Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
  • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
  • G03C5/395—Regeneration of photographic processing agents other than developers; Replenishers therefor
  • G03C5/3958—Replenishment processes or compositions, i.e. addition of useful photographic processing agents
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C7/00—Multicolour photographic processes or agents therefor; Regeneration of such processing agents; Photosensitive materials for multicolour processes
  • G03C7/30—Colour processes using colour-coupling substances; Materials therefor; Preparing or processing such materials
  • G03C7/44—Regeneration; Replenishers

Definitions

• This invention relates to the processing of silver halide photographic materials. More specifically, it relates to a method of and composition for replenishing a bleach-fix solution.
• Silver halide light-sensitive materials in which the primary silver halide species is silver chloride are generally processed by color developing and bleach-fixing the material.
• the bleach-fix solution generally contains a ferric complex salt of an organic chelating compound such as ethylenediaminetetraacetic acid (EDTA) and a fixing agent such as thiosulfate.
• EDTA ethylenediaminetetraacetic acid
• the bleach-fix is replenished at a low rate in an effort to minimize the effluent being discharged to the sewer.
• all bleach-fix solutions having a replenishment rate of 53.8 ml/m2 or less use ammonium thiosulfate as the fixing agent.
• Efforts to remove or reduce the ammonia by substituting a different univalent cation while maintaining a low replenishment rate have always failed due to the low solubility of non-ammonium systems that contain a ferric salt of an organic chelating agent and a fixing agent.
• U.S. Patent 4,954,426 discusses a low replenishment rate bleach-fix solution with not less than 80 mole % of the total non-metallic cations present in the replenisher for the bleach-fix solution being ammonium ions.
• U.S. Patent 3,706,561 describes a low ammonia bleach-fix having a higher pH to circumvent solubility problems. The use of a higher pH retards bleaching and the use of a secondary ligand is therefore required.
• bleach-fix replenishers have been one-part solutions.
• KODAK EKTACOLOR RA Bleach-Fix D-Rep which has an effective replenishment rate of 19.4 ml/m2, is a three-part replenisher.
• This system uses ammonium thiosulfate as the fixing component.
• Japanese Kokai SHO 55(1980)-79446 discusses the use of a two-part replenishment system to achieve a low replenishment rate. With this system, a 90 second bleach-fix is used and the pH of the bleach-fix is always maintained above 6.5.
• Japanese Kokai SHO 55(1980)-77743 also discusses a two-part replenishment system. The pH of the bleach-fix of this system is always maintained above 7.0, which results in poorer bleaching as discussed previously.
• U.S. Patent 5,055,382 describes a three-part bleach regeneration kit, however, the first part is an alkaline solution containing a buffering agent and an aminopolycarboxylic acid which is added to the spent bleach-fix solution before electrolytic recovery of the silver therefrom.
• the other two parts contain, respectively, an iron salt and a thiosulfate, and are also added to the spent bleach-fix solution.
• the problem to be solved with this invention is to provide a replenisher for a bleach-fix solution which has a low or no ammonium ion content and which can be replenished at a very low rate.
• the replenisher must be able to maintain a bleach-fix bath which can rapidly bleach-fix a photographic element and which has a pH under 6.5 to maintain adequate bleaching ability.
• This invention provides a replenisher for a bleach-fix solution, said replenisher comprising discrete and separate parts A, B, and C, wherein part A contains thiosulphate and a preservative; part B contains a ferric aminopolycarboxylic acid complex; and part C contains an acid, and the total ammonium ion content of parts A and B is less than 50 mole % of the total cations.
• the thiosulphate consists of sodium or potassium thiosulphate and the ferric aminopolycarboxylic acid complex consists of a ferric sodium or ferric potassium aminopolycarboxylic acid complex.
• This invention further provides a method of replenishing a bleach-fix solution comprising adding to the bleach-fix solution a replenisher as described above, while maintaining the pH of the bleach-fix solution between 5.5 and 6.5. It also provides a method of bleaching and fixing a photographic element comprising processing the photographic element in a bleach-fix solution for 45 seconds or less, wherein the bleach-fix solution is replenished with a replenisher as described above; and wherein the pH of the bleach-fix solution is maintained between 5.5 and 6.5. In one embodiment of this method, the photographic element has a silver chloride content of greater than 90 mole % and a silver content of less than 0.86 g/m2.
• the three-part replenishment system of this invention provides a replenisher in which low ammonia or non ammonium constituents are stable at high concentrations.
• Ammonium thiosulfate can be replaced either entirely or in part by sodium or potassium thiosulfate in a bleach-fix formulation.
• Ferric ammonium aminopolycarboxylic acids can also be replaced with potassium or sodium aminopolycarboxylic acids if so desired. This allows for the removal or reduction of ammonia in a bleach-fix solution while maintaining a replenishment rate less than 27 ml/m2. It also allows for the formulation of a bleach-fix solution which operates at a pH less than 6.5 and requires a processing time no greater than 45 seconds.
