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Description  |
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FIELD OF THE INVENTION
The present invention relates to a process for developing a color photographic light-sensitive material comprising photosensitive silver halides and color couplers (e.g., color photographic papers). More particularly, the present invention
relates to a fast color development process suitable for stable processing and capable of giving images having a high color image stability.
BACKGROUND OF THE INVENTION
Processing for silver halide color photographic materials comprises three basic steps including developing (in the case of the development for color reversal materials, a black-and-white (or first) development is employed before color
development), desilvering, and washing. The desilvering step is composed of a bleach step and a fixing step or a monobath bleach-fixing ("blix") step which includes both bleaching and fixing.
In addition to the aforesaid steps, additional processing steps can be used, such as a stabilizing step, a prebath processing step before each processing step and a stop-bath processing step can be employed as is determined to be most suitable.
During color development, exposed silver halides present in imagewise exposed photographic material are reduced by a color developing agent to form silver and halide ions, and the resulting oxidized color developing agent simultaneously reacts
with color couplers to form dyes. Accordingly, when many silver halide color photographic materials are continuously processed using an automatic processor or other continuous processing equipment, halide ions accumulate in the developer, thus rendering
the developer unsuitable for further use.
Recently, in order to save natural resources and to help reduce environmental pollution, attempts have been made to reduce the amount of replenishers used with developers and other photographic processing solutions. However, an attempted
resolution to this problem, e.g., by simply reducing the amount of replenisher used in a developer, encounters problems such as reduction in the developing activity of the developer due to the accumulation of other materials that dissolve out of
photographic light-sensitive materials during processing. Such materials can include accumulated iodide and bromide ions, which are particularly strong development inhibitors, whose presence results in longer and unpredictable development times.
As another possible solution to the problem of excessive use of replenisher, there is a method of using less developer replenisher by increasing the pH and the processing temperature of the developer. However, such a method suffers from the
problem that the photographic performance is highly variable during continuous processing and, additionally, the stability of the developer is reduced.
Also, another method for decreasing development times by reducing the accumulation of iodide ions or bromide ions utilizes a silver halide photographic material having a high silver chloride content, e.g., as disclosed in JP-A-58-95345,
JP-A-59-232342 and JP-A-61-70552 (the term "JP-A" as used herein refers to a "published unexamined Japanese patent application") and WO 87-04534, and this method is considered to be an effective means of enabling fast processing with low amounts of
replenisher used with the developer.
However, the aforesaid method suffers from the problem of difficulty in attaining very fast processing times (e.g., within 30 seconds) while maintaining stable color development and ensuring stable photographic developing during continuous
processing using conventional color developing agents, such as, e.g., 4-amino-3-methyl-N-ethyl-N-.beta.-methanesulfonamidoethylaniline salt. In particular, it has been found that when silver halide photographic materials (e.g., having a high silver
chloride content) are processed at high pH or a high processing temperature, the processing speed can be increased, but the resulting stability of both the processing solution and that of the developed photographic material are so reduced as to render
this method of processing unsuitable for any practical or commercial use.
Additionally, JP-A-61-261740 and JP-A-61-275837 disclose the use of N-hydroxyalkyl-substituted p-phenylenediamine derivatives as a color developing agent, in order to inhibit undesirable variation in the photographic performance, due to the
presence of accumulated bromide ion, when silver halide photographic materials are developed that comprise silver halides having mostly silver chlorobromide. The specifications cited above describe improvement of storage stability of formed color images
by carrying out the color development in a short time in order to reduce the amount of the color developing agent remaining in the silver halide photographic materials.
Also, it is said that in the case of using a hydroxyalkyl-substituted p-phenylenediamine derivative, used as a color developing agent for developing color photographic papers, the storage stability, and in particular, the fastness to light of the
color images obtained is greatly reduced. But it has been found that when a color photographic light-sensitive material (paper) having a silver halide emulsion layers containing at least 80 mol % silver chloride is processed by a color developer
containing a 4-amino-3-methyl-N-ethyl-N-.beta.-hydroxyethylaniline salt, which is used as a color developing agent for conventional color photographic negative films and not containing benzyl alcohol, color images are formed fast (within 30 seconds) and
the processing stability is excellent.
However, this method suffers from the problem that the fastness of the color images is greatly inferior to the case of using a 4-amino-3-methyl-N-ethyl-N-.beta.-methanesulfonamidoethylaniline salt in spite of processing in a short period of time. British Patent 807,899 discloses that the use of certain N-hydroxyalkyl substituted p-phenylenediamine derivatives provides excellent storage stability of cyan color images. However, with a conventional processing time containing a long color developing
time, the storage stability of yellow color images and magenta color images are poor and the stored images greatly deteriorated the color balance and could not be worthy of appreciation.
