. 2,322,027, No. 2,533,514, No. 3,689,271, No. 3,764,336 and No. 3,765,897. The components of the light-sensitive material, as exemplified by couplers and UV absorbents, can also be incorporated in the form of latex, see German Patent Application Publication No. 2,541,274 and European Patent Application No. 14,921. The components can also be fixed in the light-sensitive material in the form of polymers, see, for example, German Patent Application Publication No. 2,044,992, and U.S. Patents No. 3,370,952 and No. 4,080,211.
As supports for the light-sensitive material, usual supports can be used, which are exemplified by a support made of a cellulose ester such as cellulose acetate, and a support made of polyester. In the present invention, it is most suitable to use reflection-type supports such as a support made of paper. These may be coated, for example, with a polyolefin, in particular, polyethylene or polypropylene. In this regard, see the above Research Disclosure No. 17643, Sections V and VI.
The light-sensitive material for which the color developing solution of the present invention is used may be a light-sensitive material processed by what is called the coupler-in-emulsion type developing method, containing couplers in the light-sensitive material. The present invention can be applied to any light-sensitive materials of such a type, such as color papers, color negative films, color positive films, slide color reversal films, motion picture color reversal films, TV color reversal films and reversal color papers. The present invention is most preferably applied to color papers mainly composed of silver chloride.

EXAMPLES

The present invention will be described below in greater detail by giving Examples. The present invention is by no means limited by these Examples.

Example 1

On a paper support one side of which was laminated with polyethylene and the other side of which, the side on which the following layers were to be formed, was laminated with polyethylene containing titanium oxide, each layer with the constitution shown below was provided by coating, to produce a multi-layer light-sensitive silver halide color photographic material.
Coating solutions were prepared in the following way:

First layer coating solution:

In 6.67 g of a high-boiling organic solvent (DNP), 26.7 g of a yellow coupler (Y-1), 10.0 g of a dye image stabilizer (ST-1), 6.67 g of a dye image stabilizer (ST-2) and 0.67 g of an additive (HQ-1) were added and dissolved. The resulting solution was emulsifyingly dispersed using a homogenizer, in 220 ml of an aqueous 10 % gelatin solution containing 7 ml of a 20 % surface active agent (SU-1). Thus a yellow coupler dispersion was prepared.
This dispersion was mixed with a blue-sensitive silver halide emulsion (containing 10 g of silver) prepared under the conditions described later to give a first layer coating solution.
Second layer to seventh layer coating solutions were also prepared in the same procedure as the first layer coating solution.

DOP: Dioctylphthalate
DNP: Dinonylphthalate
DIDP: Diisodecylphthalate
PVP: Polyvinyl pyrrolidone

The following H-1 was used as a hardening agent.
H-1

Preparation of blue-sensitive silver halide emulsion:

In 1,000 ml of an aqueous 2 % gelatin solution kept at a temperature of 40°C, the following solution A and solution B were simultaneously added in 30 minutes while controlling the pAg and pH to be 6.5 and 3.0, respectively, and the following solution C and solution D were further simultaneously added in 180 minutes while controlling the pAg and pH to be 7.3 and 5.5, respectively.
At this time, the pAg was controlled by the method disclosed in Japanese Patent O.P.I. Publication No. 45437/1984 and the pH was controlled using an aqueous solution of sulfuric acid or sodium hydroxide.

Solution A:

Sodium chloride: 3.42 g
Potassium bromide: 0.03 g
By adding water, made up to: 200 ml

Solution B:

Silver nitrate: 10 g
By adding water, made up to: 200 ml

Solution C:

Sodium chloride: 102.7 g
Potassium bromide: 1.0 g
By adding water, made up to: 600 ml

Solution D:

Silver nitrate: 300 g
By adding water, made up to: 600 ml

After completion of the addition, the emulsion was desalted using an aqueous 5 % solution of Demol-N, produced by Kao Atlas Co and an aqueous 20 % solution of magnesium sulfate, and then mixed with an aqueous gelatin solution to give a monodisperse cubic emulsion EMP-1 having an average grain size of 0.85 µm, a variation coefficient (σ/r) of 0.07 and a silver chloride content of 99.5 mol %.
The above emulsion EMP-1 was subjected to chemical sensitization at 50°C for 90 minutes using the following compounds to give a blue-sensitive silver halide emulsion (EmA).

