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Description  |
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FIELD OF THE INVENTION
The present invention relates to a process for processing a silver halide color photographic material and, more particularly, to a process for processing which reduces the amount of waste liquor and decreases running cost by reusing a used
bleach-fixing solution in continuous processing.
BACKGROUND OF THE INVENTION
In processing silver halide color photographic materials, used processing solutions are generally discharged as an overflow solution However, since such overflow solution still contains active ingredients, many studies have been conducted on
so-called regeneration techniques of utilizing the overflow solution as a replenisher by adding thereto deficient ingredients. Reuse of the overflow solution as a replenisher is preferable not only because running cost is decreased since amounts of
chemicals to be used can be decreased in comparison with the case of newly prepared replenishers but because environmental pollution is markedly reduced since the amount of overflow waste is decreased, thus being preferable in view of preservation of the
environment, too.
However, it is difficult to develop the technique of regenerating the overflow solution, and regeneration of a bleach-fixing solution has been believed to be particularly difficult. A bleach-fixing solution generally contains at least three
chemicals having different functions, i.e., an iron aminopolycarboxylate (III) complex as a bleaching agent, a thiosulfate as a fixing agent, and a sulfite as a preservative. An overflow solution of the bleach-fixing solution further contains silver
ions and color developer ingredients brought over from a prebath. In addition, it contains iron aminopolycarboxylate (II). In reusing this solution, there arises delayed desilvering, conversion of a cyan dye to its leuco form (color restoration
failure) or undesirable stain (stain or background) due to accumulation of halide ions or silver ions, accumulation of iron aminopolycarboxylate (II), and accumulation of developer ingredients or accumulation of a sulfate produced as a result of the
oxidation of the sulfite ion.
In order to solve the above-described problems, various regeneration techniques have been proposed. A technique of bringing a used solution into contact with metallic iron (steel wool) is disclosed, for example, in Radiography, 29, 256-259
(1963), and JP-A-48-2624 (the term "JP-A" as used herein refers to a "published unexamined Japanese patent application"). In accordance with this technique, the silver ion concentration can be decreased by recovering metallic silver formed by the
contact between silver ions and metallic iron, but the oxidizing power of the bleach-fixing solution is reduced since the metallic iron dissolves out as an iron (II) ion having a strong reducing ability, thus desilvering failure or color restoration
failure is likely to occur. The possibility of this problem arising increases as the silver ion concentration decreases.
A technique of recovering silver ions by reducing it through electrolysis is described, for example, in JP-A-50-98837, JP-A-51-19535, JP-A-51-36136, and U.S. Pat. No. 4,014,764. In this technique, too, an iron (III) complex is concurrently
reduced to an iron (II) complex, or a sulfite ion around a cathode is oxidized to a sulfate ion, thus desilvering failure or color restoration failure is also likely to occur and, at the same time, solution stability is decreased. The above described
problems become more serious as the amount of electric current is increased to decrease the iron ion concentration in the bleach-fixing solution by increasing the yield of silver recovery.
A technique of removing the silver complex by adsorbing it with an ion exchange resin is described, for example, in J. Appl. Photogr. Eng. 6, 14-18 (1980), SMPTE J, 93, 800-807 (1984). However, this technique requires the liberation of the
adsorbed iron complex from the resin for regeneration of the resin. Hence, procedures for effecting the technique are complicated, and a large amount of waste liquor is produced. Thus, this technique is not satisfactory in view of running cost.
JP-A-48-49437 and JP-A-50-145231 disclose a technique of regenerating the overflow solution by decreasing the equilibrium accumulation amount of silver ion through dilution or the like without positively removing silver. This technique is simple
and less costly because no special desilvering apparatuses are required. In this technique, however, the accumulation of silver halide dissolved from the light-sensitive material, particularly dissolved silver bromide is present in a large amount, and
the accumulation of sulfate delays desilvering. In addition, the accumulation of developer ingredients causes undesired stain and tends to cause color restoration failure. Thus, this technique involves problems as to the stability of running
properties.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a process for regenerating a used bleach-fixing solution which solves the problem of desilvering failure due to the accumulation of silver ions or sulfate radicals and, at the same time, prevents
stain or color restoration failure.
The inventors have found that the above described object can be attained by a process for processing a silver halide color photographic material, which comprises color developing and bleach-fixing the silver halide color photographic material,
and then processing by at least one of washing the material with water and stabilizing the material, the silver halide color photographic material comprising a support having thereon at least one emulsion layer comprising a silver chloride-rich emulsion
having a silver chloride content of 80 mol % or more and a used bleach-fixing solution which has been already used for said bleach-fixing solution, i.e., an overflow bleach-fixing solution, having a silver ion concentration of 0.02 mol/liter or more
being used as a bleach-fixing solution for replenishment.
