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Description  |
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FIELD OF THE INVENTION
This invention relates to a method for rapidly and stably processing a
color light-sensitive material containing light-sensitive silver halide
and couplers, such as a color paper. More particularly, it relates to a
method for processing a color photographic material which makes it
feasible to achieve image formation and desilvering in a reduced
processing time. It also relates to a method for processing a color
photographic material which provides a color image excellent in dye image
stability.
BACKGROUND OF THE INVENTION
Photographic processing of silver halide color photographic materials
basically comprises development (in the case of color reversal materials,
color development is preceded by black-and-white first development),
desilvering, and washing. Desilvering comprises bleach and fixing or
combined bleach-fix (blix). Processing further includes supplementary
steps, such as stabilization, prebath processing preceding each step, and
stopping. In color development, exposed silver halide is reduced by a
color developing agent to form silver and halogen ions. Simultaneously,
the thus oxidized color developing agent reacts with a coupler to form a
dye. Therefore, because a large quantity of a silver halide color
photographic material is continuously processed, halogen ion accumulate in
the developing solution.
Recently, reduction in the rate of replenishment for the purpose of saving
resources and reduction of environmental pollution has been extensively
studied. However, mere reduction of replenishment of a developing solution
gives rise to a problem that substances dissolved from a light-sensitive
material, particularly iodide ion or bromide ion which are each strong
development inhibitors, accumulate and lessen development activity. This
results in a decrease in processing rapidity. In order to reduce the
accumulation of iodide or bromide ion, use of a silver halide
light-sensitive material having a high silver chloride content to thereby
secure rapid processing as disclosed in JP-A-58-95345, JP-A-59-232342,
JP-A-61-70552, W087-04534, and JP-A-1-105948 (the term "JP-A" as used
herein means an "unexamined published Japanese patent application") has
been proposed. Use of such a high silver chloride light-sensitive material
is considered an effective means for making rapid development processing
feasible. While a shortening of color development time has thus been
steadily realized, the time required for bleach-fix subsequent to color
development has not changed so that the overall processing time has not
been greatly reduced.
JP-A-1-196044 discloses a processing method in which color development is
completed in 25 seconds or less, and the overall processing time including
the times for bleach-fix and washing is within 2 minutes. In this method,
however, light-sensitive materials are not sufficiently desilvered when
continuously processed due to such a short time for bleach-fix. Thus an
image of clear color separation is not obtained. Further, it turned out
that when bleach-fix is completed within a very short time of 30 seconds
or less, the resulting image is stained with time, particularly under
light irradiation at high humidity.
Reduction in overall processing time of color photographic materials is a
present day object that one skilled in the art has been eager to
accomplish. Namely, greatly speeding up each step involved from color
development through drying is required. Under the present situation,
however, if color development and bleach-fix is each effected in an
extremely short time, continuous processing is easily accompanied by
desilvering insufficiency, and the resulting dye image has deteriorated
preservability.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method for processing a
color photographic light-sensitive material which achieves ultra-rapid
development and also makes it possible to reduce the time required for the
subsequent bleach-fix and washing.
Another object of the present invention is to provide a method for
processing a color photographic material which provides a dye image having
excellent long-term preservation stability even when bleach-fix is
completed in a short time.
Research has been conducted on ultra-rapid processing of a light-sensitive
material comprising silver halide having a high silver chloride content by
appropriately selecting a p-phenylenediamine derivative and/or by changing
the film thickness and the degree of swelling of the light-sensitive
material. As a result, it has been unexpectedly found that rapid
processing can be achieved in all of the steps including color
development, bleach-fix, and washing, and an image excellent with
long-term preservation stability can be obtained even through rapid
desilvering and rapid washing. This is achieved by subjecting a high
silver chloride light-sensitive material to color development with a
hydrophilic p-phenylenediamine derivative as a developing agent and then
passing this material to a bleaching or bleach-fix bath with the amount of
the color developing agent present in the light-sensitive material being
controlled below a certain level.
