MXPA99007381A - Concentrate developer of homogeneo photographic color of a single part and my manufacturing method - Google Patents

Abstract

A single-part aqueous homogeneous color developer concentrate comprising a color developer in the form of a free base, an antioxidant for the color developing agent, a pH regulating agent and a straight-chain organic solvent is disclosed. substituted by hydroxyl, water-miscible or water-soluble, present in a concentration, such that the weight ratio of water to the organic solvent is from 15:85 to 50:50. This composition is prepared in a unique manner, that is, by combining the indicated components and by removing the sulfate anions commonly present in the color developing agents by precipitation with alkali metal ions before the addition of additional components. The concentrate can be used to make a concentrated working processing solution or it can be used as a filler composition with appropriate dilution

Description

CONCENTRATE DEVELOPER OF HOMOGENEOUS PHOTOGRAPHIC COLOR OF A SINGLE PART AND METHOD OF MANUFACTURE OF THE SAME DESCRIPTION OF THE INVENTION The present invention is concerned with homogeneous photographic color developer concentrates of a single part and with a method for their manufacture. These concentrates and methods are useful in the field of photography to provide color photographic images. The basic processes for obtaining useful color images from exposed color silver halide photographic materials include various stages of photochemical processing such as color development or development, silver bleaching, silver halide fixation and water washing or stabilization. of dye image when using appropriate photochemical compositions. Color developing photographic compositions are used to process color photographic materials such as films and color photo papers to provide the desired dye images prematurely in the photoprocessing method. Such compositions generally contain color developer agents, for example 4-amino-3-methyl-N- (2-methanesulfonamidoethyl) aniline as reducing agents to react with appropriate color-forming couplers to form the desired dyes. U.S. Patent 4,892,804 discloses conventional color developer compositions that have found considerable commercial success in the photographic industry. Other known color developer compositions are disclosed in U.S. Patents 4,876,174, 5,354,646 and 5,660,974. It is common practice to add a "filler" solution to the color developer composition in the processing machine in order to replace the photochemical compounds that are depleted during the reaction or transported by the processed materials. Such filler ensures uniform development and maximum stability of the color developer. The color developer compositions are commonly provided in three or more "parts" (or solutions) that are mixed immediately before use. Frequently multiple parts are required in order to separate and preserve the chemical activity and solubility of the components that may otherwise deteriorate or may react with each other when stored together for long periods of time under alkaline conditions. For example, a part could include a color developer agent. Another part could contain agents to preserve the alkalinity of the mixed color developer composition. Still another part may include an optical brightener. After the combination of all the parts and water, a homogeneous color developer composition for the working concentrate solution in the processing machine can usually be obtained. There is a desire in the industry to reduce the number of parts used to prepare color developer compositions and in particular to prepare filling solutions. A wide range of compositions are described in the art or commercially available as ready-to-use solutions, concentrates or dry formulations. The liquid concentrates have only to be diluted with water to provide a concentrated working solution. Dry formulations only need to be dissolved in water. For example, EP-A-0 793,141 discloses a two-part color developer composition that can be supplied in either solid or liquid form. It is generally known that the concentrations of various photochemical compounds used in a photographic processing bath must fall within certain narrow limits in order to provide optimum performance. The most important solvent for such photoprocessing is water. Most inorganic salts can easily be dissolved in water whereas organic photochemical compounds in such process baths usually have an appropriate solubility in water at the desired operating concentrations. Nevertheless, water is an asset and a major problem of photographic compositions ready to be used and some concentrated photographic compositions due to their presence in great quantity. As a result, the costs of manufacturing, transporting and storing such compositions grows rapidly. Typically, the user of the photochemical compositions has available water in which the individual photochemical compounds could be mixed or diluted, but this is usually not practical for a variety of reasons. The exact composition of photochemical compounds is not easily determined by a common user and it is not likely that manufacturers will easily provide their formulations for that purpose. Furthermore, even if the formulations are known, mixing errors can give poor processing results. For these reasons, there is a tendency in the photographic industry to provide photoprocessing compositions (in which color developer compositions are included), in concentrated form, such that the manufacturer and user do not need to pay for the use, transportation or storage of large volumes of water and to allow the use of smaller containers. In addition, there has been a desire in the industry to provide compositions that can be used outside of containers without the need for mixing of several components (to thereby reduce mixing errors), such as in what is known as "stuffing" processors. automatic".