The above described object can be more effectively attained by a process for processing a silver halide color photographic material, wherein the silver halide color photographic material contains at least one yellow coupler represented by formula
(I): ##STR3## wherein X represents a substituent, Y represents a releasing group represented by ##STR4## wherein Z represents a heterocyclic ring, and m represents an integer of 1 to 5.
DETAILED DESCRIPTION OF THE INVENTION
The silver ion concentration of the bleach-fixing solution for replenishment of the present invention being 0.02 mol/liter or more means that, even when the silver ion concentration dissolved into an overflow solution is increased as a result of
continuous processing, the silver ion is not removed from the overflow solution or desilvering is conducted to such a degree that the silver ion concentration does not become less than 0.02 mol/liter. When the silver ion is positively removed as is
conventionally done to decrease the silver ion concentration to as low as about 0.01 mol/liter or less, there arise the following problems. That is, in the electrolytic technique, desilvering failure or conversion of cyan dye to a leuco form thereof is
likely to occur due to the production of iron (II) complex or the accumulation of sulfate ions. In the case of using metallic iron, an iron (II) complex is formed in such a large amount that the oxidation power of the bleach-fixing solution is
decreased, thus desilvering failure is likely to occur. Therefore, in the present invention, a technique of regenerating a bleach-fixing solution without extremely decreasing silver ion concentration is used. A mere increase in the amount of
accumulated silver ion leads to a decrease in the desilvering rate as described in JP-A-50-145231. In the present invention, however, it has been found that the above described problem can be solved by using a silver chloride-rich emulsion (i.e., high
silver chloride emulsion) as the silver halide emulsion. That is, the present invention is based on the discovery that the accumulation of silver ions is largely influenced by a halide ion which is a counter ion of a silver ion and that the accumulation
of silver iodide or a large amount of silver bromide seriously decreases the initial desilvering rate whereas the accumulation of a large amount of silver chloride scarcely influences the desilvering properties of a silver chloride emulsion. With a
silver chloride-rich emulsion (i.e., a high silver chloride emulsion) containing a slight amount of silver bromide, slight dissolution of the silver bromide scarcely influences the desilvering properties of the emulsion.
As is described above, the present invention enables continuous processing without substantial removal of silver ion while not preventing desilvering properties contrary to the conventional knowledge that silver ions present in a dissolved state
must be removed as much as possible, which is quite unexpected.
In the present invention, the amount of accumulated silver ion is generally 0.02 mol/liter or more, preferably 0.02 to 0.4 mol/liter, more preferably 0.04 to 0.3 mol/liter. If the amount of accumulated silver ion is too much, desilvering failure
is easily generated, thus such excess amounts are not preferable.
In the case of conducting bleach-fixing processing immediately after color development, a light-sensitive material using a silver chloride-rich emulsion in each emulsion layer sometimes suffers processing unevenness due to incomplete stopping of
development with a bleach-fixing solution resulting from a too rapid color developing rate as is described in International Laid-Open No. WO 87/04534. Such unevenness is easily generated when processing is conducted in a roller transporting automatic
developing machine in which the transporting time between color development and bleach-fixing (light-sensitive material transporting time) is longer. It is worthy of special mention that the above described processing unevenness can be removed by
processing with a bleach-fixing solution having a comparatively high silver ion concentration as in the present invention.
In the process of the present invention for regenerating a used bleach-fixing solution (i.e., overflow solution), it is preferable not to remove silver ions from the overflow solution or to dilute it with water only to such a degree that the
silver ion concentration does not become less than 0.02 mol/liter and add only deficient ingredients, i.e., regenerating agents (for example, a bleaching agent, a fixing agent and a preservative) for reusing the overflow solution as a bleach-fixing
solution for replenishment. Various processes for recovering silver may be employed in combination with the process of the present invention. For example, silver ions may be properly removed under mild conditions according to the process of
electrically recovering silver (process of electrolytically recovering silver) described in JP-A-51-19535, JP-A-48-18191, JP-A-51-19535 and JP-A-51-36136 or the process of recovering silver by bringing the silver ions into contact with metallic iron as
described in JP-A-48-3624, and regenerating ingredients may be added thereto to prepare a bleach-fixing solution for replenishment (i.e., a replenishing bleach-fixing solution).
The kinds and amounts of the ingredients to be added to the used bleach-fixing solution may be easily decided by previously selecting kinds and amounts thereof capable of providing satisfactory photographic properties.
The bleach-fixing solution to be used in the present invention is described in detail below.
As the oxidizing agent to be used in the bleach-fixing solution of the present invention, an iron (III) aminopolycarboxylate complex is preferably used. The aminopolycarboxylic acid for the iron (III) aminopolycarboxylate complex includes
ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, 1,3-diaminopropanetetraacetic acid, propylenediaminetetraacetic acid, nitrilotriacetic acid, cyclohexanediaminetetraacetic acid, methyliminodiacetic acid, iminodiacetic acid, and glycol
ether diaminetetraacetic acid.