That is, the above objects of the present invention are accomplished by a
method for processing a silver halide color photographic light-sensitive
material comprising subjecting an imagewise exposed silver halide color
light-sensitive material having a silver chloride content substantially of
90 mol % or more to color development and then subjecting the color
developed material to bleach or bleach-fix, wherein the color development
is effected with a color developing solution containing a hydrophilic
p-phenylenediamine derivative and substantially no benzyl alcohol at a
temperature of 30.degree. C. or higher for a period of 20 seconds or less,
and wherein the method comprises introducing the color development
processed silver halide color light-sensitive material into a bleaching or
bleach-fix bath with the amount of a color developing agent in the film of
the light-sensitive material being controlled to 1 mmol/m.sup.2 or less,
preferably 0.8 mmol/m.sup.2 or less, and more preferably 0.6 mmol/m.sup.2
or less but 0.3 mmol/m.sup.2 or more, and desilvering is completed within
30 seconds, and preferably within 20 seconds.
In the present invention, the color developing solution also preferably
contains substantially no hydroxylamine and/or no sulfite ion. The color
developing agent which can be used in the present invention has at least
one hydrophilic group and preferably has a calculated logP value
(hereinafter defined) of not more than 1.0.
The amount of color developing solution replenisher is preferably not more
than 120 ml, and more preferably from 15 to 60 ml, per m.sup.2 of the
light-sensitive material. The amount of replenisher of a bleach-fix
solution, a washing solution or a stabilizing solution is preferably not
more than 3 times the amount of the carry-over from the respective
preceding bath.
The terminology "developing time" as used herein means the time during
which a light-sensitive material is retained in a developing solution.
The terminology "substantially no benzyl alcohol" as used herein means that
benzyl alcohol is not present in as a large a quantity as has been
conventionally used. Taking the objects of the present invention into
consideration, a suitable concentration of benzyl alcohol in the
developing solution is not more than 8 ml/l, preferably not more than 5
ml/l, and more preferably from 0 up to 3 ml/l. The presence of a small
amount of benzyl alcohol in a developing solution is sometimes favorable
for achieving ultra-rapid processing.
DETAILED DESCRIPTION OF THE INVENTION
In general, the rate of color development varies depending on the kind of
p-phenylenediamine derivative used as a color developing agent. A color
developing agent having a hydrophobic group as an N-substituent, such as
4-amino-3-methyl-N,N-diethylaniline salts and
4-amino-3-methyl-N-ethyl-N-methoxyethylaniline salts, readily distributes
itself in an oil droplet phase containing couplers, etc. to show enhanced
developing performance and has therefore been regarded advantageous for
short time development (see U.S. Pat. Nos. 3,656,950, 3,656,925, and
4,035,188). On the other hand, where a color developing agent having a
hydrophilic group as an N-substituent, such as
4-amino-3-methyl-N-ethyl-N-.beta.-methanesulfonamidoethylaniline salts and
4-amino-3-methyl-N-ethyl-N-.beta.-hydroxyethylaniline salts, is employed,
benzyl alcohol has been used in combination to accelerate the distribution
of the color developing agent into the oil droplet phase to thereby
accelerate color development. In other words, in order to obtain
sufficient image density, a large amount of a color developing agent
should be maintained in the light-sensitive material until it is
introduced into a bleach-fix bath. However, if color development is
carried out with a color developing solution having the above-described
hydrophobic group in a short time of within 20 seconds, development is
retarded to a degree when increases towards the lowermost layer of the
light-sensitive material. Thus an image having an extremely poor color
balance is obtained. Addition of a large amount of benzyl alcohol to a
developing solution increases the color density of the uppermost emulsion
layer, while the color density of the lowermost emulsion layer remains
unchanged, rather resulting in destroyed color balance. It also turned out
that, when a light-sensitive material is bleach-fixed for a short time of
30 seconds or less while a color developing agent is present therein in a
usual amount, uneven processing due to partial desilvering insufficiency
occurs. It was ascertained that such processing unevenness becomes even
greater in the presence of a large amount of benzyl alcohol. It was
further found that the resulting image shows an abnormal increase in stain
density when preserved under light irradiation at high humidity.