The industry has investigated the use of concentrates and solid mixtures (in which powders and tablets are included). In most cases, concentrates are convenient to use, but can have high packing costs compared to powders. The powders allow a high concentration, but not every photochemical composition can be dried in a stable powder. In addition, the powders present problems with the formation of fumes or fine powders, needs for separate packages and more troublesome dosing or mixing procedures. Not all dry formulations are easily dissolved in water. Another concentrated form known in the art is a chemical pulp or suspension, as described for example in EP-A-0 204,372 and EP-A-0 800,111. These formulations still have other deviations, i.e., lack of homogeneity and slow dissolution rate of the solid components. The casual observer could consider that all conventional "parts" used to provide the color developer compositions could easily be combined to form a single part homogeneous composition. This is not as easy as you can think. The interactions between and the deterioration of the photochemical compounds are amplified in concentrated form and the resulting action on the processed photographic materials may be undesirable due to the resulting poor images. Some color developer compositions are commercially available in a one part formulation that overcomes some of the indicated problems, but due to the presence of precipitates (such as in suspensions) or multiple solvent phases, they require vigorous stirring or mixing before of use. Such compositions are limited generally to small volumes. In addition, the presence of precipitates or "mud" may not be attractive to users. Some users may not have appropriate equipment for proper agitation of the multi-stage compositions. Additional small volume easy-to-use color developer compositions are described in U.S. Patent 5,273,865. These compositions are said to be free of bromides, hydroxylamines and benzyl alcohol, to include a polyol compound having from 4 to 8 hydroxyl groups and which are useful for rapid access processing of photographic elements having emulsions with high content of silver bromide only. There is a continuing need in the photographic industry for a single-part color developer composition that is homogeneous, concentrated and stable. Such compositions would reduce the cost of packaging and storage of the diluted solutions, would avoid the need for multi-part mixing or agitation of multi-phase compositions and would offer the user a more attractive product. The present invention is directed to fulfill this felt need for a long time. This invention provides a breakthrough in the art with a single part color developer concentrate that is characterized as being homogeneous, having a pH of 7 to 13, and comprising: a) at least 0.06 mol / liter of an agent color developer in free base form, b) at least 0.05 mole / liter of an antioxidant by the color developer, c) water, d) a straight-chain, hydroxyl-containing organic solvent, water miscible or soluble in water, photographically inactive for the color developer in free base form, the organic solvent has a molecular weight of 50 to 200 and is present in the concentrate at a concentration such that the weight ratio of water to solvent is from 15:85 to 50:50 and e) a pH regulating agent that is miscible in the organic solvent. This invention also provides a photographic processing chemical equipment, characterized in that it comprises: a) the one-part color developer concentrate described above, and b) one or more of the following compositions: a photo bleaching composition, a bleaching / photographic fixing composition, a photographic fixing composition, and a photographic stabilizing or final rinsing composition. In addition, this invention includes a method for providing an image on a color silver halide photographic element comprising contacting a photographic silver halide photo element with, after dilution at least four times, the developer concentrate color of a single part described above. This color developing step in a photographic processing method can be followed by the removal of silver from the developed photographic color halide element, also as any other useful photoprocessing step known in the art. Still again, a method for preparing the homogeneous single-part color developer concentrate described above, comprises the steps of: A) mixing in water a color developer present as a sulfate salt, an antioxidant for the developer agent of color, an alkali metal base to provide alkali metal ions in at least stoichiometric ratio to the sulfate ions present in the sulfate salt and a hydroxyl-straight, water-miscible or water-soluble organic solvent, photographically inactive , the organic solvent has a molecular weight of 50 to 200 and is present in the concentrate at a concentration such that the weight ratio of water to the solvent is from 15:85 to 50:50 to form an insoluble alkali metal sulfate. in water in the solution and B) separating the water-insoluble alkali metal sulfate from the solution. The single-part color developer concentrate and the method for its preparation offer a variety of advantages over currently available or known photochemical compositions. The concentrate has minimal amount of water, to result in considerable savings in manufacturing, packaging and storage costs. In addition, it is a homogeneous composition which means that it is free of precipitates, suspensions or multiple phases of solvent. Thus, it is essentially a single-phase composition in manufacturing and during storage and use. It does not require vigorous agitation before use and can be dosed immediately and easily in a photographic or bath processing tank with minimal instruction or possibility of error. For example, the concentrate can be used in "automatic stuffing" processors where the processing composition is diluted and used as necessary. Importantly, it provides a one-part composition in such a manner that mixing of multiple parts, either liquid or solid, is avoided. The concentrate of this invention and the resulting concentrated color developer work composition have less odor than many conventional multi-part color developer compositions. Furthermore, it was unexpected that the formulation of the chemical compounds necessary for the development of color in a one part composition would result in no loss of chemical stability of any of those chemical compounds (such as the antioxidant and the color developer). and the pH. This was unexpected because it is well known in the art, that several such chemical compounds adversely affect each other and because of this they are usually separated into multiple parts for storage and packaging. The homogeneity indicated above has been obtained due to the discovery that the presence of a high concentration of sulfate ion is detrimental to the stability of the composition. It is likely that the sulfate ion causes precipitation when an attempt is made to reduce the water content and provide all the desired photochemical compounds in a one-part solution. A) Yes, once the source of the problem was determined, a way of removing the sulfate ion with a mixing sequence was discovered which is a breakthrough in the art. The sulfate ions were removed during a first stage of the formulation process, to provide a substantially clear solution that is ready to be used for the preparation of a concentrated working solution or as a filler. The sulfate ions are removed prematurely in the formulation of the composition by precipitating them in the presence of an alkali metal base and a straight chain organic solvent containing water-soluble or water-miscible hydroxyl. This solvent has a critical molecular weight of 50 to 200 for its effectiveness and solubility. The sulfate precipitate is easily removed before additional photochemical compounds are added to the solution. Preferably, the resulting color developing concentrate is essentially free of the sulfate ion (which means less than 0.005 moles / liter of sulfate ion). The homogenous single-part color developer concentrate of this invention is prepared by using a sequence of critical steps: In a first step, an aqueous solution of an appropriate color developer is prepared. This color developer is generally in the form of a sulfate salt. Other components of the solution may include an antioxidant for the color developer, an appropriate number of alkali metal ions (in an at least stoichiometric ratio to the sulfate ions) provided by an alkali metal base and an organic solvent containing hydroxyl miscible in water or soluble in water photographically inactive. This solvent is present in the final concentrate at a concentration such that the weight ratio of water to the organic solvent is from 15:85 to 50:50. In this environment, especially at high alkalinity, the alkali metal ions and sulfate ions form a sulfate salt which is precipitated in the presence of the hydroxyl-containing organic solvent. Then, the precipitated sulfate salt can be easily removed by using any appropriate liquid / solid phase separation technique (in which filtration, centrifugation or decanting are included). If the antioxidant is a liquid organic compound, two phases can be formed and the precipitate can be separated by discarding the aqueous phase. The color developer concentrates of this invention include one or more color developer agents that are well known in the art which, in oxidized form, will react with the dye-forming color couplers in the processed materials. Such color developing agents include, but are not limited to, aminophenols, p-phenylenediamines (especially, N, N-dialkyl-p-phenylene diamines) and others that are well known in the art such as EP 0 434 097 Al and EP 0 530 921 Al. It may be useful for the color developer agents to have one or more water soluble groups as are well known in the art. Additional details of such materials are provided in Research Disclosure, publication 38957, pages 592-639 (September 1996). This reference will be hereinafter referred to as "Research Disclosure". Preferred color developer agents include, but are not limited to, N, N-diethyl-p-phenylenediamine sulfate (KODAK CD-2 Color Developer), 4-amino-3-methyl-N- (2-sulfate) -metanesulfonamidoethyl) aniline, 4- (N-ethyl-Nb-hydroxyethylamino) -2-methylaniline sulfate (KODAK CD-4 Color Developer Agent), p-idroxyethylethylaminoaniline sulfate, 4- (N-ethyl-N-2-methanesulfonylaminoethyl) -2-methylphenylenediamine sesquisulfate (Agent KODAK CD-3 Color Developer), sesquisulfate of 4- (N-ethyl-N-2-methanesulfonylaminoethyl) -2-methylphenylenediamine, and others readily apparent to those skilled in the art. In order to protect the color developing agents from oxidation, one or more antioxidant agents are generally included in the color developer compositions.