These compounds may be in the form of a sodium salt, a potassium salt, a lithium salt or an ammonium salt. Of these compounds, iron (III) complex salts of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid,
cyclohexanediaminetetraacetic acid, 1,3-diaminopropanetetraacetic acid and methyliminodiacetic acid are preferable because of their higher bleaching ability.
These ferric ion complex salts may be used in the form of complex salts or may be formed in situ in the solution using a ferric salt such as ferric sulfate, ferric chloride, ferric nitrate, ferric ammonium sulfate or ferric phosphate and a
chelating agent such as an aminopolycarboxylic acid. The chelating agent may be used in an excess amount of more than is necessary for forming the ferric ion complex salt. Of the iron complexes, iron aminopolycarboxylate complexes are preferable, and
are added in amounts of generally 0.01 to 1.0 mol/liter, preferably 0.05 to 0.50 mol/liter. In the bleach-fixing solution of the present invention, various compounds may be used as bleaching accelerators. For example, mercapto group- or disulfido
bond-containing compounds described in U.S. Pat. No. 3,893,858, West German Patent 1,290,812, JP-A-53-95630, and Research Disclosure, No. 17129 (July, 1978) and thiourea compounds described in JP-B-45-8506 (the term "JP-B" as used herein refers to an
"examined Japanese patent publication"), JP-A-52-20832, JP-A-53-32735 and U.S. Pat. No. 3,706,561 are preferable in view of the fact that they have an excellent bleaching ability.
Fixing agents to be used in the bleach-fixing solution in accordance with the present invention are known fixing agents, i.e., water-soluble silver halide-dissolving agents such as thiosulfates (e.g., sodium thiosulfate and ammonium thiosulfate),
thiocyanates (e.g., sodium thiocyanate and ammonium thiocyanate), thioether compounds (e.g., ethylenebisthioglycolic acid and 3,6-dithio-1,8-octanediol), and thioureas. These may be used alone or in a combination of two or more. In the present
invention, use of thiosulfates is preferable, with ammonium thiosulfate being particularly preferred. The amount of fixing agent per liter is preferably from 0.3 to 2 mols, more preferably from 0.5 to 1.0 mol.
The bleach-fixing solution or the fixing solution contains as a preservative a compound capable of releasing a sulfite ion such as a sulfite (e.g., sodium sulfite, potassium sulfite or ammonium sulfite), a bisulfite (e.g., ammonium bisulfite,
sodium bisulfite or potassium bisulfite), or a metabisulfite (e.g., potassium metabisulfite, sodium metabisulfite or ammonium metabisulfite). These compounds are incorporated in amounts of preferably about 0.02 to about 0.50 mol/liter (in terms of
sulfite ion), more preferably 0.04 to 0.40 mol/liter.
It is preferable to use as a preservative a carbonyl-bisulfite adduct for the purpose of reducing the substantial concentration of sulfite ion and preventing an increase of sulfate ion resulting from regeneration. Preferable carbonyl compounds
include acetaldehyde, acetone, nicotinic aldehyde and benzaldehyde. These compounds may be added to a bleach-fixing solution separately from the sulfite or may be added in the form of an adduct.
The bleach-fixing solution to be used in the present invention has a pH of generally 4 to 7, preferably 5 to 6.75, in a processing tank. If the pH is higher than the upper limit, there can result desilvering failure, stain or uneven processing,
whereas if lower than the lower limit, there can result color restoration failure or stain due to deterioration of the solution. Bleach-fixing time is preferably 10 to 60 seconds, more preferably 20 to 50 seconds, from the point of view of fully
obtaining the advantages of the present invention. If the bleach-fixing time is longer than the longer limit, there results insufficient advantages of the present invention with respect to desilvering property and color restoration, whereas a time
shorter than the shorter limit, there can result desilvering failure.
In preparing the replenishing bleach-fixing solution in accordance with the present invention, deficient chemicals can be added to the overflow solution as regenerating agents. Such deficient chemicals include the aforementioned bleaching agent,
fixing agent, preservative, etc.
These compounds are added preferably in the ammonium salt form for the purpose of preventing the reduction of desilvering property. Specific examples thereof include iron (III) ammonium ethylenediaminetetraacetate, ammonium sulfite, ammonium
bisulfite and ammonium thiosulfate. In addition, various organic or inorganic acids may be added for the purpose of decreasing the pH of the solution. Preferable acids include acetic acid, nitric acid, citric acid, and hydrochloric acid.
In the course of regeneration, aeration or the addition of an oxidant (e.g., H.sub.2 O.sub.2 or persulfate) may be conducted, if desired, for improving the oxidizing power of the bleach-fixing solution.
The color developer to be used in the present invention is now described in detail below.
The color developer to be used in the present invention contains a p-phenylenediamine color developing agent. Typical examples thereof are illustrated below which, however, are not limitative at all.