The storage stability of color images is generally an important factor for print materials such as color paper, and hence 4-amino-3-methyl-N-ethyl-N-.beta.-methanesulfonamidoethylaniline salts have been used as the best compound.
At present, it has been a long-standing problem in this art to provide a commercially or practically suitable process that can reduce the amount of replenishers needed and, at the same time, reduce the processing and/or development time.
However, as described above, previous attempts to provide such a process have failed, due to the occurrence of undesirable additional problems, including, e.g., reduced storage stability and reduced light fastness of color images formed on a developed
photographic material.
For example, since the color images of developed photographic materials formed, using the aforesaid 4-amino-3-methyl-N-ethyl-N-.beta.-hydroxyethylaniline salt (which is a color developing agent for developing color photographic negative films),
at present are greatly reduced, the aforesaid color developing agent is practically unsuitable for developing color photographic papers.
In general, the rate of color development varies according to which type p-phenylenediamine derivative is used as a component of the developing agent. For example, a color developing agent having a hydrophobic group at the N-substituted
position, such as a 4-amino-3-methyl-N,N-diethylaniline salt and a 4-amino-3-methyl-N-ethyl-N-methoxyethylaniline salt, is readily distributed with a coupler or other developer components into an oil drop phase of a photographic material, in order to
increase the rate of developing reactions. Thus, such a color developing agent has been used for faster development. Examples of such developing agents and how they are made are disclosed in U.S. Pat. Nos. 3,656,905, 3,656,925 and 4,035,188.
Alternatively, a fast method of color development has been employed using a color developing agent having a hydrophilic group at the N-substituted position, such as a 4-amino-3-methyl-N-ethyl-N-.beta.-methanesulfonamidoethylaniline salt and a
4-amino-3-methyl-N-ethyl-N-.beta.-hydroxyethylaniline salt. Such a developer additionally contains benzyl alcohol, in order to accelerate the distribution of the color developing agent in the oil drop phases of a color photographic light-sensitive
material.
However, such a method (using a hydrophobic group-containing agent, as described above) has the problem that when a color photographic material is color developed for a period of time of about 30 seconds or less, an insufficient contact of the
developing agent with the lower emulsion layers of the color photographic material is effected, thereby producing developed color images having inferior color balance. Additionally, the presence of benzyl alcohol in the color developer may increase the
coloring density in the uppermost emulsion layer but have little or no effect on the coloring density of the lowermost emulsion layer, thereby additionally causing poor or nonuniform color images on the developed photographic material and, hence, the
addition of benzyl alcohol is not desired.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a method for continuous processing of color photographic light-sensitive material which provides a developed photographic material having extended color fastness or stability,
suitable for long storage, and additionally provides for fast development using relatively short periods of time in a developer.
Another object of the present invention is to provide a method for processing a color photographic light-sensitive material, characterized by producing reduced or no color developer waste while, at the same time, allowing for the use of
relatively short development times.
In accomplishing the foregoing objects, there has been provided a method for developing an imagewise exposed silver halide color photographic material which comprises developing a color photographic material containing silver halide grains
comprising (i) substantially no silver iodide and (ii) at least about 80 mol % silver chloride with a developer comprising (i) substantially no benzyl alcohol and (ii) a p-phenylenediamine derivative represented by the formula (I): ##STR2## wherein
R.sup.1 and R.sup.2 each represents an alkyl group having from 1 to 4 carbon atoms and R.sup.2 represents a straight chain or branched alkylene group having 3 or 4 carbon atoms; for 30 seconds or less, preferably 20 seconds or less, and preferably at a
temperature of at least 30.degree. C.
Another embodiment of the present invention provides an amount of replenisher for a color developer that is not more than about 120 ml, and preferably from about 15 to 60 ml per square meter of the color photographic material.
According to another embodiment of the present invention, the above described developing process is carried out without using replenishers (however, water lost by evaporation can be replenished according to the present invention).
Developing time, in this context, refers to a period of time during which the color photographic material retains in contact with the bulk of a color developer.
DETAILED DESCRIPTION OF THE INVENTION
As the result of various investigations on a very fast development process of color photographic light-sensitive papers containing silver halide of a high silver chloride content using a p-phenylenediamine derivative as the color developing
agent, it has now been found that the color developer containing the color developing agent being used in the present invention, which will be described below, enables good stable processing and fast processing in a low replenishing system and at the
same time can provide color images having an excellent light fastness.
From the aforesaid matters, it has been concluded that the following two factors are important for attaining very fast processing of not longer than 30 seconds with less deviation of the photographic performance in continuous processing.