In order to solve these problems, extensive investigations were conducted
and, as a result, it has been found that an image free from unevenness due
to desilvering insufficiency and light stain can be obtained even with a
bleach-fix of 30 seconds or less by using, contrary to conventional
knowledge, a hydrophilic color developing agent and by reducing the amount
of a color developing agent taken up into the light-sensitive material to
be bleach-fixed to 1 mmol/m.sup.2 or less (preferably 0.6 mmol/m.sup.2 or
less). Reduction of the amount of color developing agent in the
light-sensitive material can be achieved, for example, by decreasing the
thickness of the swollen light-sensitive material (this can be done by,
for example, controlling the amount of a hydrophilic binder, e.g.,
gelatin, and the amount of hardening agent), by washing the color
development processed light-sensitive material with water or immersing the
color development processed light-sensitive material in water which is
neutral to acidic or in a neutral or acidic buffer solution (preferably
having a pH ranging from 3 to 7) to remove the color developing agent, or
by reducing the amount of high-boiling organic solvent used as a
dispersing medium for organic materials (preferably 2 g/m.sup.2 or less,
more preferably 0.6 to 1.8 g/m.sup.2). While it is acceptable for the
developed light-sensitive material to be treated with water, etc. to
remove the color developing agent therefrom and then subjecting the
material to a bleach-fix, such a method is not favorable because of the
increase in number of baths and the increase in processing time. Further,
it is preferred that the amount of a color developing agent in the
light-sensitive material is 0.3 mmol/m.sup.2 or more. If the amount is
less than 0.3 mmol/m.sup.2, a sufficient image density cannot be obtained
in a short-time development as in the present invention.
For the purpose of achieving ultra-rapid development within 20 seconds, it
was found preferred to rapidly supply a color developing agent to the
lowermost layer, i.e., to use a color developing agent which is hardly
trapped by an oil droplet phase and exhibits high diffusibility, and also
to use substantially no benzyl alcohol which accelerates distribution of a
color developing agent into the oil droplet phase. Considering that a
large amount of benzyl alcohol has been believed useful to speed up color
development and has been actually employed for that purpose, the
above-described behavior in ultra-rapid color development is utterly
unexpected. These means for rapid development are also effective in the
above-described rapid bleach-fix as well, and speeding up of each
processing step can be accomplished only by the present invention. Thus,
the present invention makes it feasible to accomplish ultra-rapid
processing throughout all processing steps.
In the present invention, since the amount of a color developing agent
present in the film of a light-sensitive material is reduced, the rate of
replenishment in subsequent steps, i.e., bleach-fix and washing, during
continuous processing can now be greatly reduced.
As stated above, the present invention simultaneously achieves a reduction
in rate of replenishment in each processing step along with ultra-rapid
processing.
A color light-sensitive material contains a hydrophilic binder, such as
high polymeric compounds, e.g., gelatin and polyacrylamide. The swell
characteristics of the film in a processing solution can be changed by
appropriately selecting the kind and amount of the binder or hardening
agent therefor used in the light-sensitive material. The thickness of the
swollen film is preferably 18 .mu.m or less, and more preferably 6 to 15
.mu.m. In order for a processing solution to penetrate rapidly into a
light-sensitive material, the light-sensitive material preferably has a
swell time (time required for the film swell to 80% of the maximum swollen
film thickness as measured in a color developing solution with a
conventional swelling meter) of 15 seconds or less and has a maximum
swollen film thickness of 20 .mu.m or less. By control of the swell
characteristics, residual amounts of various components in the
light-sensitive material can be reduced, and these residual components can
be rapidly dissolved out of the film. Additionally, the drying load can be
greatly diminished.
Effective color developing agents which can be used in the present
invention preferably have a hydrophilicity-imparting group and a logP
value of not more than 1.0. The symbol "P" is the calculated partition
coefficient of a chemical substance, which is the proportion of
distribution of the dissolved chemical substance between two phases
comprising water (aqueous phase) and a substantially water-incompatible
liquid (oily phase). The logP value used in the present invention was
calculated by the method described in JP-A-64-56625, JP-A-64-61431, and a
preprint for lectures of The 9th Information Chemistry Conference (Oct.,
27, 1986), pp. 20-23.