D- 1 N,N-Diethyl-p-phenylenediamine
D- 2 2-Amino-5-diethylaminotoluene
D- 3 2-Amino-5-(N-ethyl-N-laurylamino)toluene
D- 4 4-[N-Ethyl-N-(.beta.-hydroxyethyl)amino]aniline
D- 5 2-Methyl-4-[N-ethyl-N-(.beta.-hydroxyethyl)amino]aniline
D- 6 4-Amino-3-methyl-N-ethyl-N-[.beta.-(methanesulfonamido)ethyl]aniline
D- 7 N-(2-Amino-5-diethylaminophenylethyl)methanesulfonamide
D- 8 N,N-Dimethyl-p-phenylenediamine
D- 9 4-Amino-3-methyl-N-ethyl-N-methoxyethylaniline
D-10 4-Amino-3-methyl-N-ethyl-N-.beta.-ethoxyethylaniline
D-11 4-Amino-3-methyl-N-ethyl-N-.beta.-butoxyethyl-aniline
Among these, D-4, D-5 and D-6 are preferred.
These p-phenylenediamine derivatives may be in the form of salts such as sulfates, hydrochlorides, sulfites and p-toluenesulfonates. The aromatic primary amine developing agents are used in amounts of preferably from about 0.1 g to about 20 g,
more preferably from about 0.5 g to about 10 g, per liter of the developer.
The color developer to be used in the present invention preferably does not substantially contain sulfurous acids or a hydroxylamine salt conventionally used as a preservative. These compounds, when brought into a postbath of the bleach-fixing
solution, reduce an oxidant of iron (III) aminopolycarboxylate complex to decrease its oxidizing power. These compounds exhibit this effect more markedly in the case of using a regenerated bleach-fixing solution and, therefore, can adversely affect
desilvering property or color restoration. The term "not substantially contain" means that concentration of the compound is not more than 2.0.times.10.sup.-3 mol/liter.
In order to solve the above described problem, it is preferable to use a hydroxylamine derivative or a hydrazine derivative represented by formula (II) or (III) in place of the hydroxylamine salt. ##STR5## wherein R.sub.a and R.sub.b, which may
be the same or different, each represents a hydrogen atom or an alkyl group, with the proviso that R.sub.a and R.sub.b do not represent a hydrogen atom at the same time.
The alkyl group contains 1 to 6, preferably 1 to 3, carbon atoms, and preferable substituents therefor include a hydroxy group, an alkoxy group, a carbonic acid group, a sulfonic acid group and a phosphonic acid group. Preferable specific
examples thereof are illustrated below. ##STR6##
Among these, II-1, II-4 and II-5 are preferred. These compounds may be in salt form with various acids or with alkali metals or alkaline earth metals. They are added in amounts of 0.2 g to 50 g, preferably 1.0 g to 10 g, per liter of the color
developer. ##STR7## wherein R.sup.1, R.sup.2 and R.sup.3 each independently represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group, R.sup.4 represents a hydrogen atom, a hydroxy group, a hydrazino group, an alkyl group, an
aryl group, a heterocyclic group, an alkoxy group, an aryloxy group, a carbamoyl group or an amino group, X.sup.1 represents a divalent group, and n represents 0 or 1, with the proviso that, when n=0, R.sup.4 represents an alkyl group, an aryl group or a
heterocyclic group, and R.sup.3 and R.sup.4 may be taken together to form a hetero ring.
The compounds represented by formula (III) to be used in the present invention, i.e., hydrazine analogs composed of hydrazines and hydrazides will be described in detail below.
R.sup.1, R.sup.2 and R.sup.3 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group (containing preferably 1 to 20 carbon atoms, e.g., methyl, ethyl, sulfopropyl, carboxybutyl, hydroxyethyl, cyclohexyl, benzyl
or phenethyl), a substituted or unsubstituted aryl group (containing preferably 6 to 20 carbon atoms, e.g., phenyl, 2,5-dimethoxyphenyl, 4-hydroxyphenyl or 2-carboxyphenyl) or a substituted or unsubstituted heterocyclic group (containing preferably 1 to
20 carbon atoms, being preferably a 5- or 6-membered ring, and containing at least one of oxygen, nitrogen, sulfur, etc., as a hetero atom; e.g., pyridin-4-yl or N-acetylpiperidin-4-yl).