That is, the first factor is that a color developing agent is rapidly supplied to the lowermost emulsion layer of a color photographic material. That is, a color developing agent which is reluctant to be trapped in oil drop phases and which has
a high diffusion rate is used. A developing agent having a hydrophilic group is preferably used. Also, it is preferred that benzyl alcohol accelerating the distribution of a color developing agent into oil drop phases is not used.
A second factor is that a color developing agent having a hydrophilic group and a high reducing power is used in order to enhance developability. Thus, the development activity of, for example, a
4-amino-3-methyl-N-ethyl-N-.beta.-methanesulfonamidoethylaniline salt, which is used for processing color photographic papers at present, can be increased to be used in the method of the present invention by replacing the N-methanesulfonamido group of
the salt with an N-hydroxyalkyl group. Such a replacement increases hydrophilic properties as a developer and, at the same time, increases its reducing power. But, the reduction of the light fastness of color images formed is unavoidable, as described
above.
However, it has been discovered that by only replacing the hydroxyethyl group of the 4-amino-3-methyl-N-ethyl-N-.beta.-hydroxyethylaniline salt with a hydroxypropyl group or a hydroxybutyl group, the fastness of the color images formed to light
is, contrary to the expectation of the skilled artisan, greatly improved. It is an astonishing fact that a compound according to formula (I), as shown herein, wherein R.sup.2 of the hydroxyalkyl group (R.sup.2 OH) is replaced with a straight chain or
branched alkylene group having 3 or 4 carbon atoms, can provide color images having excellent long storage stability as described above.
Also, contrary to a compound according to formula (I), used in the method of the present invention, a compound having a straight chain or branched alkylene group having 5 or more carbon atoms as R.sup.2 is inferior in the light fastness of
colored images and greatly inferior in fast processing, to such a compound, used in the method of the present invention,.having a straight chain or branched alkylene group having 3 or 4 carbon atoms as R.sup.2.
Thus, it has been found that a compound according to formula (I), wherein R.sup.2 in the hydroxyalkyl group is a straight or branched group having 3 to 4 carbon atoms, and, in particular, 4 carbon atoms, is best in both light fastness of colored
images formed and having the property of very fast processing times.
It has been found that particularly when the color development is carried out for a period of time as short as 30 seconds or less, the light fastness of all yellow, magenta and cyan color images is greatly improved and the stored images have an
excellent color balance.
With respect to the magenta color images it has also been found that in the fast color development process of the present invention the storage stability of the color images are more greatly improved and the stain formation caused by storage can
be more significantly inhibited with 2-equivalent couplers having an anion-releasing group introduced at a coupling position than with the conventional 5-pyrazolone based 4-equivalent couplers. It has also been found that preferably a pyrazoloazole
based magenta coupler, particularly preferably a magenta coupler represented by formula (M-II) described hereinbelow can be used to obtain an image having a still further improved long term storage stability in a very fast development process.
As described above, it has been an unexpected fact that the combined use of the above mentioned color developing agent characterizing the present invention and a specific magenta coupler can provide a color image in a very fast development
process which has a good long term storage stability and which is superior to images obtained by a conventional color developing agent.
Knowledge of the aforesaid color developing agent has not hitherto been known and it is considered to be a unique phenomenon for the color images obtained by very fast processing a color photographic material using a color developer comprising
substantially no benzyl alcohol.
Practical aspects of the present invention are described in greater detail below.
A color developing agent used in the method of the present invention is represented by the following formula (I), as described above, as follows: ##STR3## wherein R.sup.1 and R.sup.2 each represents an alkyl group having from 1 to 4 carbon atoms
and R.sup.2 represents a straight chain or branched alkylene group having 3 or 4 carbon atoms.
Specific examples of the alkyl group shown by R.sup.1 and R.sup.2 include methyl, ethyl, propyl, isopropyl, butyl, and sec-butyl. Also, specific examples of the alkylene group shown by R.sup.2 include propylene, butylene, 1-methylethylene,
2-methylethylene, 1-methylpropylene, 2-methylpropylene, and 3-methylpropylene.
In formula (I), R.sup.1 represents preferably ethyl or propyl; R.sup.3 represents preferably methyl or ethyl; and R.sup.2 represents preferably propylene or butylene as a main chain, and most preferably butylene.
A compound shown by formula (I) is very unstable in the case of storing the compound as a free amine and hence it is preferred that such a compound be generally stored as a salt of an inorganic acid or an organic acid and is used as a free amine,
e.g., by adding such a compound to a color developer.
Examples of an inorganic acid and organic acid forming a salt of a compound of formula (I) include hydrochloric acid, sulfuric acid, phosphoric acid, p-toluenesulfonic acid, methanesulfonic acid, and naphthalene-1,5-disulfonic acid.