They can be used either inorganic or organic antioxidants. Many classes of useful antioxidants are known, which include, but are not limited to sulfites (such as sodium sulfite, potassium sulfite, sodium bisulfite and potassium metabisulfite), hydroxylamine (and derivatives thereof), hydrazines , hydrazides, amino acids, ascorbic acid (and derivatives thereof), hydroxamic acids, amino ketones, mono- and polysaccharides, mono- and polyamines, quaternary ammonium salts, nitroxy radicals, alcohols and oximes. Also useful as antioxidants are 1,4-cyclohexadiones. Mixtures of compounds of the same or different classes of antioxidants can also be used if desired. Especially useful antioxidants are hydroxylamine derivatives as described for example in U.S. Patents 4,892,804, 4,876,174, 5,354,646 and 5,660,974 and 5,464,327. Many of these antioxidants are mono- and dialkylhydroxyalmines having one or more substituents on one or both alkyl groups. Particularly useful alkyl substituents include sulfo, carboxy, amino, sulfonamide, carbonamido, hydroxy substituents and other solubilizing substituents. More preferably, the hydroxylamine derivatives indicated may be mono- or dialkylhydroxylamines having one or more hydroxy substituents on the one or more alkyl groups. Representative compounds of this type are described for example in U.S. Patent 5,709,982, which have the structure I: OH OH R -f ?? fe-N-? 2 -) ñp-C ?? *)? r N- ^ p-R where R is hydrogen, a substituted or unsubstituted alkyl group of 1 to 10 carbon atoms, a hydroxyalkyl group substituted or not substituted by 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group of 5 to 10 carbon atoms or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms in the aromatic nucleus. Xi is -CR2 (OH) CHR! - and X2 is -CHRxCRa (OH) - wherein Rx and R2 are independently hydrogen, hydroxy, a substituted or unsubstituted alkyl group of 1 or 2 carbon atoms, a substituted hydroxyalkyl group or unsubstituted of 1 or 2 carbon atoms or Ri and R2 together represent the carbon atoms necessary to complete a saturated or unsaturated carbocyclic ring structure of 5 to 8 members, substituted or unsubstituted. Y is a substituted or unsubstituted alkylene group having at least 4 carbon atoms and has an even number of carbon atoms or Y is a substituted or unsubstituted divalent aliphatic group having a total pair group of carbon atoms and oxygen in the chain, provided that the aliphatic group has at least 4 atoms in the chain.