R.sup.4 represents a hydrogen atom, a hydroxy group, a substituted or unsubstituted hydrazino group (e.g., hydrazino, methylhydrazino or phenylhydrazino), a substituted or unsubstituted alkyl group (containing preferably 1 to 20 carbon atoms,
e.g., methyl, ethyl, sulfopropyl, carboxybutyl, hydroxyethyl, cyclohexyl, benzyl, t-butyl or n-octyl), a substituted or unsubstituted aryl group (containing preferably 6 to 20 carbon atoms, e.g., phenyl, 2,5-dimethoxyphenyl, 4-hydroxyphenyl,
2-carboxyphenyl or 4-sulfophenyl), a substituted or unsubstituted heterocyclic group (containing preferably 1 to 20 carbon atoms, being preferably 5- or 6-membered ring, and containing at least one of oxygen, nitrogen, sulfur, etc., as a hetero atom;
e.g., pyridin-4-yl or imidazolyl), a substituted or unsubstituted alkoxy group (containing preferably 1 to 20 carbon atoms, e.g., methoxy, ethoxy, methoxyethoxy, benzyloxy, cyclohexyloxy or octyloxy), a substituted or unsubstituted aryloxy group
(containing preferably 6 to 20 carbon atoms, e.g., phenoxy, p-methoxyphenoxy, p-carboxyphenoxy or p-sulfophenoxy), a substituted or unsubstituted carbamoyl group (containing preferably 1 to 20 carbon atoms, e.g., unsubstituted carbamoyl,
N,N-diethylcarbamoyl or phenylcarbamoyl), or a substituted or unsubstituted amino group (containing preferably 0 to 20 carbon atoms, e.g., amino, hydroxyamino, methylamino, hexylamino, methoxyethylamino, carboxyethylamino, sulfoethylamino, N-phenylamino
or p-sulfophenylamino).
Further substituents for R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are preferably a halogen atom (e.g., chlorine or bromine), a hydroxy group, a carboxy group, a sulfo group, an amino group, an alkoxy group, an amide group, a sulfonamide group, a
carbamoyl group, a sulfamoyl group, an alkyl group, an aryl group, an aryloxy group, an alkylthio group, an arylthio group, a nitro group, a cyano group, a sulfonyl group, a sulfinyl group, etc., which may further be substituted.
X.sup.1 is preferably a divalent organic residue and specifically represents, for example, ##STR8##
n represents 0 or 1, provided that, when n is 0, R.sup.4 represents a group selected from substituted or unsubstituted alkyl, aryl and heterocyclic groups. R.sup.1 and R.sup.2, or R.sup.3 and R.sup.4, may be taken together to form a heterocyclic
group.
When n is 0, at least one of R.sup.1 to R.sup.4 preferably represents a substituted or unsubstituted alkyl group. In particular, those wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each represents a hydrogen atom or a substituted or
unsubstituted alkyl group are preferable (provided that R.sup.1, R.sup.2, R.sup.3 and R.sup.4 do not represent a hydrogen at the same time). Above all, those wherein R.sup.1, R.sup.2 and R.sup.3 represent a hydrogen atom, and R.sup.4 represents a
substituted or unsubstituted alkyl group, those wherein R.sup.1 and R.sup.3 each represents a hydrogen atom, and R.sup.2 and R.sup.4 each represents a substituted or unsubstituted alkyl group, and those wherein R.sup.1 and R.sup.2 each represents a
hydrogen atom, and R.sup.3 and R.sup.4 each represents a substituted or unsubstituted alkyl group (R.sup.3 and R.sup.4 optionally taken together to form a heterocyclic ring) are particularly preferable.
When n is 1, X.sup.1 preferably represents --CO--, and R.sup.4 preferably represents a substituted or unsubstituted amino group, and R.sup.1 to R.sup.3 each preferably represents a substituted or unsubstituted alkyl group.
The alkyl group represented by R.sup.1 to R.sup.4 contains preferably 1 to 10 carbon atoms, more preferably 1 to 7 carbon atoms. Preferred substituents for the alkyl group include a hydroxyl group, a carboxylic acid group, a sulfo group and a
phosphonic acid group. Where two or more substituents exist, they may be the same or different from each other.
The compounds of the general formula (III) may form bis derivatives, tris derivatives or polymers bound through R.sup.1, R.sup.2, R.sup.3 or R.sup.4.
Specific examples of the compounds represented by the general formula (III) are illustrated below which, however, do not limit the present invention in any way. ##STR9##
Specific examples other than those described above are described in European Patent Application 254280A, pages 11 to 24, Japanese Patent Application No. 61-171682, pages 12 to 22, Japanese Patent Application No. 61-173468, pages 9 to 19, and the
like.
Many of the compounds represented by formula (III) are commercially available, and may be synthesized according to general processes described in Organic Synthesis, Coll. Vol. 2, pages 208 to 213; Jour. Amer. Chem. Soc., 36, 1747 (1914);
Yukagaku (Oil Chemistry), 24, 31 (1975); Jour. Org. Chem., 25, 44 (1960); Yakuhin Zasshi (Journal of Chemicals), 91, 1127 (1971); Organic Synthesis, Coll. Vol. 1, page 450; Shin Jikken Kagaku Koza (New Lecture on Experimental Chemistry, Vol. 14, III,
pages 1621 to 1628 (Maruzen); Beil., 2, 559; Beil., 3, 117; E. B. Mohr et al., Inorg. Syn., 4, 32 (1953); F. J. Wilson and E. C. Pickering, J. Chem. Soc., 123, 394 (1923); N. J. Leonard & T. H. Boyer, J. Org. Chem., 15, 42 (1950); Organic Synthesis,
Coll. Vol. 5, page 1055; P. A. S. Smith, Derivatives of Hydrazine and Other Hydronitrogens Having N-N Bonds, pages 120 to 124 and 130 to 131 (THE BENJAMIN/CUMMINGS PUBLISHING COMPANY, 1983); Stanley R. Sandier Waif Karo, Organic Functional Group
Preparations, Vol. 1, Second Edition, page 457, etc.
