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BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a processing method for a silver halide
color photographic material, in particular to a processing method which
makes it possible to substantially reduce the amount of waste liquor and,
in turn, the pollution of the environment. In addition, the invention also
pertains to a processing method which permits a saving in running cost.
(2) Prior Art
Various kinds of processing solutions have been formulated for processing
silver halide color photographic materials, and the processing solution
has continuously or periodically been supplemented with replenishing
solution during processing, while the overflow thereof has been recovered
or discarded. However, in recent years the environment has been disrupted
by an increase in effluent industrial waste liquors and the like and
therefore, it is desirable to minimize the amount of waste liquor from the
viewpoint of environmental protection. For this reason, various processing
methods have been investigated. The most general of such methods comprises
reducing the amount of processing solution to be supplemented, which is
also economically advantageous. Studies have been made regarding the
application of this method to a variety of processing solutions such as
color developers, bleaching solutions, fixing solutions and
bleaching-fixing solutions and it has already been put into practical use.
Moreover, other processing methods have also been proposed and disclosed
in, for instance, Japanese Patent Un-examined Publication Nos. 57-8543;
57-132146; 58-18631 and 59-184343 wherein even the amount of washing water
is substantially saved.
The color developer, among others, has an extremely high biological oxygen
demand (BOD.sub.5) and chemical oxygen demand (COD), which are considered
to be a measure of the degree of environmental pollution, and further has
a buffering effect at a high pH region. Therefore, such color developer
used cannot be discarded without treatment and there is no merit in
recovering the used color developer, since it does not contain any
valuable material such as silver. On the contrary, various studies have
been conducted regarding recycling the used color developer, since the
color developer per se is quite expensive and there have been proposed,
for instance, a method utilizing the electrodialysis technique as is
disclosed in Japanese Patent Un-examined Publication Nos. 53-7234;
53-37015; 53-149331; 54-19741 and 54-37731; a method using an ion exchange
resin as is disclosed in Japanese Patent Un-examined Publication Nos.
52-146236; 53-50737 and 53-96831; West German Patent No. 2,717,674 and the
like. According to these methods, it becomes possible to reduce the amount
of color developers discharged to some degree. However, these methods
require the use of an expensive apparatus and considerable expertise for
the maintenance thereof. Such being the case, these methods have been
adopted only in a few major laboratories, while in most laboratories the
recycling of the color developer has not yet been carried out.
SUMMARY OF THE INVENTION
It is, therefore, a primary object of the present invention to provide a
processing method for a silver halide color photographic material which
permits a substantial reduction in the amount of waste liquor and, in
turn, the degree of environmental pollution and in particular a
substantial reduction in the amount of color developer discharged.
The aforementioned purpose can be accomplished by using all or a part of
the overflow of a color developer as part of a processing solution used in
a process other than the color development process in a method for
continuously developing a silver halide color photographic material.
This and other objects of the present invention will be clear from the
following description.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In general, a replenishing solution for different kinds of processing
solution which is used in processes carried out after the developing
process is prepared by dissolving or diluting a concentrated processing
agent in or with water (sometimes hot water). While, according to the
process of this invention, the overflow of the color developer is used
instead of a diluent such as water for different processing solutions
other than color developer so as to reduce the amount of color developer
discharged. In this respect, the inventors of this invention have found
that a replenishing solution for a bleaching solution, a bleaching-fixing
solution or a fixing solution, among others, can be maintained at a
satisfactory level of performance of the replenishing solution by simply
adjusting the pH of the replenishing solution, even if the overflow of
color developer is used as the dilute for preparing the replenishing
solution therefor. This fact can in no way be inferred from the teachings
and disclosure of the conventional techniques. In a continuous processing
method, it is preferred that all or a part of the overflow of the color
developer be directly introduced into one of the subsequent baths such as
the bleaching bath, bleaching-fixing bath or fixing bath, while each of
the concentrated solutions is introduced into the corresponding bath to
substantially prepare each replenishing solution in situ so as to decrease
the amount of the color developer to be discharged. Particularly, when the
overflow of the color developer is finally introduced into the
bleaching-fixing bath and/or the fixing bath, the overflow from each bath
other than developing bath is considered to be a valuable material since
it contains silver ions and, on the other hand, the cost for recovering
the used color developer is substantially saved or entirely eliminated.