Also in structure I, m, n and p are independently 0 6 1. Preferably, each of y n is 1 and p is 0. Specific disubstituted hydroxylamine antioxidants include, but are not limited to: N, N-bis (2, 3-dihydroxyprolyl) hydroxylamine, N, N-bis (2-methyl-2,3-dihydroxy-propyl) hydroxylamine and N, N-bis (l-hydroxymethyl-2-hydroxy-3-phenylpropyl) hydroxylamine. The first compound is preferred. Many of the indicated antioxidants (organic or inorganic) are either commercially available or are prepared by using starting materials and procedures described in the references indicated above to describe the hydroxylamines. PH regulating agents are generally present in the color developing compositions of this invention to provide or maintain a desired alkaline pH of 7 to 13 and preferably 8 to 12. These pH regulating agents must be soluble in the organic solvent described. above and have a pKa of 9 to 13. Useful pH regulating agents include, but are not limited to carbonates, borates, tetraborates, glycine salts, triethanolamine, diethanolamine, phosphates and hydroxybenzoates. Alkali metal carbonates (such as sodium carbonate, sodium bicarbonate and potassium carbonate) are preferred. Mixtures of pH regulating agents can be used if desired. In addition to the pH regulating agents, the pH can also be raised or decreased to a desired value by using one or more acids or bases. It may be particularly desirable to raise the pH by adding a base such as a hydroxide (eg, sodium hydroxide or potassium hydroxide). An essential component of the color developer concentrates of this invention is a photographically inactive, water miscible straight or water miscible organic solvent that is capable of dissolving the color developer agents in their free base forms. Such organic solvents can be used individually or in combination and each preferably has a molecular weight of at least 50 and preferably at least 100 and in general 200 or less and preferably 150 or less. Such preferred solvents generally have from 2 to 10 carbon atoms (preferably from 2 to 6 carbon atoms and more preferably from 4 to 6 carbon atoms) and may additionally contain at least two nitrogen or oxygen atoms or by at least one of each heteroatom. The organic solvents are substituted with at least one hydroxy functional group and preferably at least two such groups. They are straight chain molecules, not cyclic molecules.