The hydrazines or hydrazides represented by formula (III) are incorporated in the color developer in amounts of preferably 0.01 to 50 g, more preferably 0.1 to 30 g, most preferably 0.5 to 10 g, per liter of the color developer to use.
In addition, various preservatives may be used in the present invention. Preferable preservatives include triethanolamine, diethanolamine, catechol-3,5-disulfonate and catechol-3,4,5-trisulfonate.
The color developer to be used in the present invention has a pH of preferably 9 to 12, more preferably 9 to 11.0, and may further contain known developer ingredients.
In order to keep the pH at level described above, various buffer agents are preferably used. As such buffer agents, carbonates, phosphates, borates, tetraborates, hydroxybenzoates, glycine salts, N,N-dimethylglycine salts, leucine salts,
norleucine salts, guanine salts, 3,4-dihydroxyphenylalanine salts, alanine salts, aminobutyrates, 2-amino-2-methyl-1,3-propanediol salts, valine salts, proline salts, trishydroxyaminomethane salts, lysine salts, etc., may be used. Of these, carbonates,
phosphates, tetraborates and hydroxybenzoates are preferably used since they have the advantages that they have good dissolving properties and an excellent buffering ability in a high pH region of 9.0 or above, that they do not adversely affect
photographic properties (such as fogging) when added to a color developer, and that they are less expensive.
Specific examples of the buffer agents include sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, trisodium phosphate, tripotassium phosphate, disodium phosphate, dipotassium phosphate, sodium borate, potassium
borate, sodium tetraborate (borax), potassium tetraborate, sodium o-hydroxybenzoate (sodium salicylate), potassium o-hydroxybenzoate, sodium 5-sulfo-2-hydroxybenzoate (sodium 5-sulfosalicylate), and potassium 5-sulfo-2-hydroxybenzoate (potassium
5-sulfosalic-ylate), which, however, do not limit the present invention in any way.
The buffer agent is added to the color developer in an amount of preferably 0.1 mol per liter or more, particularly preferably 0.1 mol to to 0.4 mol per liter.
In addition, various chelating agents may be used in the color developer as agents for preventing precipitation of calcium or magnesium or for improving stability of the color developer.
Nonlimitative examples of the chelating agents are illustrated below: nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, triethylenetetraminehexaacetate, N,N,N-trimethylenephosphonic acid,
ethylenediamine-N,N,N',N'-tetramethylenephosphonic acid, 1,3-diamino-2-propanoltetraacetic acid, trans-cyclohexanediaminetetraacetic acid, nitrilotripropionic acid, 1,2-diaminopropanetetraacetic acid, hydroxyethyliminodiacetic acid, glycol ether
diaminetetraacetic acid, hydroxyethylenediaminetriacetic acid, ethylenediamine-o-hyiroxyphen-ylacetic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic
acid, catechol-3,4,6-trisulfonic acid, catechol-3,5-disulfonic acid, 5-sulfosalicylic acid and 4-sulfosalicylic acid.
These chelating agents may be used as a combination of two or more, if desired.
The chelating agent may be added in an amount sufficient to mask metal ions in the color developer. For example, it is generally added in an amount of about 0.1 g to about 10 g per liter.
An optional developing accelerator may be added to the color developer, if desired.
As a developing accelerator, there may be added, if desired, thioether compounds described, for example, in JP-B-37-16088, JP-B-37-5987, JP-B-38-7826, JP-B-44-12380, JP-B-45-9019 and U.S. Pat. No. 3,813,247, p-phenylenediamine compounds
described in JP-A-52-49829 and JP-A-50-155554, quaternary ammonium salts described, for example, in JP-A-50-137726, JP-B-44-30074, JP-A-56-156826 and JP-A-52-43429, p-aminophenols described in U.S. Pat. Nos. 2,610,122 and 4,119,462, amino compounds
described, for example, in U.S. Pat. Nos. 2,494,903, 3,128,182, 4,230,796, 3,253,919, JP-B-41-11431, U.S. Pat. Nos. 2,482,546, 2,596,926 and 3,582,346, polyalkylene oxides described, for example, in JP-B-37-16088, JP-B-42-25201, U.S. Pat. No.
3,128,183, JP-B-41-11431, JP-B-42-23883 and U.S. Pat. No. 3,532,501, 1-phenyl-3-pyrazolidones, hydrazines, isoionic compounds, ionic compounds, imidazoles, and the like.