Such method is quite preferable in view of reducing cost. Moreover, if all
or a part of the overflow of the color developer is introduced into the
bleaching bath, the overflow from the bleaching bath may further be
introduced into the fixing bath or the bleaching-fixing bath, which also
results in a reduction in cost.
In addition to the aforementioned method for using the overflow from color
developing bath, it is also possible to use the overflow in another manner
which comprises previously admixing the same with concentrate for
preparing a replenishing solution used in a processing process other than
the developing process and supplementing the replenishing solution to the
corresponding processing bath.
In the method of this invention, any amount of the overflow from the bath
for development processing may be added to any one of the subsequent
processing solutions so far as the properties of the bath concerned is not
greatly influenced by the addition thereof. However, the overflow solution
of the color developer is desirably added to any one of the subsequent
baths in an amount of 0.1 to 30 times the volume of the front bath
solution carried over by light-sensitive material treated, preferably 0.2
to 5 times thereof (the amount of the overflow does not include the amount
of color developer entrained with the material). Moreover, the overflow is
suitably used in an amount of 0.2 to 5 times, preferably 0.5 to 3 times
(weight basis) the amount of a concentrated replenishing solution. The
term "overflow solution" as used herein is defined as a solution
discharged out of a tank (or bath) containing the processing solution to
always maintain a constant volume of the corresponding processing solution
when a replenishing solution is continuously or periodically supplied to
the tank. The overflow is in general discharged out of the tank by
utilizing the difference in solution levels or by means of a pump or the
like.
When the overflow is added to an intended processing solution, it is
preferable that the pH of the overflow added in previously adjusted to
that of the corresponding processing both, such as bleaching bath,
bleaching-fixing bath or fixing bath, by the addition of a weak or strong
inorganic or organic acid.
Moreover, the overflow solution from water washing process as the
subsequent process may preferably be used as a part of processing
solutions other than the developer, in addition to the aforementioned
overflow and thus the amount of waste liquor can be further reduced.
The processing method according to the present invention will now be
explained more concretely. However, the following explanation is not
intended to restrict the invention to specific embodiments described. In
the following description, the arrows indicate the direction of flow of
all or a part of the overflow solution.
##STR1##
In the foregoing processes, a stabilizing bath may be disposed behind the
final water washing process according to need. Moreover, it is also
preferable to adopt a method which permits a substantial decrease in the
amount of washing water as disclosed in, for instance, Japanese Patent
Un-examined Publication No. 57-132146 or a so-called "stabilization
processing" as disclosed in, for instance, Japanese Patent Unexamined
Publication No. 57-8543, instead of the foregoing water washing process.
When adopting these water saving processing methods, all or a part of the
overflow solution of the washing water may be introduced into a front bath
such as bleaching-fixing bath or fixing bath.
Each processing bath as used herein will hereunder be explained in more
detail.
Color development bath
The primary aromatic amine type color development agents which can be used
in the color development solution as used herein include conventional ones
widely used in a variety of color photography processes. Examples of these
developers are aminophenolic derivatives and p-phenylenediamine type
derivatives. Preferred are derivatives of p-phenylenediamine and typical
examples thereof include the following compounds simply listed by way of
example:
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: N-ethyl-N-(.beta.-methanesulfonamidoethyl)-3-methyl-4-aminoaniline;
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.-butoxyethylaniline.
These derivatives of p-phenylenediamine may be salts such as sulfates,
hydrochlorides, sulfonates and p-toluenesulfonates. These compounds are
disclosed in, for example, U.S. Pat. Nos. 2,193,015; 2,552,241; 2,566,271;
2,592,364; 3,656,950 and 3,698,525. These primary aromatic amines used as
the developing agent are used in an amount of about 0.1 g to about 20 g
per liter of developing solution and more preferably about 0.5 g to about
10 g.
As is well known, the color developer as used herein can contain
hydroxylamines. Although, the hydroxylamines may be used in the form of
free amines, it is more general to use the same in the form of a
water-soluble salt. Typical examples of such salts include sulfates,
oxalates, chlorides, phosphates, carbonates and acetates The
hydroxylamines may be substituted with substituents or unsubstituted and
may further be substituted with an alkyl group at their nitrogen atom.