Illustrative but non-limiting examples of the effective color developing
agents are compounds represented by formula (I) shown below, and
preferably the compounds of formula (I) have a logP value of 1.0 or less.
##STR1##
wherein R.sub.1 and R.sub.2 each represents a substituted or unsubstituted
alkyl group; and R.sub.3, R.sub.4, R.sub.5, and R.sub.6 each represents a
hydrogen atom, a substituted or unsubstituted alkyl group, a substituted
or unsubstituted alkoxy group, a sulfo group, or a carboxyl group; or
R.sub.1 and R.sub.2 can combine to form a 5- to 7-membered
nitrogen-containing heterocyclic ring; at least one of R.sub.1, R.sub.2,
R.sub.3, R.sub.4, R.sub.5, and R.sub.6 represents a substituted alkyl or
alkoxy group having a water solubility-imparting group.
In formula (I), examples of water-solubility-imparting groups typically
include a hydroxyalkyl group having from 2 to 4 carbon atoms, a
methanesulfonamidoalkyl group having from 2 to 4 carbon atoms in the alkyl
moiety thereof, --C.sub.2 H.sub.4 CO.sub.2 H, and --C.sub.2 H.sub.4
SO.sub.3 H. Since the stored as a free amine, generally a salt of an
inorganic or organic acid is produced and stored so that a free amine is
formed when adding at the processing. Examples of inorganic or organic
acids for salt-forming the compounds of formula (I) include hydrochloric
acid, sulfuric acid, nitric acid, phosphoric acid, p-toluenesulfonic acid,
methansulfonic acid, and naphthalene-1,5-diphosphonic acid.
Specific but non-limiting examples of the compounds represented by formula
(I) are shown below. The values in the parentheses denote logP values.
1) 4-Amino-3-methyl-N-ethyl-N-.beta.-hydroxyethylaniline salt (0.807)
2) 4-Amino-3-methyl-N-ethyl-N-(3-hydroxypropyl)aniline salt (0.848)
3) 4-Amino-N-ethyl-N-.beta.-hydroxyethylaniline salt (0.492)
4) 4-Amino-3-methyl-N-ethyl-N-.beta.-methanesulfonamidoethylaniline salt
(0.869)
5) 4-Amino-3-.beta.-hydroxyethyl-N,N-diethylaniline salt (0.942)
6) 4-Amino-3-.beta.-methanesulfonamidoethyl-N,N-diethylaniline salt (0.673)
7) 4-Amino-N,N-di-.beta.-hydroxyethylaniline salt (-0.435)
8) 4-Amino-3-methyl-N-ethyl-N-carboxyethylaniline salt (-1.432)
9) 4-Amino-3-methoxy-N-ethyl-N-.beta.-hydroxyethylaniline salt (0.381)
10) 4-Amino-3-methyl-N-ethyl-N-.beta.-methanesulfonamidobutylaniline salt
(0.758)
These compounds may be used either individually or as a combination of two
or more thereof.
The color developing agent is preferably used in an amount of from 1.0 to
60 g/l, and more preferably from 2.0 to 30 g/l. For completing development
in a short time, the developing temperature is preferably 30.degree. C. or
higher.
It is also more preferable to use a developing solution containing
substantially no sulfite ion. In addition to serving as a preservative for
a developing agent, sulfite ion has the effect of dissolving silver halide
and the effect of reducing dye formation efficiency on reacting with an
oxidation product of a developing agent. These effects of a sulfite ion
appear to be one of the causes of an increase in variation of the
photographic characteristics accompanying continuous processing. The
terminology "substantially no sulfite ion" as used herein means that the
amount of sulfite ion is preferably not more than 3.0.times.10.sup.-3
mol/l, and more preferably zero. Note that the sulfite ion as above
referred to excludes the use of a trace amount of sulfite ion as an
antioxidant in a processing kit containing a concentrated developing agent
before preparation of the developing solution.