Specific examples of compounds shown by formula (I), which can be used as the color developing agent in the method of the present invention are illustrated below, but the present invention is not limited to these compounds. ##STR4##
The amount (concentration) of the color developing agent being used in the method of the present invention is preferably in the range from about 0.2 to 60 g, and more preferably from about 1 to 30 g, per liter of color developer.
A processing temperature for a color developer is preferably in a range of about 30.degree. to 50.degree. C., in order to achieve development in a short period of time. Also, if the developing temperature is over about 50.degree. C., Dmin
(the minimum density) of color images formed is increased and hence the processing temperature is preferably lower than about 50.degree. C.
Color developing agents, used in the method of the present invention, can be synthesized according to methods similar to those described in, e.g., the Journal of American Chemical Society, Vol. 73, 3100 (1951).
Color developing agents used in the method of the present invention can be used alone or together with another known p-phenylenediamine derivative. Specific examples of the compounds which can be used together with the color developing agent
according to the method of the present invention are illustrated below, but the present invention is not limited to these compounds.
D-1: N,N-Diethyl-p-phenylenediamine
D-2: 2-Amino-5-diethylaminotriene
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.-butoxyethylaniline
Of the aforesaid p-phenylenediamine derivatives, 4-amino-3-methyl-N-ethyl-N-[.beta.-(methanesulfonamido)ethyl]aniline (Compound D-6) is particularly preferred.
Also, these p-phenylenediamine derivatives can be used in the form of salts, such as, e.g., sulfates, hydrochlorides, sulfites, p-toluenesulfonates, nitrates, and naphthalene-1,5-disulfonates.
An amount of aromatic primary amine developing agents can be from about 0.1 g to about 20 g per liter of color developer. Preferably, a p-phenylenediamine derivative used together can be used in an amount of from 1/10 mol to 10 mols per mol of a
color developing agent according to formula (I), for use in the method of the present invention.
In accordance with a use of the present invention, color developer comprises substantially no benzyl alcohol. In the present invention, the term "comprising substantially no benzyl alcohol" means that a color developer can comprise less than
about 2 ml/liter, more preferably less than about 0.5 ml/liter benzyl alcohol, and most preferably a color developer with no benzyl alcohol.
It is preferred that a color developer for use in the present invention also does not substantially comprise sulfite ion. Sulfite ion has a function as a preservative for a color developing agent, and at the same time, functions to dissolve
silver halides and also to reduce dye-forming efficiency by reacting with an oxidized product of a color developing agent. Such a function is considered to be one of the causes of increased variation in the photographic developing characteristics,
associated with continuous processing. The term "does not substantially comprise sulfite ion" means that a concentration of sulfite ion in a color developer, used in the present invention, is preferably less than about 3.0.times.10.sup.-3 mol/liter, and
most preferably a color developer of the present invention comprises no sulfite ion. However, a small amount of sulfite ion, used for preventing oxidation of a developer kit, which is comprised of a concentrated color developer, diluted at use, is
outside the aforesaid definition in the present invention.
It is preferred that a color developer for use in the present invention does not substantially contain sulfite ion, as described above, and it is more preferred that the color developer does not substantially contain hydroxylamine. This is
because hydroxylamine, used as a preservative for color developers and, at the same time, has a silver development activity by itself, thereby, it is considered that the deviation of the concentration of hydroxylamine in the developer gives adverse
effects on the photographic characteristics of color images formed. The term "does not substantially comprise hydroxylamine" means that the concentration of hydroxylamine in the color developer is preferably less than about 5.0.times.10.sup.-3
mol/liter, and the color developer comprises most preferably no hydroxylamine.
A color developer for use in the present invention contains more preferably an organic preservative in place of the aforesaid hydroxylamine and sulfite ion.
In this case, the term "organic preservative" means all organic compounds capable of reducing the rate of deterioration of an aromatic primary amine color developing agent, by adding a color developer for color photographic light-sensitive
materials, such as organic compounds having a function of preventing a color developing agent from being oxidized by air, or other compounds.
Examples of particularly effective organic preservatives include hydroxylamine derivatives (excluding hydroxylamine, the same applies hereinafter), hydroxamic acids, hydrazines, hydrazides, phenols, .alpha.-hydroxyketones, .alpha.-aminoketones,
saccharides, monoamines, diamines, polyamines, quaternary ammonium salts, nitroxy radicals, alcohols, oximes, diamide compounds, and condensed ring type amines. Examples of these compounds are disclosed in JP-A-63-4235, JP-A-63-5341, JP-A-63-30845,
JP-A-63-21647, JP-A-63-44655, JP-A-63-46454, 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-63-44646, and JP-A-52-143020, U.S. Pat. Nos. 3,615,503 and 2,494,903, JP-B-48-30496 (the term
"JP-B" as used herein refers to an "examined Japanese patent publication"), and Japanese Patent Applications 185578/89, 198676/89, and 199646/89.