"Photographically inactive" means that organic solvents provide substantially no positive or negative effect on the color developer function of the concentrate. Useful organic solvents include, but are not limited to, polyols which include glycols (such as ethylene glycol, diethylene glycol and triethylene glycol), polyhydroxylamines (where polyalkanolamines are included) and alcohols (such as ethanol and benzyl alcohol). Glycols are preferred and ethylene glycol, diethylene glycol and triethylene glycol are more preferred. Of the alcohols, ethanol and benzyl alcohol are most preferred. The most preferred organic solvent is diethylene glycol. The amounts of water and organic solvent in the concentrate are carefully controlled to obtain all the desired results and to ensure a homogenous single-phase concentrate. If there is too much water, phase separation can occur. If there is too much organic solvent, the pH regulating agent and other salts will precipitate. The color developer concentrates of this invention may also include one or more of a variety of other additions that are commonly used in color developer compositions, which include alkali metal halides (such as potassium chloride, potassium bromide , sodium bromide and sodium iodide), metal sequestrant compositions (such as polycarboxylic acids or to polycarboxylic or polyphosphonate with or without cations lithium, magnesium and other small cations), auxiliary co-developer agents (such as pheidone-type compounds particularly for compositions black and white developers), defoamers, development accelerators, optical brighteners (such as traizinyl-ethylbenzene compounds), wetting agents, fragrances, stain-reducing agents, surfactants, defoamers, and water-soluble or water-dispersible color couplers, as will be more easily understood by those of experience in the art [see for example, Research Disclosure]. The amounts of such additives are well known in the art as well. The representative color developer concentrates of this invention are described below in example 1. The following table I shows the general and preferred amounts of the essential compounds of the color developer concentrates of this invention. Preferred ranges are listed in parentheses (). During color development, actual concentrations may vary depending on the chemical compounds extracted in the composition, fill rates, water losses, due to evaporation and transport of any preceding processing bath, or transport to the next processing bath.