In addition to no substantial sulfite ion being present, the developing
solution preferably contains substantially no hydroxylamine as well. This
is because hydroxylamine not only functions as a preservative for a
developing solution but has intrinsic silver development activity.
Therefore, variation in the hydroxylamine amount appears to greatly
influence the photographic characteristics. The terminology "substantially
no hydroxylamine" as used herein means that the amount of hydroxylamine is
preferably not more than 5.0.times.10.sup.-3 mol/l, and more preferably is
zero.
Accordingly, the developing solution preferably contains an organic
preservative instead of the above-mentioned hydroxylamine or sulfite ion.
Organic preservatives which can be used are organic compounds capable of
reducing the rate of deterioration of the aromatic primary amine color
developing agent, i.e., organic compounds having the function of
preventing oxidation, e.g., air oxidation of a color developing agent.
Particularly effective organic preservatives are hydroxylamine derivatives
(exclusive of hydroxylamine, hereinafter the same), hydroxamic acids,
hydrazines, hydrazides, phenols, .alpha.-hydroxyketones,
.alpha.-aminoketones, saccharides, monoamines, diamines, polyamines,
quaternary ammonium salts, nitroxyl radicals, alcohols, oximes, diamide
compounds, and condensed cyclic amines. Examples of these organic
preservatives are described, e.g., in JP-A-63-4235, JP-A-63-30845,
JP-A-63-21647, JP-A-63-44655, JP-A-63-53551, JP-A-63-43140, JP-A-63-56654,
JP-A-63-58346, JP-A-63-43138, JP-A-63-146041, JP-A-63-44657,
JP-A-63-44656, U.S. Pat. Nos. 3,615,503 and 2,494,903, JP-A-52-143020, and
JP-B-30496 (the term "JP-B" as used herein means an "examined Japanese
patent publication").
If desired, the developing solution may further contain, as a preservative,
various metals described in JP-A-57-44148 and JP-A-57-53749, salicylic
acid derivatives described in JP-A-59-180588, alkanolamines described in
JP-A-54-3532, polyethyleneimines described in JP-A-56-94349, aromatic
polyhydroxyl compounds described in U.S. Pat. No. 3,746,544, etc. In
particular, alkanolamines, e.g., triethanolamine, dialkylhydroxylamines,
e.g., diethylhydroxylamine, hydrazine derivatives, or aromatic
polyhydroxyl compounds are preferred as preservatives.
Particularly preferred organic preservatives are hydroxylamine derivatives
and hydrazine derivatives (i.e., hydrazines and hydrazides). Specific
examples of these organic preservatives and their use are described in
JP-A-1-97953, JP-A-1-186939, JP-A-1-186940, and JP-A-1-187557.
To improve the stability of the color developing solution which leads to
improved stability of continuous processing, it is more preferable to use
a combination of the above-described hydroxylamine derivative or hydrazine
derivative with an amine. Examples of suitable amines to be used in
combination therewith include cyclic amines as described in
JP-A-63-239447, the amines described in JP-A-63-128340, and the amines
described in JP-A-1-186939 and JP-A-1-187557.
The color developing solution to be used in the present invention
preferably contains 3.5.times.10.sup.-3 to 3.0.times.10.sup.-1 mol/l, and
particularly from 1.times.10.sup.-2 to 2.times.10.sup.-1 mol/l, of
chloride ion. If the chloride ion concentration is more than
3.times.10.sup.-1 mol/l, development tends to be retarded, which is
unfavorable for accomplishing the object of the present invention of
achieving rapid processing and obtaining a high maximum density. A
chloride ion concentration less than 3.5.times.10.sup.-3 mol/l is
unfavorable for fog prevention.