The color developer preferably does not contain substantially benzyl alcohol. The term "not contain substantially" means to contain in an amount of up to 2.0 ml per liter of the developer, more preferably in no amount. Not containing
substantially benzyl alcohol causes less accumulation thereof in a bleach-fixing solution during continuous processing and prevents color restoration failure, generation of stain or processing unevenness, thus better results being obtained.
In the present invention, an optional antifogging agent may be added, if desired, in addition to a halide ion such as a chloride ion or a bromide ion. As the antifogging agent, alkali metal halides such as potassium iodide and organic
antifogging agents may be used. Typical examples of the organic antifogging agents include nitrogen-containing heterocyclic compounds such as benzotriazole, 6-nitrobenzimidazole, 5-nitroisoindazole, 5-methylbenzotriazole, 5-nitrobenzotriazole,
5-chlorobenzotriazole, 2-thiazolylbenzimidazole, 2-thiazolylmethylbenzimidazole, indazole, hydroxyazaindolizine, adenine, etc.
The color developer to be used in the present invention preferably contains a fluorescent brightening agent. As the fluorescent brightening agent, 4,4'-diamino-2,2'-disulfostilbene compounds are preferable. The fluorescent brightening agent is
added in an amount of from 0 to 10 g/liter, preferably from 0.1 to 6 g/liter.
If desired, various surface active agents such as alkylsulfonic acids, arylphosphonic acids, aliphatic carboxylic acids, aromatic carboxylic acids, etc., may further be added.
As to the time for processing in the color developer in accordance with the present invention, a processing time of 10 seconds to 120 seconds, preferably 20 seconds to 60 seconds, provides marked advantages of the present invention. The
processing temperature is generally 33.degree. to 45.degree. C., preferably 35.degree. to 40.degree. C.
As to the amount of the replenishing color developer (i.e., the color developer for replenishment) in continuous processing, an amount of 20 to 220 ml per m.sup.2, particularly 40 to 140 ml per m.sup.2, of the light-sensitive material is
preferable since the advantages of the present invention can be effectively obtained.
Furthermore, buffer agents, fluorescent brightening agents, chelating agents, antifungal agents, etc., may be added, if desired.
The time for processing with the bleach-fixing solution to be used in the present invention is from 10 seconds to 120 seconds, preferably from 20 seconds to 60 seconds. The processing temperature is generally 25.degree. to 45.degree. C.,
preferably 30.degree. to 40.degree. C. The amount of replenishing solution is 30 ml to 250 ml, preferably 40 ml to 150 ml per m.sup.2, of the light-sensitive material. A decrease in the amount of replenishing solution generally leads to an increase in
stain and the possibility of desilvering failure. In accordance with the present invention, however, the amount of replenishing bleach-fixing solution (i.e., bleach-fixing solution for replenishment) can be decreased without causing the above described
problems.
The silver halide color photographic material of the present invention is generally subjected to a water washing step and/or a stabilizing step after the bleach-fixing processing.
The amount of water to be used in the water washing step may be selected from a wide range depending upon characteristic properties of light-sensitive material (e.g., resulting from the kinds of materials such as couplers), end use, temperature
of the washing water, number of washing tanks (step number), replenishing manner (e.g., countercurrent system or cocurrent system) and other various factors. Of these, the relationship between the number of water washing tanks and the amount of water in
a multistage countercurrent system can be determined according to the method described in Journal of the Society of Motion Picture and Television Engineers, Vol. 64, pages 248 to 253 (May, 1955).
The multistage countercurrent system described in the above mentioned literature enables the amount of water to be markedly decreased. However, an increased residence time of water in the tank causes another problem in that suspended matter is
produced as a result of the propagation of bacteria. In processing the color light-sensitive material according to the present invention, it is extremely effective to reduce the contents of calcium and magnesium as described in JP-A-62-288838 for
solving the above described problem. In addition, isothiazolone compounds and thiabendazoles described in JP-A-57-8542, chlorine-containing bactericides such as sodium chlorinated isocyanurate, and bactericides such as benzotriazoles described in
Hiroshi Horiguchi, Bokin Bobaizai no Kagaku (Chemistry of Antibacterial and Antifungal Agents), Eisei Gijutsu-kai, Biseibutsu no Mekkin, Sakkin, Bobaigijutsu (Sterilizing and Antifungal Techniques against Microorganisms), and Nihon Bokin Bobai Gakkai
(The Japanese Antibacterial and Antifungal Society), Bokin Bobaizai Jiten (Antibacterial and Antifungal Book) may also be used.
The pH of the washing water to be used in processing the light-sensitive material of the present invention ranges generally from 4 to 9, preferably from 5 to 8. The temperature and time of washing may also be varied depending upon the
characteristic properties of the light-sensitive material, end use, etc., but, as a general guide, a washing temperature of 15.degree. to 45.degree. C. and a washing time of 20 seconds to 2 minutes, preferably a washing temperature of 25.degree. to
40.degree. C. and a washing time of 30 seconds to 1 minute and 30 seconds, are selected.