A color developer for use in the present invention can further contain other preservatives, such as, e.g., various kinds of metals, described in JP-A-57-44148 and JP-A-57-53749; salicylic acids, described in JP-A-59-180588; alkanolamines,
described in JP-A-54-3532; polyethyleneimines, described in JP-A-56-94349; and aromatic polyhydroxy compounds described in U.S. Pat. 3,746,544. In the aforesaid preservatives, alkanolamines such as triethanolamine, etc., dialkylhydroxylamines such as
diethylhydroxylamine, etc., hydrazine derivatives and aromatic polyhydroxy compounds are particularly preferred.
Of the aforesaid organic preservatives, hydroxylamine derivatives and hydrazine derivatives (hydrazines and hydrazides) are most preferred and details thereof are described, e.g., in JP-A-1-97953, JP-A-1-186939, JP-A-1-186940, and JP-A-1-187557.
In this case, it is more preferred to use the aforesaid hydroxylamine derivatives or hydrazine derivatives and the aforesaid amines together in order to improve the stability of the color developer and also to further improve the stability
thereof during continuous processing.
Such amines include, e.g., cyclic amines, described in JP-A-63-239447; amines, described in JP-A-63-128340, and other amines, described in JP-A-1-186939 and JP-A-1-187557.
In the method of the present invention, it is preferred that a color developer comprise chloride ion in an amount in the range of from about 3.5.times.10.sup.-3 to 3.0.times.10.sup.-1 mol/liter, and more particularly from about 1.times.10.sup.-2
to 2.0.times.10.sup.-1 mol/liter.
If the content of chloride ion is more than about 3.0.times.10.sup.-1 1 mol/liter, the development is delayed and hence such a chloride content is undesirable for attaining an object of the present invention of giving high maximum density by fast
processing. Also, if the chloride content is less than about 3.5.times.10.sup.-3, the formation of fog is increased in the developed material.
In the method of the present invention, a color developer can be used that also comprises bromide ion in an amount of preferably from about 0.5.times.10.sup.-5 to 1.0.times.10.sup.-3 mol/liter, and more preferably from about 3.0.times.10.sup.-5
to 5.times.10.sup.-4 mol/liter.
If the bromide ion concentration is more than about 1.times.10.sup.-3 mol/liter, the development is delayed and the maximum density and sensitivity are lowered, while if the bromide content is less than about 0.5.times.10.sup.-5 mol/liter, the
formation of fog cannot be sufficiently prevented.
In the method of the present invention, chloride ion and bromide ion can be directly added to a color developer or can be dissolved in a developer from color photographic light-sensitive materials during processing.
In the case of directly adding chloride ion to the color developer, as a chloride ion supplying material, sodium chloride, potassium chloride, ammonium chloride, lithium chloride, nickel chloride, magnesium chloride, manganese chloride, calcium
chloride, and cadmium chloride can be used and sodium chloride and potassium chloride are preferred.
Also, chloride ion can be supplied into a color developer from an optical whitening agent contained in a color developer.
In the case of directly adding bromide ion, as a bromide ion supplying material, sodium bromide, potassium bromide, ammonium bromide, lithium bromide, calcium bromide, magnesium bromide, manganese bromide, cerium bromide, and thallium bromide can
be used and potassium bromide and sodium bromide are preferred.
When chloride ion and bromide ion are dissolved into a developer from color photographic light-sensitive materials, the chloride ion and the bromide ion can be supplied from silver halide emulsion layers thereof or from other layers than the
emulsion layers.
The pH of a color developer for use in the present invention is preferably from about 9 to 12, and more preferably from about 9 to 11.0.
A color developer may further contain other components.
For example, for maintaining the aforesaid pH, it is preferred to use various kinds of buffers. Such buffers include, e.g., carbonates, phosphates, borates, tetraborates, hydroxybenzoates, glycyl salts, N,N-dimethylglycine salts, leucine salts,
norleucine salts, guanine salts, 3,4-dihydroxyphenylaranine salts, aranine salts, aminobutyrates, 2-amino-2-methyl-1,3-propanediol salts, valine salts, proline salts, trihydroxyaminomethane salts, lysine salts. Carbonates, phosphates, tetraborates, and
hydroxybenzoates are particularly preferred since they are excellent in solubility and buffer capacity in a high pH range of at least 9.0 and have the advantages that they do not give adverse effects (e.g., fogging) to the developed photographic material
when they are added to a color developer. These buffers are also inexpensive.
Suitable examples of these buffers that can be used in the method of the present invention include sodium carbonate, potassium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, sodium tertiary phosphate, potassium tertiary
phosphate, sodium dihydrogenphosphate, potassium dihydrogenphosphate, 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 method of the present invention is not limited to these compounds.