TABLE I The color developer concentrates of this invention are useful for providing color development in a color photo silver silver halide element exposed in the form of printing or imaging, comprising a support and one or more layers of silver halide emulsion containing a print distribution or image formation of revealable silver halide emulsion beads. A wide variety of types of photographic elements (films and color reversal and color reversal papers and color animated films and prints) containing various types of emulsions can be processed using the present invention, the types of elements are well known in the art (see Research Disclosure). In particular, the invention can be used to process photographic papers in color of all types of emulsions in which the so-called "high chloride" and "low chloride" type emulsions and the so-called tabular grain emulsions are included. as well. The color developer solution can also be used in the processing of color reversal films and color negatives. The present invention is particularly useful for processing emulsions of high chloride content (greater than 70% in mol of chloride and preferably greater than 90% in mol of chloride based on total silver) in color photographic papers. Such color photo papers can have any useful amount of silver coated in the one or more emulsion layers and in some embodiments low silver content elements (ie, less than 0.8 g silver / square meter) are processed with the present invention. The layers of the photographic elements can have any useful binder material or vehicle as is well known in the art, in which various gelatins and other colloidal materials are included. The development or color development of a photographic silver halide element exposed in the manner of imaging is carried out by contacting the element with a color developer composition prepared in accordance with this invention, under conditions of time and temperature appropriate, in appropriate processing equipment, to produce the desired revealed image. Then, additional processing steps can be carried out by using conventional procedures, which include, but are not limited to, one or more of processing stop, bleaching, fixing, bleaching / fixing, washing (or rinsing), Stabilization and drying steps, in any particular desired order as would be well known in the art. Useful processing steps, conditions and materials useful for them are well known for the various processing protocols which include the conventional C-41 process of negative color films, RA-4 Process for processing color papers and process E -6 to process color investment films (see for example, Research Disclosure). The photographic elements processed in the practice of this invention can be single-layer or multi-layer color elements. The multilayer color elements typically contain sensitive dye image forming units in each of the three primary regions of the visible spectrum. Each unit may be comprised of a single emulsion layer or multiple emulsion layers sensitive to a given region of the spectrum. The layers of the element can be arranged in any of the various orders known in the art. In an alternative format, emulsions sensitive to each of the three primary regions of the spectrum can be arranged as a segmented sol layer. The elements may also contain other conventional layers such as filter layers, interlayers, gelatin base layers (which facilitate the adhesion of the sensitive emulsion), coatings and other layers readily apparent to those skilled in the art. U magnetic support can be included in the back side of conventional supports. Significantly more details of the element structure and components and appropriate methods of processing various types of elements are described in Researc Disclosure. Included in such teachings in the art is the use of various kinds of diano, yellow and magenta color couplers that can be used with the present invention (in which include magenta dye-forming couplers of pyrazolone and pyrazolothiazole type). In addition, the present invention can be used to process color photographic papers having pigmented resin-coated paper backings that are prepared with the usual internal and external sizing agents (which include alkyl ketene and higher fatty acid dimers), reinforcing agents and other known paper and coating additives. The color developer concentrate of this invention can be used in what are known as redox amplification processes, as described for example in U.S. Patents 5,723,268 and 5,702,873. The processing accog to the present invention can be carried out by using conventional deep tank containment processing solutions. Alternatively, it can be carried out by using what is known in the art as "low volume thin tank" or LVTT processing systems, which have either a stand and tank or automatic tray design. Such methods and processing equipment are described for example in the North American patent 5, 436,118 and publications indicated therein. The color development is generally followed by a bleaching or bleaching / fixing step using an appropriate silver bleaching agent. Numerous bleaching agents are known in the art to include hydrogen peroxide and other peracid compounds, persulfates, periodates and ferric ion salts or complexes with chelating ligands of polycarboxylic acid. Particularly useful chelating ligands include conventional polyamino-polycarboxylic acids which include ethylenediaminetetraacetic acid and others described in Research Disclosure, U.S. Patents 5,582,958 and 5,573,423. Biodegradable chelating ligands are also desirable because the impact on the environment is reduced. Useful biodegradable chelating ligands include, but are not limited to iminodiacetic acid or an alkyliminodiacetic acid (such as methyliminodiacetic acid), ethylenediamindisuccinic acid and similar compounds as described in EP-A-0 532,003, and ethylene diamine monosuccinic acid and similar compounds as described in U.S. Patent 5,691,120. The processing time and temperature used for each processing step of the present invention are generally those conventionally used in the art. For example, the color development is generally carried out at a temperature of 20 to 60 ° C. The overall color development time can be up to 40 minutes and preferably from 75 up to 450 seconds. The shorter overall color development times are desirable for processing color photo papers. The color developer concentrate of this invention can be formulated in a concentrated or filled working solution by appropriate dilution of up to 12 times. In general, the dilution ratio is 4 to 10 times, using water as a common diluent. Dilution can occur during or before processing. In one embodiment of this invention, the color developer concentrate is a chemical formulation in a photographic processing chemical equipment that may include one or more other photographic processing compositions (dry or liquid), which include, but are not limited to to a photographic bleaching composition, a bleaching / fixing photographic composition, a photographic fixing composition, and a stabilizing or rinsing photographic composition. Such additional compositions can be formulated in concentrated solutions or concentrated working solutions, or provided in dry form (eg, as a powder or tablet). Other processing compositions that can be included in such equipment for color photographic processing are investment compositions, conditioning compositions, pre-bleaching conditions, acid retention compositions and others readily apparent to those skilled in the photographic art. The processing equipment may also include various processing equipment, dosing devices, processing instructions, silver recovery devices and other conventional materials as would be readily apparent to those skilled in the art.