In accordance with the present invention, good photographic properties can be obtained without increased stain even by the above described short time washing with water.
Further, the light-sensitive material of the present invention may be processed directly with a stabilizing solution in place of the above mentioned washing water. In such stabilizing processing, all of the known techniques described in
JP-A-57-8543, JP-A-58-14834, JP-A-59-184343, JP-A-60-220345, JP-A-60-238832, JP-A-60-239784, JP-A-60-239749, JP-A-61-4054, JP-A-61-118749, etc., may be employed. In particular, a stabilizing bath containing 1-hydroxyethylidene-1,1-diphosphonic acid,
5-chloro-2-methyl-4-isothiazolin-3-one, a bismuth compound, an ammonium compound or the like is preferably used.
In addition, the aforesaid water washing is in some cases followed by stabilizing. An example thereof is a stabilizing bath containing formalin and a surface active agent, which is used as a final bath for processing color light-sensitive
materials for photographing use.
The silver halide color photographic material to be used in the present invention is now described in detail below.
The silver halide emulsion to be used in the present invention substantially comprises silver chloride. The term "substantially comprises silver chloride" means that the content of silver chloride based on the amount of total silver halide is 80
mol% or more, preferably 95 mol% or more, more preferably 98 mol% or more. From the point of desilvering properties, the higher the content of silver chloride, the more preferable. The silver chloride-rich emulsion (i.e., the high silver chloride
emulsion) of the present invention may contain a small amount of silver bromide or silver iodide. In some cases, the presence of silver halide other than silver chloride serves to provide advantages as to photosensitivity such as an increased amount of
light absorption, a strengthened adsorption of a spectral sensitizing dye and a decreased desensitization caused by a spectral sensitizing dye.
Silver halide grains contained in a photographic emulsion layer of the photographic light-sensitive material to be used in the present invention may have a layered crystal structure wherein the inner portion and the outer portion are different
from each other in phase composition, a multiphase conjunction structure, or a uniform structure, or, further, may comprise a mixture of them.
Silver halide grains in the photographic emulsion may be in a regular crystal form such as cubic, octahedral or tetradecahedral form, in an irregular crystal form such as a spherical or tabular form, in a form with crystal defects such as twin
plane, or in a composite form thereof.
As to grain size of the silver halide grains, both fine grains of not larger than about 0.2 .mu.m and large sized grains of up to about 10 .mu.m in projected area diameter may be used. The emulsion may be a polydisperse emulsion or a
monodisperse emulsion.
The silver halide photographic emulsion to be used in the present invention may be prepared according to processes described, for example, in Research Disclosure (RD), No. 17643 (December, 1978), pages 22 and 23, "I. Emulsion preparation and
types".
Monodisperse emulsions described, for example, in U.S. Pat. Nos. 3,574,628, 3,655,394 and British Patent 1,413,748 are also preferable.
Tabular grains of about 5 or more in aspect ratio are also usable in the present invention. Such tabular grains may be easily prepared according to processes described, for example, in Gutoff, Photographic Science and Engineering, Vol. 14, pages
248 to 257 (1970), U.S. Pat. Nos 4,434,226, 4,414,310, 4,433,048, 4,439,520 and British Patent 2,112,157.
The crystal structure may be a uniform structure, a structure wherein the inner portion and the outer portion are different from each other in halide composition, or a layered structure. Or silver halide crystals different from each other may be
conjuncted to each other by epitaxial conjunction or, further, crystals conjuncted to other compounds than silver halide such as silver rhodanide or lead oxide may be used.
In addition, a mixture of grains of various crystal forms may also be used.
The silver halide emulsions to be used in the present invention are usually subjected to physical ripening, chemical ripening and spectral sensitization before use. Additives to be used in these steps are described in Research Disclosure, Nos.
17643 and 18716. Places where such additives are described are tabulated in the table to be shown hereinafter.
The silver halide of the present invention is coated in a silver amount of generally 1 g to 0.4 g, preferably 0.8 g to 0.4 g, per m.sup.2. A smaller amount is better from the viewpoint of improving desilvering properties and removing processing
unevenness.
Known photographic additives to be used in the present invention are also described in the above described two Research Disclosures, and the related descriptions are shown in the following table.
__________________________________________________________________________ Additives RD 17643 RD 18716 __________________________________________________________________________ 1. Chemical Sensitizers Page 23 Page 648, right column 2.
Sensitivity Increasing -- Page 648, right column Agents 3. Spectral Sensitizers, Pages 23-24 Page 648, right column Supersensitizers to page 649, right column 4. Brightening Agents Page 24 -- 5. Antifoggants and Pages 24-25 Page 649, right
column Stabilizers 6. Light Absorbers, Filter Pages 25-26 Page 649, right column Dyes, and Ultraviolet to page 650, left Absorbers column 7. Antistaining Agents Page 25, Page 650, left to right co | | |