Sodium thiosulfate: 0.8 mg/mol·AgX
Chloroauric acid: 0.5 mg/mol·AgX
Stabilizer SB-5: 6.0 x 10⁻⁴ mg/mol·AgX
Sentizing dye D-1: 4.3 x 10⁻⁴ mg/mol·AgX
Sentizing dye D-4: 0.7 x 10⁻⁴ mg/mol·AgX

Preparation of green-sensitive silver halide emulsion:

The same procedure for the preparation of EMP-1 was repeated except that the addition time of the solutions A and B and the addition time of the solutions C and D were changed, to give a monodisperse cubic emulsion EMP-2 having an average grain size of 0.43 µm, a variation coefficient (σ/r) of 0.08 and a silver chloride content of 99.5 mol %.
The emulsion EMP-2 was subjected to chemical sensitization at 55°C for 120 minutes using the following compounds to give a green-sensitive silver halide emulsion (EmB).

Sodium thiosulfate: 1.5 mg/mol·AgX
Chloroauric acid: 1.0 mg/mol·AgX
Stabilizer SB-5: 6 x 10⁻⁴ mg/mol·AgX
Sentizing dye D-2: 4 x 10⁻⁴ mg/mol·AgX

Preparation of red-sensitive silver halide emulsion:

The same procedure for the preparation of EMP-1 was repeated except that the addition time of the solutions A and B and the addition time of the solutions C and D were changed, to give a monodisperse cubic emulsion EMP-3 having an average grain size of 0.50 µm, a variation coefficient (σ/r) of 0.08 and a silver chloride content of 99.5 mol %.
The emulsion EMP-3 was subjected to chemical sensitization at 60°C for 90 minutes using the following compounds to give a red-sensitive silver halide emulsion (EmC).

Sodium thiosulfate: 1.8 mg/mol·AgX
Chloroauric acid: 2.0 mg/mol·AgX
Stabilizer SB-5: 6 x 10⁻⁴ mg/mol·AgX
Sentizing dye D-3: 1 x 10⁻⁴ mg/mol·AgX

The sample thus obtained was exposed to light by a conventional method, and then processed under the following conditions and using the following processing solutions.

Processing conditions:

The amount of replenishment is an amount per 1 m² of the light-sensitive material. In the stabilizing, the stabilizing tanks were arranged in a third to first countercurrent system to carry out replenishment.
The respective processing solutions were composed in the following way:

Color developing tank solution

Made up to 1 liter in total by adding water, and adjusted to pH 10.10 with potassium hydroxide or sulfuric acid.

Color developing replenishing solution

Made up to 1 liter in total by adding water, and adjusted to pH 12-00 with potassium hydroxide or sulfuric acid.

Bleach-fixing tank solution and replenishing solution

Adjusted to pH 5.4 with ammonia water or glacial acetic acid, and made up to 1 liter in total by adding water.

Stabilizing tank solution and replenishing solution

Adjusted to pH 7-8 with ammonia water or sulfuric acid, and made up to 1 liter by adding water.
Using the color paper and processing solutions thus prepared, running processing was carried out.
The running processing was carried out in the following way: Tanks of an automatic processor were filled with the above color developing tank solution and also with the above bleach-fixing tank solution and stabilizing tank solution. While the above color paper sample was processed, the above color developing replenishing solution, bleach-fixing replenishing solution and stabilizing replenishing solution were supplied at intervals of 3 minutes through metering pumps.
The running processing was intermittently carried out at 0.05 R per day until the amount of the color developing replenishing solution supplied in the color developing tank solution reached 3 times the capacity of the color developing tank. Here, 1R means that the color developing replenishing solution is supplied in the amount corresponding to the capacity of the color developing tank.
Color-forming performances, fog and gradation in the above running processing were measured on their values at the start of running processing and at the time of its completion, and values of variations on the values at the time of completion with respect to the values at the start were determined.
With regard to the color-forming performances, maximum yellow color-forming density (Y-Dmax) was measured, and with regard to the fog, yellow color-forming density of unexposed area (Y-Dmin). The gradation was expressed as tanϑ determined from the following equation. tanϑ = {(minimum reflection density + 0.5) - (minimum reflection density + 0.1)}/(logE₁ - logE₂)

logE₁:: Logarithmic value of the amount of exposure at (minimum reflection density + 0.5)
logE₂:: Logarithmic value of the amount of exposure at (minimum reflection density + 0.1)

The values of variations were determined in the following way:
Variation value of Y-Dmax, ΔY-Dmax = Y-Dmax₁ - Y-Dmax₂