The following examples are provided to illustrate the practice of the invention and not to limit it in any way. Unless stated otherwise, the percentages are by weight.

Example 1: Colored paper color developer concentrate A homogeneous color developer concentrate of this invention (approximately 100 ml) was formulated as follows: A solution of sodium hydroxide (50% solution, 4 g) was added to a sesquisulfate solution of 4- (N-ethyl-N-2-methanesulfonylaminoethyl) -2-methylphenylenediamine (CD-3, 6.8 g) and diethylhydroxylamine (5.4 g) in water (6 g). Because diethylhydroxylamine is an organic liquid, two phases result. With stirring, diethylene glycol (50 g) is then added and a precipitate of sodium sulfate is observed. This precipitate was filtered from the solution, washed with 20 g of diethylene glycol and discarded. Then, the following components were added to the single-phase formulation: TABLE II After the addition of these components, the mixture was stirred until a homogeneous solution was obtained, filtered to remove a slight turbidity and packed as a color developer concentrate. This concentrate was essentially free of all sulfate ions.

Examples 2 and 3: Alternative color paper developer concentrates Example 1 is repeated except that ethylene glycol (example 2) or dipropylene glycol (example 3) is used instead of diethylene glycol. In both instances, a single-part homogeneous color developer concentrate is obtained.

Example 4: Preferred colored paper color developer concentrate A concentrate is prepared in a manner similar to that shown in Example 1 except that the diethylhydroxylamine was replaced with N, N'-bis (2,3-dihydroxypropyl) hydroxylamine (5.4 g. of 50% solution). The resulting concentrate (approximately 100 ml) was homogeneous and free of turbidity and sulfate ions.

Example 5: Preparation of the concentrated color developer and color paper processing composition A color developer composition useful for photoprocessing was prepared by diluting the concentrate described in Example 1 ten times with water. Then, this composition was used for the development of color in samples exposed to form of image formation or printing of commercially available KODAK EKTACOLOR EDGE 5 paper, the following processing protocol and conditions are used to obtain acceptable color images: color 38 ° C 45 seconds Blanking / fixing 35 ° C 45 seconds Washing (water) 35 ° C 90 seconds Bleaching / fixing was carried out using commercially available NR EKTACOLOR RA whitening fixative.

Example 6: Color negative film color developer concentrate A homogeneous color developer concentrate useful for processing color negative film was prepared as follows: A solution of sodium hydroxide (50% solution, 2.5 g) was added to a solution of KODAK CD-4 developer agent (4.5 g) and N, N'-bis (2,3-dihydroxypropyl) hydroxylamine (1.0 g, 50% solution), in water (3 g). Two phases result. Then, with stirring, diethylene glycol (50 g) is added and a precipitate of sodium sulfate is observed. This precipitate was filtered from the solution, washed with 20 g of diethylene glycol and discarded. Then, the following components were added to the single-phase formulation: TABLE III After the addition of these components, the mixture was stirred until a homogeneous solution was obtained, filtered to remove slight turbidity and packed as a color developer concentrate. This concentrate was essentially free of all sulfate ions.

Claims (15)