Also, the color developing solution to be used in the present invention
preferably contains from 5.times.10.sup.-6 to 1.0.times.10.sup.-3 mol/l,
and particularly from 3.0.times.10.sup.-5 to 5.times.10.sup.-4 mol/l, of
bromide ion. A bromide ion concentration exceeding 1.times.10.sup.-3 mol/l
retards development, and maximum density and sensitivity are reduced. With
a bromide ion concentration of less than 1.0.times.10.sup.-5 mol/l, fog
cannot be sufficiently prevented.
Chloride and bromide ions may be directly added to a developing solution or
may be supplied by dissolution from a light-sensitive material during
development processing. In the former case, suitable chloride ion sources
include sodium chloride, potassium chloride, ammonium chloride, lithium
chloride, nickel chloride, magnesium chloride, manganese chloride, calcium
chloride, and cadmium chloride, with sodium chloride and potassium
chloride being preferred. The chloride ion may also be supplied by a
fluorescent brightening agent incorporated into a developing solution.
Suitable bromide ion sources include sodium bromide, potassium bromide,
ammonium bromide, lithium bromide, calcium bromide, magnesium bromide,
manganese bromide, nickel bromide, cadmium bromide, cerium bromide,
thallium bromide, with potassium bromide and sodium bromide being
preferred.
Where a chloride and a bromide ion are dissolved out from a light-sensitive
material, they may be supplied either from the emulsions or other
materials.
The color developing solution which can be used in the present invention
preferably has a pH between 9 and 12, and more preferably between 9 and
11.0.
The color developing solution also may contain various known additives.
For example, various buffering agents are preferably used to maintain the
above-recited pH range. Examples of suitable buffering agents include
carbonates, phosphates, borates, tetraborates, hydroxybenzoic acid salts,
glycine salts, N,N-dimethylglycine salts, leucine salts, norleucine salts,
guanine salts, 3,4-dihydroxyphenylalanine salts, alanine salts,
aminobutyric acid salts, 2-amino-2-methyl-1,3-propanediol salts, valine
salts, proline salts, trishydroxyaminomethane salts, and lysine salts. In
particular, carbonates, phosphates, tetraborates, and hydroxybenzoates are
preferred because they have excellent solubility and buffering ability in
a high pH range of 9.0 or more, do not adversely influence the
photographic performance (e.g., fog) when added to a color developing
solution, and are inexpensive.
Specific but non-limiting examples of suitable buffering agents are sodium
carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate,
sodium tertiary phosphate, potassium tertiary phosphate, sodium secondary
phosphate, potassium secondary 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).
The buffering agent is preferably present in the color developing solution
in an amount of 0.1 mol/l or more, and more preferably from 0.1 to 0.4
mol/l.
Various chelating agents can be used in the color developing solution to
prevent precipitation of calcium or magnesium or to improve the stability
of the developing solution. Examples of suitable chelating agents include
nitrilotriacetic acid, diethylenetriaminepentaacetic acid,
ethylenediaminetetraacetic acid, N,N,N-trimethylenephosphonic acid,
ethylenediamine-N,N,N',N'-tetramethylenesulfonic acid,
trans-cyclohexanediaminetetraacetic acid, 1,2-diaminopropanetetraacetic
acid, glycol ether diaminetetraacetic acid, ethylenediamine
o-hydroxyphenylacetic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid,
1-hydroxyethylidene-1,1-diphosphonic acid, and
N'N'-bis(2-hydroxybenzyl)ethylenediamine-N'N'-diacetic acid. These
chelating agents may be used either individually or as a combination of
two or more thereof.
The chelating agent is present in an amount sufficient to sequester
metallic ions in the color developing solution, usually in an amount of
from about 0.1 g to about 10 g per liter.
If desired, a developing accelerator may be added to a color developing
solution. Examples of suitable developing accelerators include thioether
compounds as described 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 as described in JP-A-52-49829 and
JP-A-50-15554; quaternary ammonium salts as described in JP-A-50-137726,
JP-B-44-30074, JP-A-56-156826, and JP-A-52-43429; amine compounds as
described in U.S. Pat. Nos. 2,494,903, 3,128,182, 4,230,796, and
3,253,919, JP-B-41-11431, and U.S. Pat. Nos. 2,482,546, 2,596,926, and
3,582,346; polyalkylene oxides as described 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; and imidazoles.