The preferred amount of the hydroxylamine added is in the range of from 0
to 10 g per liter of the color developer, more preferably 0 to 5 g. The
hydroxylamine is preferably used in a rather small amount within the range
that the stability of the color developer can be assured.
Moreover, the color developer used in the present invention preferably
contains a preservative, for example, a sulfite, metasulfite or bisulfite
such as sodium sulfite, potassium sulfite, sodium bisulfite, potassium
bisulfite, sodium metasulfite and potassium metasulfite; and adducts of
carbonylsulfite. The amount of the preservative preferably falls within
the range of from 0 to 20 g/l , more preferably 0 to 5 g/l. Similarly, the
preservative is preferably used in a small amount within the range that
the stability of the color developer is maintained.
Other preservatives may also be used in the color developer as used herein
and include aromatic polyhydroxy compounds such as those disclosed in
Japanese Patent Unexamined Publication Nos. 52-49828; 56-47038; 56-32140;
and 59-160142 and U.S. Pat. No. 3,746,544; hydroxyacetones such as those
disclosed in U.S. Pat. No. 3,615,503 and British Patent No. 1,306,176;
.alpha.-aminocarbonyl compounds such as those disclosed in Japanese Patent
Un-examined Publication Nos. 52-143020 and 53-89425; different kinds of
metal salts such as those disclosed in Japanese Patent Un-examined
Publication Nos. 57-44148 and 57-53749; a variety of sugars disclosed in
Japanese Patent Un-examined Publication No. 52-102727; hydroxamic acids
disclosed in Japanese Patent Un-examined Publication No. 52-27638;
.alpha.,.alpha.'-dicarbonyl compounds disclosed in Japanese Patent
Un-examined Publication No. 59-160141; salicylic acids disclosed in
Japanese Patent Un-examined Publication No. 59-180588; alkanol amines
described in Japanese Patent Un-examined Publication No. 54-3532;
poly(alkyleneimines) described in Japanese Patent Un-examined Publication
No. 56-94349; and derivatives of gluconic acid disclosed in Japanese
Patent Un-examined Publication No. 56-75647. These preservatives may be
used in combination according to need. In particular, the preservatives
such as 4,5-dihydroxy-m-benzene disulfonic acid, poly(ethyleneimine) and
triethanolamine are preferably added to the color developer.
The pH value of the color developer as used herein preferably falls within
the range of 9 to 12, more preferably 9 to 11.0. The color developer may
further contain other ingredients of known color developers.
To assure the aforementioned pH value any of a variety of buffering agents
are preferably used. As such buffering agent, there may be used, for
instance, carbonates, phosphates, borates, tetraborates, hydroxybenzoates,
glycine salts, N,N-dimethylglycine salts, leucine salts, norleucine salts,
guanine salts, 3,4-dihydroxyphenylalamine salt, alanine salts,
aminobutyric acid salts, 2-amino-2-methyl-1,3-propanediol salts, valine
salts, proline salts, trishydroxyaminomethane salts and lysine salts. The
carbonates, phosphates, tetraborates and hydroxybenzoates, among others,
are excellent in solubility in the color developer and buffering effect at
a high pH region of 9.0 or more, have no influence such as fogging on the
photographic properties when they are added to the developer, and are in
expensive. Therefore, it is particularly preferred to use these buffering
agents in the color developer as used in the present invention.
Concrete examples of such buffering 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-sulfosalicylate). However, the present invention is not restricted to
these specific compounds.
The amount of the buffering agent added to the color developer is
preferably equal to or more than 0.1 mole/l and the particularly preferred
amount thereof falls within the range of 0.1 mole/l to 0.4 mole/l. It is
not desirable to use an excess amount of buffering agent, since the pH
value of a processing bath to which the overflow is added becomes
undesirably high in such case.
Furthermore, the color developer as used in the present invention may
contain any of various kinds of chelating agents as the suspension agent
for calcium or magnesium ions or for the purpose of improving the
stability of the color developer.
Preferred chelating agents are organic acid compounds and include, for
instance, aminopolycarboxylic acids such as those disclosed in Japanese
Patent Publication Nos. 48-030496 and 44-30232; organophosphonic acids
such as those described in Japanese Patent Un-examined Publication No.