Y-Dmax₁:: Y-Dmax at the time of the completion of running processing
Y-Dmax₂:: Y-Dmax at the time of the start of running processing

Y-Dmin₁:: Y-Dmin at the time of the completion of running processing
Y-Dmin₂:: Y-Dmin at the time of the start of running processing

tanϑ₁:: tanϑ at the time of the completion of running processing
tanϑ₂:: tanϑ at the time of the start of running processing

Results obtained are shown in Table 1.
The buffering agents used for comparison are as shown in the following. When two kinds of buffering agents were used in combination, they were added in equimolar amounts for each.
As is clear from Table 1, the combination according to the present invention has made it possible to provide a processing method that is superior in color-forming performance or fog, and causes less variations in color-forming performance, fog and gradation, that are due to the influences of the components dissolved out form the light-sensitive material which accumulate as a result of low-replenishing running processing.

Example 2

Running processing was carried out under the same conditions as in the processing No. 1-8 of Example 1 except that the chelating agent, diethylenetriaminepentaacetic acid used in the color developing tank solution and color developing replenishing solution was replaced with those as shown in Table 2 and the color developing replenishing solution was supplied in an amount of 30 ml/m². Color-forming performance, fog and gradation were similarly evaluated to obtain the results shown in Table 2.
As is clear from Table 2, the incorporation of the chelating agent as described in the present specification can make the present invention more effective.

Example 3

Experiments were carried out under the same conditions as in the processing No. 1-8 of Example 1 except that the brightening agents as shown in Table 3 were each added to the color developing tank solution and color developing replenishing solution and the color developing replenishing solution was supplied in an amount of 30 ml/m². Evaluation was similarly made to obtain the results shown in Table 3.
The brightening agents were each added in an amount of 2.0 g/lit in the color developing tank solution and 4.0 g/lit. in the color developing replenishing solution.
As is clear from Table 3, the addition of the triazinylstilbene type brightening agent can make the present invention more effective.

Example 4

Experiments were carried out under the same conditions as in the processing No. 1-8 of Example 1 except that the preservative, N,N-diethylhydroxylamine used in the color developing tank solution and color developing replenishing solution was replaced with the preservatives as shown in Table 4, which were added so as to be in equimolar amounts, and the color developing replenishing solution was supplied in an amount of 30 ml/m². Evaluation was similarly made to obtain the results shown in Table 4.
As will be clear from Table 5, the addition of the organic preservative represented by the formula A or B makes the present invention more effective.
Example 5
Experiments were carried out under the same conditions as in the processing No. 1-8 of Example 1 except that the triethanolamine used in the color developing tank solution and color developing replenishing solution was replaced with the additives as shown in Table 5, which were added so as to be in equimolar amounts, and the color developing replenishing solution was supplied in an amount of 30 ml/m². Evaluation was similarly made to obtain the results shown in Table 5.
As will be clear from Table 5, the incorporation of the alkanolamine type compound represented by the formula C or the glycol type compound represented by the formula D can make the present invention more effective.
As having been described above, the present invention can improve the stability of photographic performances when light-sensitive silver halide color photographic materials are processed by the low-replenishing method, in particular, when they are intermittently processed in a small processing quantity. Stated specifically, it can provide a method of processing a light-sensitive silver halide color photographic material, that can obtain a stable color-forming performance, i.e., maximum density, can give less fog density and also may cause less variations of gradation.