If desired, an antifoggant may also be added to the color developing
solution. Examples of suitable antifoggants include alkali metal halides,
e.g., sodium chloride, potassium bromide and potassium iodide; and organic
antifoggants. Typical examples of suitable organic antifoggants are
nitrogen-containing heterocyclic compounds, e.g., benzotriazole,
6-nitrobenzimidazole, 5-nitroisoindazole, 5-methylbenzotriazole,
5-nitrobenzotriazole, 5-chlorobenzotriazole, 2-thiazolylbenzimidazole,
2-thiazolylmethylbenzimidazole, indazole, hydroxyazaindolizine, and
adenine.
The color developing solution preferably contains a fluorescent brightening
agent. Examples of suitable fluorescent brightening agents include
4,4'-diamino-2,2'-disulfostilbene compounds. The fluorescent brightening
agent is used in an amount of up to 5 g/l, and preferably from 0.1 to 4
g/l.
If desired, various surface active agents, such as alkylsulfonic acids,
arylsulfonic acids, aliphatic carboxylic acids, and aromatic carboxylic
acids, may also be present in the color developing solution.
Where the rate of replenishment is reduced, it is preferable to prevent
evaporation and air oxidation of the color developing solution by
decreasing the open area of the processing tank in contact with air. The
open area of the processing tank can be expressed in terms of the opening
ratio calculated by dividing the contact area (cm.sup.2) of the processing
solution with air by the volume (cm.sup.3) of the processing solution. The
opening ratio as defined above is preferably not more than 0.1, and more
preferably between 0.001 and 0.05.
The opening ratio of the processing tank can be so adjusted by, for
example, putting a barrier, such as a floating cover, on the liquid
surface, using a movable cover as described in JP-A-62-241342, or
utilizing slit development processing as described in JP-A-63-216050.
Reduction in the opening ratio is preferably used not only for color
development/black-and-white development but also for other subsequent
steps, such as bleach, bleach-fix, fixing, washing, and stabilization.
Desilvering is generally carried using procedures, such as bleach followed
by fixing, fixing followed by bleach-fix, bleach followed by bleach-fix,
and bleach-fix.
Bleaching agents which can be used in the bleaching or bleach-fix solution
are not particularly limited. Preferred bleaching agents include organic
complex salts of iron (III) (e.g., complex salts with aminopolycarboxylic
acids, e.g., ethylenediaminetetraacetic acid and
diethylenetriaminepentaacetic acid, aminopolyphosphonic acids,
phosphonocarboxylic acids, and organic phosphonic acids); organic acids,
e.g., citric acid, tartaric acid, and malic acid; persulfates; and
hydrogen peroxide.
Of these bleaching agents, organic complex salts of iron (III) are
particularly preferred from the standpoint of rapid processing and
prevention of environmental pollution. Examples of the aminopolycarboxylic
acids, aminopolyphosphonic acids, and organic phosphonic acids useful for
forming iron (III) complex salts include ethylenediaminetetraacetic acid,
diethylenetriaminepentaacetic acid, 1,3-diaminopropanetetraacetic acid,
propylenediaminetetraacetic acid, nitrilotriacetic acid,
cyclohexanediaminetetraacetic acid, methyliminodiacetic acid,
iminodiacetic acid, and glycol ether diaminetetraacetic acid. Sodium,
potassium, lithium or ammonium salts of these compounds are useful as
well. Of these compounds, iron (III) complex salts formed by
ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid,
cyclohexanediaminetetraacetic acid, 1,3-diaminopropanetetraacetic acid,
and methyliminodiacetic acid are preferred because of their high bleaching
ability. These ferric ion complex salts may be used in the form of a
complex salt or the complex may be formed in situ in solution by using a
ferric salt (e.g., ferric sulfate, ferric chloride, ferric nitrate,
ammonium ferric sulfate, and ferric phosphate) and a chelating agent
(e.g., aminopolycarboxylic acids, aminopolyphosphonic acids, and
phosphonocarboxylic acids). The chelating agent may be used in excess over
that necessary to form the ferric ion complex salt. Particularly preferred
iron complex salts are aminopolycarboxylic acid iron complexes, which are
used in an amount of from 0.01 to 1.0 mol/l, and preferably from 0.05 to
0.50 mol/l.