56-97347, Japanese Patent Publication No. 56-39359 and West German Patent
No. 2,227,639; phosphonocarboxylic acids such as those disclosed in
Japanese Patent Un-examined Publication Nos. 52-102726; 53-42730;
54-121127; 55-126241 and 55-65956; and compounds such as those described
in Japanese Patent Unexamined Publication Nos. 58-195845 and 58-203440 and
Japanese Patent Publication No. 53-40900. Typical and non-limitative
examples thereof are as follows:
nitrilotriacetic acid;
diethyleneaminopentaacetic acid;
triethylenetetraminehexaacetic acid;
N,N,N-trimethylenephosphonic acid;
ethylenediamine-N,N,N',N'-tetramethylenephosphonic acid;
1,3-diamino-2-propanol-tetraacetic acid;
trans-cyclohexanediaminetetraacetic acid;
nitrilotripropionic acid;
1,2-diaminopropanetetraacetic acid;
hydroxyethyliminodiacetic acid;
glycol ether diaminotetraacetic acid;
hydroxyethylenediaminetriacetic acid;
ethylenediamineorthohydroxyphenylacetic acid;
2-phosphonobutane-1,2,4-tricarboxylic acid;
1-hydroxyethane-1,1-diphosphonic acid;
N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid.
These chelating agent may be used in combination according to need.
Moreover, the chelating agent is used in an amount sufficient to sequester
metallic ions present in the color developer, which, for example, falls
within the range of from about 0.1 g to 10 g per liter of the developer.
The color developer may also contain a development accelerator, if
necessary.
Examples of such development accelerators include thioether type compounds
such as those disclosed in Japanese Patent Publication Nos. 37-16088;
37-5987; 38-7826; 44-12380 and 45-9019, U.S. Pat. No. 3,813,247 and the
like; p-phenylenediamine type compounds such as those disclosed in
Japanese Patent Un-examined Publication Nos. 52-49829 and 50- 15554;
quaternary ammonium salts such as those disclosed in, for example,
Japanese Patent Un-examined Publication Nos. 50-137726; 56-156826 and
52-43429 and Japanese Patent Publication No. 44-30074; p-aminophenols such
as those disclosed in U.S. Pat. Nos. 2,610,122 and 4,119,462; amine type
compounds such as those described in, for example, U.S. Pat. Nos.
2,494,903; 3,128,182; 4,230,796; 3,253,919; 2,482,546; 2,596,926 and
3,582,346 and Japanese Patent Publication No. 41-11431; polyalkylene
oxides such as those disclosed in, for instance, Japanese Patent
Publication Nos. 37-16088; 42-25201; 41-11431 and 42-23883 and U.S. Pat.
Nos. 3,128,183 and 3,523,501 as well as 1-phenyl-3-pyrazolidones,
hydrazines, meso-ionic compounds, thionic compounds, imidazoles or the
like. Thioether type compounds and 1-phenyl-3-pyrazolidones, among others,
are preferred.
To the color developer used in the present invention, there may be added
any of antifoggants according to need. Examples thereof include alkali
metal halides such as potassium bromide, sodium bromide, potassium iodide
and organic antifoggants. The organic antifoggants include, for example,
nitrogen atom-containing heterocyclic compounds such as benzotriazole,
6-nitrobenzimidazole, 5-nitroisoindazole, 5-methylbenzotriazole,
5-nitrobenzotriazole, 5-chlorobenzotriazole, 2-triazolyl-benzimidazole,
2-thiazolylmethylbenzimidazole and hydroxyazaindolizine; and mercapto
substituted heterocyclic compounds such as 1-phenyl-5-mercaptotetrazole,
2-mercaptobenzimidazole and 2-mercaptobenzothiazole; adenine and mercapto
substituted aromatic compounds such as thiosalicylic acid. Particularly
preferred are nitrogen atom-containing heterocyclic compounds. These
antifoggants may also be incorporated in a color light-sensitive material
so that they are dissolved in a processing solution and accumulated
therein during processing. However, it is preferable that the amount of
the antifoggant accumulated be as low as possible from the viewpoint of
the reduction in the amount of waste liquor.