The amount of the buffer being added to a color developer is preferably at least about 0.1 mol/liter, and a range from about 0.1 to 0.4 mol/liter is particularly preferred.
Furthermore, a color developer may contain various kinds of chelating agents for preventing the precipitation of calcium and magnesium in a color developer or for improving the stability of a color developer used in the present invention.
Examples of suitable chelating agents are nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, N,N,N-trimethylenephosphonic acid, ethylenediamine-N,N,N',N'-tetramethylenesulfonic acid,
transcyclohexanediaminetetraacetic 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.
If necessary, these chelating agents can be used in combination.
The amount of the chelating agent can be sufficient for blocking metal ions in a color developer and can be present, for example, in concentrations from about 0.1 to 10 g per liter of color developer.
A color developer may further comprise a development accelerator.
As the development accelerator being used in the present invention, examples include thioether series compounds, e.g., as described in JP-B-37-16088, JP-B-37-5987, JP-B-38-7826, JP-B-44-12380 and JP-B-45-9019, and U.S. Pat. No. 3,813,247;
p-phenylenediamine series compounds described in JP-A-52-49829 and JP-A-50-15554; quaternary ammonium salts described in JP-A-50-137726, JP-B-44-30074, JP-A-56-156826 and JP-A-52-43429; amine series compounds described in U.S. Pat. Nos. 2,494,903,
3,128,182, 4,230,796, 2,482,546, 2,596,926 and 3,582,346 and JP-B-41-11431; polyalkylene oxides described in JP-B-37-16088, JP-B-42-25201, JP-B-41-11431 and JP-B-42-23883, U.S. Pat. Nos. 3,128,183 and 3,532,501; 1-phenyl-3pyrazolidones, and
imidazoles.
In the present invention, a color developer can also comprise an optional antifoggant.
As the antifoggant, suitable examples are alkali metal halides such as sodium chloride, potassium bromide, potassium iodide, and organic antifoggants. Typical examples of organic antifoggants are nitrogen-containing heterocyclic compounds such
as benzotriazole, 6-nitrobenzimidazole, 5-nitroisoindazole, 5-methylbenzotriazole, 5-nitrobenzotriazole, 5-chlorobenzotriazole, 2-thiazolebenzimidazole, 2-thiazolylmethylbenzimidazole, indazole, hydroxyazaindolizine, adenine, etc.
It is preferred that a color developer for use in the present invention can comprise an optical whitening agent, such as, preferably, 4,4'-diamino-2,2'disulfostilbene series compounds. The amount of the optical whitening agent that can be used
in the present invention is from about 0 to 5 g/liter, and preferably from about 0.1 to 4 g/liter.
Also, a color developer can further comprise various kinds of surface active agents, such as alkylsulfonic acids, arylsulfonic acids, aliphatic carboxylic acids, and aromatic carboxylic acids.
In the case of reducing the amount of replenishers used, it is preferred to reduce the contact area of a processing solution with air, in order to prevent the occurrence of evaporation and oxidation of a processing solution.
The contact area of a photographic processing solution in a processing tank and air can be shown by the ratio defined below.
(A): Contact area (cm.sup.-2) of a processing solution and air
(B): Volume (cm.sup.3) of the processing solution
The aforesaid open ratio is preferably not higher than about 0.1 and preferably from about 0.001 to 0.05.
As a method for reducing the open ratio, e.g., placing a cover such as a float lid or other cover on the surface of a processing solution in a processing tank can be used, or, alternatively, using a movable lid, such as is described in
JP-A-62-241342, or a slit processing process described in JP-A-63-216050.
It is preferred that a means for reducing the open ratio is applied to not only a color developer and a black-and-white developer but also to other various subsequent processing steps, such as bleaching, fixing (or bleach-fixing), washing,
stabilizing.
A desilvering step which can be applied to the process of the present invention is further described below.
A desilvering step is generally composed of a bleaching step and fixing step; a fixing step and a bleach-fixing (blixing) step; a bleaching step and a blixing step; or a blixing step.
Then, a bleaching solution, a blixing solution, and a fixing solution, which can be applied to the present invention, are further described below.
As a bleaching agent which is used for a bleaching solution or a blixing solution, any bleaching agents can be used but, in particular, organic complex salts (e.g., complex salts of aminopolycarboxylic acids such as ethylenediaminetetraacetic
acid, diethylenetriaminepentaacetic acid, or organic phosphonic acids, such as aminopolyphosphonic acid, phosphonocarboxylic acid) of iron(III); organic acids such as citric acid, tartaric acid, malic acid, etc.; persulfates; and hydrogen peroxide are
preferred.
In these bleaching agents, organic complex salts of iron(III) are particularly preferred for fast processing and for the prevention of environmental pollution.