The bleaching bath, bleach-fix bath and/or a prebath thereof may contain
various bleaching accelerators. Bleaching accelerators which are
preferably used for their excellent bleaching performance include
compounds having a mercapto group or a disulfide linkage as described in
U.S. Pat. No. 3,893,858, German Patent 1,290,812, JP-A-53-95630, and
Research Disclosure, No. 17129 (Jul., 1978); thiourea compounds as
described in JP-B-45-8506, JP-A-52-20832, JP-B-53-32735, and U.S. Pat. No.
3,706,561; and halides (e.g., iodides and bromides).
The bleaching bath or bleach-fix bath may also contain a re-halogenating
agent, such as bromides (e.g., potassium bromide, sodium bromide, and
ammonium bromide), chlorides (e.g., potassium chloride, sodium chloride,
and ammonium chloride), and iodides (e.g., ammonium iodide).
If desired, the bleaching bath or bleach-fix bath may further contain one
or more inorganic or organic acids or alkali metal or ammonium salts
thereof having a pH buffer action, e.g., borax, sodium metaborate, acetic
acid, sodium acetate, sodium carbonate, potassium carbonate, phosphorous
acid, phosphoric acid, sodium phosphate, citric acid, sodium citrate, and
tartaric acid; and a corrosion inhibitor, e.g., ammonium nitrate and
guanidine.
A fixing agent used in the bleaching bath or bleach-fix bath can be
conventional water-soluble silver halide solvent, 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-dithia-1,8-octanediol; and thioureas.
These fixing agents may be used either individually or as a combination of
two or more thereof. A special bleach-fix bath containing a fixing agent
in combination with a large quantity of a halide, e.g., potassium iodide,
as described in JP-A-55-155354 can also be employed. Fixing agents which
are preferably used in the present invention are thiosulfates, and
particularly ammonium thiosulfate.
The fixing agent is used preferably in an amount of from 0.3 to 2 mol/l,
and more preferably from 0.5 to 1.0 mol/l. The fixing or bleach-fix bath
preferably has a pH of from 3 to 10, and more preferably from 5 to 9.
The bleach-fix bath may further contain various fluorescent brightening
agents, defoaming agents, surface active agents, and organic solvents,
e.g., polyvinyl pyrrolidone and methanol.
The fixing or bleach-fix bath preferably contains a sulfite ion-releasing
compound, 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), as a preservative. These
compounds are preferably present in an amount of from about 0.02 to 0.05
mol/l, and more preferably from 0.04 to 0.40 mol/l, calculated as a
sulfite ion.
While a sulfite is generally used as a preservative, other compounds, such
as ascorbic acid, carbonyl-bisulfite addition products, and carbonyl
compounds, may also be used as a preservative.
The processing time in the bleach-fix bath preferably ranges from 5 to 120
seconds, more preferably from 10 to 60 seconds. Bleach-fix processing is
carried out at a processing temperature usually ranging from 25.degree. to
60 .degree. C., and preferably from 30.degree. to 50 .degree. C. The rate
of replenishment suitably ranges from 20 to 250 ml/m.sup.2, preferably
from 30 to 100 ml/m.sup.2, of photographic material processed.
If desired, the fixing or bleach-fix bath may further contain a buffering
agent, a fluorescent brightening agent, a chelating agent, a defoaming
agent, an antifungal agent, and so on.
The silver halide color light-sensitive materials after desilvering such as
fixing or bleach-fixing are generally subjected to washing and/or
stabilization.
The amount of washing water used in the washing step can vary widely
depending on the characteristics of the light-sensitive materials (e.g.,
the kind of photographic materials such as couplers present), the end use
of the light-sensitive materials, the temperature of the washing wa | | |