It is desirable to add a fluorescent whitening agent to the color developer
used in the present invention. Preferred examples of such fluorescent
whitening agents include 4,4'-diamino-2,2'-disulfostilbene type compounds
and the amount thereof is preferably in the range of 0 to 5 g/l, more
preferably 0.1 to 2 g/l.
To the color developer, there may further be added any of a variety of
surfactants, for instance, alkylsulfonic acids, arylsulfonic acids,
aliphatic carboxylic acids and aromatic carboxylic acid, according to
need.
It is preferred that the color developer used in the present invention be
substantially free from benzyl alcohol. That is, if an overflow solution
of the color developer containing benzyl alcohol is recycled to a
bleaching solution or a bleaching-fixing solution, the presence of benzyl
alcohol may cause undesirable staining and the conversion of a cyan dye to
leuco dye. The term "substantially free from" as used herein means that
the benzyl alcohol is present in an amount of not more than 2 ml per liter
of the color developer, preferably not more than 0.5 ml and more
preferably it is not present at all.
The temperature of the color developer used in the present invention during
processing is preferably 20.degree. to 50.degree. C., more preferably
30.degree. to 40.degree. C. The time required for processing a color
light-sensitive material by means of the color developer falls within the
range of from 20 seconds to 10 minutes, more preferably 30 seconds to 5
minutes. The amount of replenishing solution to be added is in the range
of 30 ml to 2000 ml per unit area (square meter) of the light-sensitive
material processed, preferably 30 ml to 1500 ml. From the viewpoint of the
reduction in the amount of waste liquor, the replenishing solution is
preferably supplied in a smaller amount.
Bleaching solution, bleaching-fixing solution, fixing solution
In the bleaching solution or bleaching-fixing solution which can be used in
the method of this invention, the bleaching agent may be, for instance, a
complex of ferric ion, in other words a complex of ferric ion and a
chelating agent such as an aminopolycarboxylic acid, an
aminopolyphosphonic acid or a salt thereof. Examples of the
aminopolycarboxylic acid salts or aminopolyphosphonic acid salts include
alkali metal salts, ammonium salts and water-soluble amine salts of
amino-polycarboxylic acid or aminopolyphosphonic acid. As such alkali
metal, there may be mentioned, for example, sodium, potassium and lithium,
while as the water-soluble amine, there can be mentioned, for example,
alkylamines such as methylamine, diethylamine, triethylamine and
butylamine; alicyclicamines such as cyclohexylamine; arylamines such as
aniline and m-toluidine; and heterocyclic amines such as pyridine,
morpholine and piperidine.
Typical examples of the chelating agents such as aminopolycarboxylic acid,
aminopolyphosphonic acid or a salt thereof include compounds listed below:
ethylenediaminetetraacetic acid;
disodium ethylenediaminetetraacetate;
diammonium ethylenediaminetetraacetate;
tetra(trimethylammonium) ethylenediaminetetraacetate;
tetrapotassium ethylenediaminetetraacetate;
tetrasodium ethylenedaminetetraacetate;
trisodium ethylenediaminetetraacetate;
diethylenetriaminepentaacetic acid;
pentasodium diethylenetriaminepentaacetate;
ethylenediamine-N-(.beta.-oxyethyl)-N,N',N'-triacetic acid;
trisodium ethylenediamine-N-(.beta.-oxyethyl)-N,N',N'-triacetate;
triammonium ethylenediamine-N-(.beta.-oxyethyl)-N,N',N'-triacetate;
propylenediaminetetraacetic acid;
disodium propylenediaminetetraacetate;
nitrilotriacetic acid;
trisodium nitrilotriacetate;
cyclohexanediaminetetraacetic acid;
disodium cyclohexanediaminetetraacetate;
iminodiacetic acid;
dihydroxyethyl glycine;
ethyl ether diaminetetraacetic acid;
glycol ether diaminetetraacetic acid;
ethylenediaminetetrapropionic acid;
phenylenediaminetetraacetic acid;
1,3-diaminopropanol-N,N,N',N'-tetramethylenephosphonic acid;
ethylenediamine-N,N,N',N'-tetramethylenephosphonic acid;
1,3-propylenediamine-N,N,N',N'-tetramethylenephosphonic acid.
It is a matter of course that the invention is not restricted to those
specific chelating agents.