Examples of the aminopolycarboxylic acid, aminopolyphosphonic acid, organic phosphonic acid, or the salts thereof useful for forming the organic complex salts of iron(III) are ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid,
propylenediaminetetraacetic acid, nitrilotriacetic acid, cyclohexanediaminetetraacetic acid, methyliminodiacetic acid, iminodiacetic acid, and glycol ether diaminetetraacetic acid. These compounds can be in the form of sodium salts, potassium salts,
lithium salts or ammonium salts.
In these compounds, iron(III) complex salts of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, cyclohexanediaminetetraacetic acid, 1,3-diaminopropanetetraacetic acid, and methyliminodiacetic acid are preferred because of
their high bleaching strength.
These complex salts of ferric ion can be used in the form of a complex salt or a complex salt of ferric ion can be formed in a solution by using a ferric salt (such as ferric sulfate, ferric chloride, ferric nitrate, ferric ammonium sulfate, or
ferric phosphate), and a chelating agent (such as aminopolycarboxylic acid, aminopolyphosphoric acid, or phosphonocarboxylic acid).
Of the ferric complex salts, a ferric salt of an aminopolycarboxylic acid is preferred and the amount thereof is from about 0.01 to 1.0 mol/liter, and preferably from about 0.05 to 0.50 mol/liter.
For a bleaching solution, a blixing solution and/or a prebath therefor various compounds can be used as a bleach accelerator.
Examples of bleach accelerator are compounds having a mercapto group or a disulfide bond 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); thiourea series
compounds described in JP-B-45-8506, JP-A-52-20832 and JP-A-53-32735, and U.S. Pat. No. 3,706,561; halides such as iodides, bromides, etc. They are preferred due to their excellent bleaching strength.
Moreover, a bleaching solution or a blixing solution which can be applied in the present invention can further comprise a rehalogenating agent such as a bromide (e.g., potassium bromide, sodium bromide, and ammonium bromide), a chloride (e.g.,
potassium chloride, sodium chloride, and ammonium chloride), and an iodide (e.g., ammonium iodide).
Also, a bleaching solution or a blixing solution can comprise a corrosion inhibitor such as an inorganic acid or organic acid having a pH buffer capacity and the alkali metal or ammonium salts thereof (e.g., borax, sodium metaborate, acetic acid,
sodium acetate, sodium carbonate, potassium carbonate, phosphorous acid, phosphoric acid, sodium phosphate, citric acid, sodium citrate, tartaric acid, and ammonium nitrate), and guanidine.
As the fixing agent which is used for a blixing solution or a fixing solution, 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 water-soluble silver halide solvents such as thioureas can be used. They can be used alone or as a mixture.
Also, a specific blixing solution comprising a fixing agent and a large amount of a halide such as potassium iodide, e.g., as described in JP-A-55-155354 can be used in the present invention. In the present invention, the use of thiosulfates, in
particular, ammonium thiosulfate, as a fixing agent is preferred.
The amount of a fixing agent is preferably from about 0.3 to 2 mols, and more preferably from about 0.5 to 1.0 mol per liter of a blixing solution or a fixing solution. The pH range of a blixing solution or a fixing solution is preferably from
about 3 to 10, and particularly preferably from about 5 to 9.
Also, a blixing solution can further contain an optical whitening agent, a defoaming agent, a surface active agent, or an organic solvent, such as polyvinylpyrrolidone, methanol.
Furthermore, a blixing solution or a fixing solution preferably contains a preservative and as a preservative, sulfite ion-releasing compounds such as sulfites (e.g., sodium sulfite, potassium sulfite, and ammonium sulfite), bisulfites (e.g.,
ammonium bisulfite, sodium bisulfite, and potassium bisulfite), metabisulfites (e.g., potassium metabisulfite, sodium metabisulfite, and ammonium metabisulfite) can be used.
Such a preservative is contained in the processing solution in an amount of from about 0.02 to 0.05 mol/liter, and more preferably from about 0.04 to 0.40 mol/liter calculated as sulfite ion.
As the preservative, sulfites are generally used but ascorbic acid, a carbonyl-bisulfite addition product, or a carbonyl compound can be also added.
Furthermore, a blixing solution or a fixing solution can further comprise a buffer, an optical whitening agent, a chelating agent, a defoaming agent or an antifungal agent.
After a desilvering process, such as fixing or blixing, a washing step and/or a stabilizing step is generally applied.
The amount of washing water in a washing step can be selected from a wide range of conditions according to the characteristics of the previous step (e.g., materials such as couplers used) and ultimate use of a color photographic light-sensitive
materials being processed, the temperature of a washing water, the number (stage number) of washing tanks, the replenishing system (countercurrent system or normal current system), and other various circumstances.