Claims

A method for processing a light-sensitive silver halide color photographic material, wherein the photographic material is processed in a color developing solution containing a chloride in a concentration of not less than 6 x 10⁻² mol/ℓ and a buffering agent having a pKa value of not less than 10.5, at a temperature of not lower than 38 °C.
A method of claim 1, wherein the chloride is contained within the range of 8.0 x 10⁻² to 2.0 x 10⁻¹ mol/ℓ.
A method of claim 1, wherein the buffering agent has a pKa value of 11.0 to 13.0.
A method of claim 1, wherein the photographic material is processed at a temperature of 38.3 to 43.0 °C.
A method of claim 1, wherein the buffering agent is phosphoric acid.
A method of claim 1, wherein the developing solution further contains a compound represented by formula A or B:
formula A
wherein R₁ and R₂ each represent a hydrogen atom, an alkyl or aryl group, or R′- CO-, provided that both are not hydrogen atoms at the same time; R′ represents an alkoxy, alkyl or aryl group,
formula B
wherein R₃, R₄ and R₅ each represent a hydrogen atom, an alkyl, aryl or heterocyclic group, R₆ represents a hydroxyl group, a hydroxylamino group, an alkyl, aryl, heterocyclic, alkoxy, aryloxy, carbamoyl or amino group; and R₇ represents a divalent group selected from -CO-, -SO₂- and -C(=NH)- and n is 0 or 1, provided that when n is 0, R₆ represents a group selected from an alkyl, aryl or heterocyclic group; R₅ and R₆ may combine to form a heterocyclic ring.
A method of claim 6, wherein the compound is contained in an amount of 0.2 to 50 g/ℓ.
A methd of claim 1, wherein the developing solution further contains a compound represented by formula C or D:
formula C
wherein R₈ represents hydroxyalkyl group, R₉ and R₁₀ each represent a hydrogen atom, an alkyl group, a hyroxyalkyl group, a benzyl group or a group represented by the formula:
wherein n′ represents an integer of 1 to 6, X and Y each represent a hydrogen atom, an alkyl group, or a hydroxyalkyl group,
formula D
wherein A and B each represent a branched or unbranched alkylene group, and n˝ and m each represent an integer of 0 to 100, provided that n˝ and m are not 0 at the same time.
A method of claim 8, wherein the compound of formula C or D is contained in an amount of 1 to 100 g/ℓ..
A method of claim 1, wherein the developing solution further contains a compound represented by formula E:
formula E
wherein X₁, X₂, Y₁ and Y₂ each represent a hydroxy group, a halogen atom, an alkyl group,an aryl group,
wherein R₂₁ and R₂₂ each represent a hydrogen atom, an alkyl or aryl group, R₂₃ and R₂₄ each represent an alkylene group, and R₂₅ represents a hydrogen atom, or an alkyl or aryl group, and M represents a cation.
A method of claim 10, wherein the compound of formula E is contained in an amount of 0.2 to 10.0 g/ℓ.
A method of claim 1, wherein the developing solution further contains a compound represented by formula K:
formula K
wherein E represents an alkylene, cycloalkylene or phenylene group, -R₁₅OR₁₅-, -R₁₅OR₁₅OR₁₅- or -R₁₅ZR₁₅-; Z represents
R₁₁ through R₁₅ each represent an alkylene group; A₁ through A₅ each represent a hydrogen atom, -OH, -COOM or -PO₃(M)₂; and M represents a hydrogen atom or an alkali metal atom.
A method of claim 1, wherein the photographic material is processed within a time of 90 seconds.
A method of claim 1, wherein the developing solution is replenished in an amount of 20 to 100 mℓ Per m² of the photographic material.
A method of claim 1, wherein the photographic material comprises a silver halide emulsion layer containing silver halide grains each having a silver chloride content of at least 80 mol%.
A method for processing a light-sensitive silver halide color photographic material, wherein the photographic material is processed in a color developing solution, at a temperature of not lower than 38 °C, containing a chloride in a concentration of 8.0 x 10⁻² to 2.0 x 10⁻² mol/ℓ; a buffering agent having a pKa value of 11.0 to 13.0; a compound represented by the following formula A or B; and a compound represented by the following formula E:
formula A
wherein R₁ and R₂ each represent a hydrogen atom, an alkyl or aryl group, or R′ CO , provided that both are not hydrogen atoms at the same time; R′ represents an alkoxy, alkyl or aryl group,
formula B
wherein R₃, R₄ and R₅ each represent a hydrogen atom, an alkyl, aryl or heterocyclic group, R₆ represents a hydroxyl group, a hydroxylamino group, an alkyl, aryl, heterocyclic, alkoxy, aryloxy, carbamoyl or amino group; and R₇ represents a divalent group selected from -CO-, -SO₂- and -C(=NH)- and n is 0 or 1, provided that when n is 0, R₆ represents a group selected from an alkyl, aryl or heterocyclic group; R₅ and R₆ may combine to form a heterocyclic ring.
formula E
wherein X₁, X₂, Y₁ and Y₂ each represent a hydroxy group, a halogen atom, an alkyl group,an aryl group,
wherein R₂₁, and R₂₂ each represent a hydrogen atom, an alkyl or aryl group, R₂₃ and R₂₄ each represent an alkylene group, and R₂₅ represents a hydrogen atom, or an alkyl or aryl group, and M represents a cation.