The complex salt of ferric ions may be used as it is or it may be formed in
situ by separately adding a ferric salt such as ferric sulfate, ferric
chloride, ferric nitrate, ammonium ferric sulfate and ferric phosphate;
and a chelating agent such as an aminopolycarboxylic acid, an
aminopolyphosphonic acid and a phosphonocarboxylic acid to a solution. The
complex salt per se may be used independently or in combination; the
complex salts formed in situ by using a ferric salt and a chelating agent
be used alone or in combination; and, moreover, the chelating agents may
also be used in combination. In any case, the chelating agents may be used
in an amount exceeding that required to form a desired amount of ferric
ion complex salt. Among complexes of ferric ion preferred are complexes of
ferric ion-aminocarboxylic acid and the amount thereof used is in the
range of from 0.01 to 1.0 mole/l, preferably 0.05 to 0.50 mole/l.
In addition, a bleaching accelerator may be optionally added to the
bleaching solution or bleaching-fixing solution as used herein Concrete
examples of such useful bleaching accelerators include compounds having
mercapto groups or disulfide groups such as those disclosed in, for
instance, U.S. Pat. No. 3,893,858; West German Patent Nos. 1,290,812 and
2,059,988; Japanese Patent Un-examined Publication Nos. 53-32736;
53-57831; 53-37418; 53-65732; 53-72623; 53-95630; 53-95631; 53-104232;
53-124424; 53-141623 and 53-28426 and Research Disclosure No. 17129 (July,
1978); thiazolidine derivatives such as those disclosed in Japanese Patent
Unexamined Publication No. 50-140129; thiourea derivatives disclosed in
Japanese Patent Publication No. 45-8506, Japanese Patent Un-examined
Publication Nos. 52-20832 and 53-32735 and U.S. Pat. No. 3,706,561;
iodides disclosed in West German Patent No. 1,127,715 and Japanese Patent
Un-examined Publication No. 58-16235; polyethylene oxides disclosed in
West German Patent Nos 966,410 and 2,748,430; polyamine compounds
disclosed in Japanese Patent Publication No. 45-8836; as well as compounds
disclosed in Japanese Patent Unexamined Publication Nos. 49-42434;
49-59644; 53-94927; 54-35727; 55-26506 and 58-163940 and iodide and
bromide ions. Among others, compounds having mercapto group(s) or
disulfide group(s) are preferred examples because of their strong
acceleration effect and particularly preferred compounds are those
disclosed in U.S. Pat. No. 3,893,858, West German Patent No. 1,290,812 and
Japanese Patent Un-examined Publication No. 53-95630.
In addition to the aforementioned ingredients, the bleaching solution or
bleaching-fixing solution as used herein may also contain a rehalogenation
agent, for example, bromides such as potassium bromide, sodium bromide and
ammonium bromide; or chlorides such as potassium chloride, sodium chloride
and ammonium chloride; or iodides such as ammonium iodide. Moreover, to
these processing solutions as used herein, there may optionally be added
at least one member selected from the group consisting of inorganic acid,
organic acid and an alkali metal or ammonium salts thereof having pH
buffering effect, for example, boric acid, borax, sodium metaborate,
acetic acid, sodium acetate, sodium carbonate, potassium carbonate,
phosphorous acid, phosphoric acid, sodium phosphate, citric acid, sodium
citrate and tartaric acid; or a anticorrosive such as ammonium nitrate and
guanidine.
The fixing agent used in the fixing solution or bleaching-fixing solution
as used herein may be a known one, for example, water-soluble silver
halide solvents which include thiosulfates such as sodium thiosulfate,
ammonium thiosulfate; thiocyanates such as sodium thiocyanate, ammonium
thiocyanate; thioether compounds such as ethylenebisthioglycolic acid,
3,6-dithia-1,8-octanediol; and thioureas. These fixing agents may be used
singly or in combination. In addition, it is also possible to use a
specific bleaching-fixing solution comprising a combination of a fixing
agent disclosed in Japanese Patent Un-examined Publication No. 55-155354
with a large amount of a halide such as potassium iodide, or the like. In
the present invention, a thiosulfate, in particular ammonium thiosulfate
is preferably used.