Of the aforesaid factors, the relation of a washing tanks and the amount of washing water in a multistage countercurrent system can be determined by a method, such as is described in Journal of the Society of Motion Picture and Television
Engineers, Vol. 64, 248-253 (May, 1955). The stage number in a multistage countercurrent system used in the method of the present invention is preferably from about 2 to 6, and more preferably from about 2 to 4.
When a multistage countercurrent system is used in the present invention, the amount of washing water can be greatly reduced to, for example, from about 0.5 to 1 liter per square meter of the color photographic material (photographic paper) with
a beneficial effect of the present invention. However, in the case of reducing the amount of washing water, there occurs a problem that by increasing the residence time in the tanks, bacteria increase and suspended matters thus formed attach to the
color photographic materials being processed.
For solving the aforesaid problem, a method of reducing calcium and magnesium, e.g., as described in JP-A-62-288838, can be very effectively used. Also, chlorine series antibacterial agents, such as isothiazolone compounds and thiabendazoles
described, e.g., in JP-A-57-8542 and chlorinated sodium isocyanurate described, e.g., in JP-A-61-120145; benzotriazole described, e.g., in JP-A-61-267761; copper ions; and antibacterial agents described, e.g., in Hiroshi Horiguchi, Bohkin Bohbai no
Kagaku (Antibacterial and Antifungal Chemistry), published by Sankyo Shuppan K.K. 1986, Biseibutsu no Mekkin, Sakkin, Bohbai Gijutsu (Germicidal and Antifungal Techniques of Microorganisms), edited by Eisei Gijutsukai, published by Kogyo Gijutsukai,
1982, and Bohkin Bohbai Zai Jiten (Antibacterial and Antifungal Agents Handbook), edited by Nippon Bohkin Bohbai Gakkai, can be used.
Furthermore, a surface active agent, for use as a wetting agent, and a chelating agent such as ethylenediaminetetraacetic acid (EDTA), for use as a water softener can be used in the washing water in the method of the present invention.
Subsequent to the aforesaid washing step, or without employing a washing step, color photographic materials can be processed by the use of a stabilizing solution. A stabilizing solution comprises a compound having an image stabilizing function
and examples of such a compound are aldehyde compounds such as formalin, etc., buffers for controlling suitable pH of layers for the stabilization of dyes, and ammonium compounds. Also, a stabilizing solution can further comprise the aforesaid various
kinds of antibacterial agents and antifungal agents for inhibiting the growth of bacteria in the solution and for imparting an antifungal property to the thus-developed color photographic material.
Furthermore, a stabilizing solution can also contain a surface active agent, an optical whitening agent, or a hardening agent.
When processing color photographic light-sensitive materials according to the process of the present invention, a color photographic material can be directly processed by a stabilizing step without employing a washing step, e.g., according to
methods described in JP-A-57-8543, JP-A-58-14834, and JP-A-60-220345.
Furthermore, in a preferred embodiment, a stabilizing solution comprises a chelating agent such as 1-hydroxyethylidene-1,1-diphosphonic acid, and ethylenediaminetetramethylenephosphonic acid, or a magnesium or bismuth compound.
When a washing solution or a stabilizing solution is used after a desilvering process, a so-called rinse solution can be used.
The pH of washing water and stabilizing solution is preferably from about 4 to 10, and more preferably from about 5 to 8. The temperature for a washing step or a stabilizing step is variously selected according to the use and the characteristics
of the color photographic light-sensitive material being processed, but is generally from about 15.degree. C. to about 45.degree. C., and preferably from about 20.degree. C. to about 40.degree. C. Processing time can be variably selected but a
shorter time is preferred from the viewpoint of fast processing. Processing time is preferably from about 15 seconds to about 1 minute and 45 seconds, and preferably from about 30 seconds to about 90 seconds.
It is preferred that the amount of replenisher used for a processing solution be reduced in order to lower operating cost, the amount of waste solution, and the amount of processing of waste solution.
The amount of replenisher used can be from about 0.5 to 50 times, and preferably from about 3 to 40 times, the amount carried by a unit area of a color photographic material from a prebath. Also, the amount thereof can be less than 1 liter,
preferably less than about 500 ml per square meter of color photographic material.
Also, a replenisher can be replenished continuously or intermittently.
Liquid used for a washing step and/or a stabilizing step can be reused for a previous step. As an example thereof, the amount of washing water is reduced by employing a multistage countercurrent system, an overflow liquid of washing water is
supplied to a blixing bath which is a prebath therefor, and a concentrated liquid is replenished to the blixing bath, whereby the amount of the waste solution is reduced.
After a washing and/or stabilizing step, as described above, a color photographic material thus processed can be dried for about 10 seconds to about 10 minutes, at a temperature of from about 90.degree. C. to about room temperature. In
addition, a drying step may be omitted as is most suitable.
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