1. Claims 1. A single-part color developer concentrate, characterized in that it is homogeneous, having a pH of 7 to 13, and comprising: a) at least 0.06 moles / liter of a base color developer free, b) at least 0.05 moles / liter of an antioxidant for the color developing agent, c) water, d) a straight-chain organic solvent, substituted by hydroxyl, water-miscible or water-soluble, having a weight molecular weight from 50 to 200 and is present in the concentrate at a concentration such that the weight ratio of water to the solvent is from 15:85 to 50:50, and e) a pH regulating agent that is soluble in the organic solvent .
2. 2. The color developer concentrate according to claim 1, characterized in that the color developer is present in an amount of 0.06 to 0.3 mole / liter, the antioxidant is present in an amount of 0.05 to 1 mole / liter and the Weight ratio of water to organic solvent is from 30:70 to 40:60.
3. 3. The developer concentrate according to any of claims 1 or 2, characterized in that the antioxidant is represented by the structure I: OH OH
4. R - ??; fc-N- < rx2 *) ρ-X?) ^ - N- (X 2) n] p R wherein R is hydrogen, an alkyl group, a hydroxyalkyl group, a cycloalkyl group or an aryl group, R x and R 2 are independently hydrogen, hydroxy, an alkyl group or a hydroxyalkyl group or Ri and R2 together represent the carbon atoms necessary to complete a 5 to 8 member carboxylic ring structure, Xi is -CR2 (OH) CHRi-, X2 is -CHR? CR2 (OH) - and m, n and p are independently 0 or 1. 4. The color developer concentrate according to any of claims 3, characterized in that the organic solvent is an aliphatic compound having a molecular weight of 100 to 200, and has 2 to 10 carbon atoms.
5. 5. The color developer concentrate according to any of claims 1 to 4, characterized in that the organic solvent is ethylene glycol, diethylene glycol, triethylene glycol, ethanol or benzyl alcohol.
6. 6. The color developer concentrate according to any of claims 1 to 5, characterized in that the pH regulating agent is a carbonate.
7. 7. The color developer concentrate according to any of claims 1 to 6, characterized in that it comprises one or more of the following components: e) chloride ions, f) bromide ions, g) a metal ion sequestering composition, h) an agent optical brightening of triazinilestilbene, i) a polyalkanolamine or j) a fragrance. A chemical photographic processing equipment characterized in that it comprises: a) the single-part color developer concentrate according to any one of claims 1 to 7 and b) one or more of the following compositions: a photo bleaching composition, a bleaching / photographic fixing composition, a photographic fixing composition, or a final photographic stabilization or rinse composition. 9. A method for providing an image on a photographic silver halide element characterized in that it comprises contacting a photographic silver halide material with, after at least four times dilution, the one-part color developer concentrate. according to any one of claims 1 to 7. 10. A method of photographic processing, characterized in that it comprises the steps of: A) developing color of a silver halide element of photographic color exposed in the form of imaging or printing with, after a dilution of at least four times, the one-part color developer concentrate according to any of claims 1 to 7, and B) removal of the silver from the silver halide element of photographic color developed in color. 11. A method for the preparation of a one-part color developer composition, sulfate-free, ready to use, homogeneous, characterized in that it comprises the steps of: A) mixing in water a color developer present as a sulfate salt, an antioxidant for the color developer, alkali metal ions in at least a stoichiometric ratio to the sulfate salt and a water-soluble or water-soluble straight-chain organic solvent having a molecular weight of 50 to 200, and present at a concentration such that the weight ratio of the water to the solvent is from 15:85 to 50:50 to form an alkali metal sulfate in the solution and B) to remove the alkali metal sulfate from the solution. 12. The method according to claim 11, characterized in that the alkali metal ions are provided as part of an alkali metal hydroxide. The method according to claim 11 or claim 12, characterized in that it further comprises the step of: C) adding to the solution one or more of the following components: a pH regulating agent, chloride ions, bromide ions, a metal ion sequestering composition, an optical triazinyl-ethylbenzene brightening agent, a polyalkanolamine or a fragrance. The method according to any of claims 11 to 13, characterized in that the antioxidant is represented by the structure I: OH OH wherein R is hydrogen, an alkyl group, a hydroxyalkyl group, a cycloalkyl group or an aryl group, Ri and R2 are independently hydrogen, hydroxy, an alkyl group or a hydroxyalkyl group or Ri and R2 together represent the carbon atoms necessary for completing a 5 to 8 member carboxylic ring structure, Xx is -CR2 (OH) CHRi-, X2 is -CHR? CR2 (OH) - and m, n and p are independently 0 or 1. 15. A color developer concentrate of a only part, characterized in that it is homogeneous, essentially free of sulfate ion, has a pH of 7 to 13 and that comprises: a) at least 0.06 moles / liter of a color developer in the form of a free base, b) less 0.05 moles / liter of an antioxidant for the color developer, c) water, d) a water-soluble or water-soluble hydroxyl-substituted, straight-chain organic solvent having a molecular weight of 50 to 200 and is present in the concentrate at a concentration of so that the weight ratio of water to the solvent is from 15:85 to 50:50, and e) a pH regulating agent that is soluble in the organic solvent.