The amount of the fixing agent preferably falls within the range of from
0.3 to 2 moles per liter of the processing solution, more preferably from
0.5 to 1.0 mole.
The preferred pH range of the bleaching-fixing solution or fixing solution
as used herein is 3 to 10 and the particularly preferred range is 5 to 9.
This is because, if the pH value is less than the lower limit, the
desilvering property of these solutions is improved but the solutions are
deteriorated and the conversion of a cyan dye to leuco dye is promoted. On
the other hand, if the pH exceeds the aforementioned upper limit, the
desilvering rate becomes low and stains are liable to form during
processing.
In order to adjust the pH of these solutions, it is also possible to add a
compound such as hydrochloric acid, sulfuric acid, nitric acid, acetic
acid, bicarbonates, ammonia, caustic potash, caustic soda, sodium
carbonate or potassium carbonate, according to need.
As regards the bleaching-fixing solution, it may also contain, for
instance, a variety of fluorescent brighteners, anti-foaming agents,
surfactant, polyvinyl pyrrolidone or organic solvents such as methanol.
The bleaching-fixing solution or fixing solution used in the present
invention contains a compound releasing sulfite ions, as the preservative,
such as sulfites (e.g., sodium sulfite, potassium sulfite, ammonium
sulfite); bisulfites (e.g., ammonium bisulfite, sodium bisulfite,
potassium bisulfite) and metabisulfites (e.g., potassium metabisulfite,
sodium metabisulfite, ammonium metabisulfite). These compounds are
preferably present in the solutions in an amount of about 0.02 to 0.50
mole/l (converted to bisulfite ions), more preferably 0.04 to 0.40 mole/l.
A sulfite is in general used as the preservative, but other preservatives
such as ascorbic acid, carbonylbisulfite adducts or a carbonyl compound
may also be used.
In addition, buffering agents, fluorescent brighteners, chelating agents,
anti-fungus agents or the like may be added to the solutions according to
need.
The washing process of the method according to the present invention will
now be explained below. In the method of this invention, a simplified
processing method may be adopted, in which only a so-called "stabilization
processing" is included instead of a common "water washing process" while
eliminating a substantial washing process. The term "water washing
process" herein is thus used in a broad sense inclusive of the
aforementioned embodiments.
It is difficult to clearly define the amount of washing water in the
washing processing since it varies depending on the number of baths
included in a multistage counterflow washing system and the amount of the
front bath compounds entrained with the light-sensitive material treated.
However, the amount thereof is defined in the present invention so that
the concentration of the components of the bleaching-fixing solution in
the final washing bath is not more than 1.times.10.sup.-4. For example,
when a three stage (three tank) counterflow washing system is adopted, the
amount of washing water is preferably at least about 1000 ml per unit area
(square meter) of the light-sensitive material and the particularly
preferred amount is not less than 5000 ml. While if a water saving
processing method is selected, it is preferable to use 100 to 1000 ml of
washing water per unit area (1 m.sup.2) of light-sensitive material
processed.
The temperature of the washing water is in the range of 15.degree. to
45.degree. C., particularly 20.degree. to 35.degree. C.
The washing water may contain various known compounds for the purposes of,
for instance, preventing the formation of precipitates or stabilizing the
washing water. Such compounds, optionally addable to the washing water,
include chelating agents such as inorganic phosphoric acids,
aminopolycarboxylic acid and organic phosphonic acids; bactericides or
anti-fungus agents for inhibiting the propagation of a variety of
bacteria, algae or mold, such as those disclosed in J. Antibact. Antifung.
Agents, 1983, 11-5, 207-223 and those disclosed in "Bokin Bobai no Kagaku
(Chemistry for inhibition of bacteria and fungi)", Hiroshi Horiguchi;
metal salts represented by magnesium salts and aluminum salts; alkali
metal salts and ammonium salts; or agents such as surfactants for
preventing unevenness or for reducing drying load. Moreover, compounds
such as those disclosed in, for instance, Phot. Sci. Eng., 1965, 6,
344-359, (L. E. West) may be added to the washing water.
The method according to the present invention is particularly effective in
the case where a chelating agent, a bactericide and an anti-fungus agent
are added to the washing water and it is intended to substantially save
the amount of washing water by adopting a multistage counterflow washing
system including at least two baths. Moreover, the method of this
invention can also be effectively carried out when a multistage
counterflow stabilization process (so-called stabilization processing)
disclosed in Japanese Patent Unexamined Publication No. 57-8543 is
utilized instead of the usual water washing process. In these cases, the
concentration of the components contained in the bleaching-fixing solution
should be in the range of not more than 5.times.10.sup.-2, preferably at
most 1.times.10.sup.-2, in the final washing bath.
On the aforementioned stabilizing bath, various kinds of compounds other
than the foregoing additives are added for the purpose of the
stabilization of images. Typical examples of such compounds include a
variety of buffering agents for adjusting the pH value of membranes of the
processing machine (e.g., to pH 3 to 8), such as a combination of borates,
metaborates, borax, phosphates, carbonates, potassium hydroxide, sodium
hydroxide, aqueous ammonia, memocarboxylic acids, dicarboxylic acids, and
polycarboxylic acids; and aldehydes such as formalin. In addition to such
compounds, chelating agents such as inorganic phosphoric acids,
aminopolycarboxylic acids, organic phosphonic acids, aminopolyphosphonic
acids, and phosphonocarboxylic acids; bactericides such as thiazoles,
isothiazoles, halogenated phenols, sulfanylamide and benzotriazole;
surfactants; fluorescent brightener; and film hardening agents may also be
added to the washing water. Two or more of them may be used in
combination, for the same or different purposes.
In view of improvement of image preservability, it is preferred to use any
of a variety of ammonium salts such as ammonium chloride, ammonium
nitrate, ammonium sulfate, ammonium phosphate, ammonium sulfite and
ammonium thiosulfate, as the agent for adjusting pH value of the
processing machine.
When the amount of washing water is substantially saved as is explained
above, it is preferred, for the purpose of reducing the amount of solution
discharged, that all or a part of the overflow of the washing water be
introduced into a front bath such as the bleaching-fixing bath or fixing
bath.
If the water washing process is continuously carried out, each replenishing
solution is added to the corresponding processing bath so as to prevent
change in bath composition. This results in the formation of final
products having uniform properties. The amount of each replenishing
solution may be reduced to half or less of the standard amount thereof for
the purposes of, for instance, reducing cost.
According to need, each processing bath may be equipped with a heater, a
temperature sensor, a level sensor, a circulation pump, a filter, any of a
variety of floating covers, various kinds of squeezes, a nitrogen agitator
and an air agitator.
The method according to the present invention can be applied to any
processing method so far as the processing method utilizes a color
developer. For example, the method can be applied to the processing of
color papers, color reversal papers, color positive films, color negative
films and color reversal films.
Silver halide emulsion for use in this invention contains silver bromide,
silver chlorobromide, or silver chloride each substantially containing no
silver iodide. A preferred silver halide is silver chlorobromide
containing from 2 mol % to 99 mol % silver chloride.
In the case of performing quick processing and low replenisher processing,
a silver chlorobromide emulsion containing at least 60 mol % silver
chloride or a silver chloride emulsion is preferred, and those containing
from 80 mol % to 100 mol % of silver chloride are particularly preferred.
Also, in the case of requiring high sensitivity and restraining the
formation of fog as low as possible during the production, storage and/or
processing of color photographic material, a silver chlorobromide emulsion
or an iodobromide emulsion each containing at least 50 mol % silver
bromide or a silver bromide emulsion is preferred and also it is more
preferred that the content of silver bromide is higher than 70 mol %. When
the content of silver bromide is over 90 mol %, it becomes difficult to
effectively perform quick processing for the color photographic materials
but by employing a development accelerating means of using a development
accelerator such as a silver halide solvent, a fogging agent, a developing
agent, etc., as will be described hereinafter, the development process can
be quickened to some extent without being restricted by the content of
silver bromide and such a case is sometimes preferred.
The silver halide grains for use in this invention may have a regular
crystal form such as cubic, octahedral, dodecahedral, tetradecahedral,
etc., a mixture thereof, an irregular crystal form such as spherical,
etc., or a composite form of these crystal forms. Also, the silver halide
grains may be tabular grains and in this case, a tabular grain silver
halide emulsion wherein tabular silver halide grains having an aspect
ratio (length/thickness) of at least 5 (that is, at least 5/1), and
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