• the replenisher of this invention comprises three separate and discrete parts.
• Part A contains a thiosulfate and a preservative
• Part B contains a ferric aminopolycarboxylic acid
• Part C contains an acid.
• the thiosulfate can be an alkali metal thiosulfate, with sodium or potassium thiosulphate being preferred. It can also be a combination of an alkali metal thiosulphate with ammonium thiosulphate. If ammonium thiosulphate is used, the mole % of ammonium cations contained in Parts A and B must be less than 50 mole % of the total cations present, and preferably less than 20 mole %. Preferably, the thiosulphate does not contain any ammonium ion.
• the concentration of thiosulphate should be about .75 mol/l to about 5.0 mol/l, with 2.0 mol/l to 3.0 mol/l being preferred.
• Part A should also contain a preservative.
• the preferred preservative is sulfite, some examples of which are sodium sulfite, sodium metabisulfite, potassium sulfite, lithium sulfite, ammonium sulfite, sodium bisulfite, ammonium bisulfite, potassium metabisulfite, and sodium formaldehyde bisulfite.
• the amount of the preservative may be from .05 mol/l to 1.0 mol/l, with .45 mol/l to .55 mol/l being preferred.
• a mixture of preservatives may be also be used.
• Part A may also contain other additives such as, among others, bleach accelerators, fix accelerators, free ligand, and buffering agents.
• the pH of Part A may be 4 to 10.
• the aminopolycarboxylic acid of the ferric aminopolycarboxylic acid complex in Part B can be any such acid which is useful in bleaching silver halide emulsions.
• useful aminopolycarboxylic acids include, but are not limited to, the following:
• the ferric aminopolycarboxylic acid complex can be a ferric ammonium aminopolycarboxylic acid complex or a complex with an alkali metal such as sodium or potassium. It may also be a mixture of the above. A non-ammonium complex is preferred for environmental reasons.
• the concentration of the ferric aminopolycarboxylic acid complex should be from about .05 mol/l to about 2.0 mol/l, with 1.25 mol/l to 1.75 mol/l being preferred.
• Part B can also contain various additives such as excessive ligand and buffers.
• the pH of this solution may be 3 to 10.
• the third component, Part C is an acid.
• the acid must be one which is suitable for use in photographic processing solutions.
• the pH of Part C should be such that the pH of the bleach-fix solution is maintained at a pH of 5.5 to 6.5 while maintaining a low replenishment rate.
• suitable acids are acetic, propionic, citric, or succinic, sulfonic, and nitric acid. Acetic acid is preferred. It is this separate acid component which allows for the low replenishment rate of this replenisher. Because the other parts are not required to have a low pH, the concentration of the thiosulphate and the ferric aminopolycarboxylic acid complex can be higher without losing solubility.
• Each part of the replenisher should be added directly to the bleach-fix solution with no pre-mixing or dilution.
• One of the objects of this invention is to provide a replenisher having the lowest possible replenishment rate while still maintaining a stable and effective bleach-fix solution and replenisher.
• the total amount of the replenisher which must be added to the bleach-fix solution is dependent on the type of cation in Parts A and B and on the amount of carryover from the preceding solution. Carryover is the amount of liquid per square unit which is carried by the photographic element from the preceding bath into the bleach-fix solution.
• the preceding bath may be any one of several different baths, such as a developer bath, a stop bath, or a wash bath. The invention herein is most useful in the situation where the preceding bath is alkaline.
• the amount of replenisher used per square unit of photographic material processed is about 0.5 to 1 times the carryover from the preceding solution. For example, if the carryover is 43 ml/m2, then 21.5 to 43 mls of replenisher should be added for each square meter of the photographic element which is processed. Of the total amount of replenisher added, the preferred ratio of Part A/Part B/Part C is approximately 3/1/1.
• the amount of replenisher used per square unit of photographic material processed is about 0.625 to 1.25 times the carryover from the preceding solution. Therefore, if the carryover is 43 ml/m2, then about 26.9 to 53.8 mls of replenisher should be added for each square meter of film which is processed. Of the total amount of replenisher added, the preferred ratio of Part A/PartB/PartC is approximately 3/1/1.
• the amount of replenisher used per square unit of photographic material processed is about 2.5 to 5 times the carryover from the preceding solution. Therefore, if the carryover is 43 ml/m2, then 107.5 to 215 mls of replenisher should be added for each square meter of film which is processed. Of the total amount of replenisher added, the preferred ratio of Part A/Part B/Part C is approximately 3/6/1.
• the bleach-fix solution to be replenished can be maintained at a pH between 5.5 and 6.5, and the working strength of the bleach-fix solution can be maintained as follows: .05 mol/l to 1.0 mol/l thiosulfate, .01 mol/l to 0.5 mol/l preservative, and .025 mol/l to .25 mol/l ferric aminopolycarboxylic acid complex; with 0.4 mol/l to 0.65 mol/l thiosulfate; 0.075 mol/l to 0.2 mol/l preservative; and 0.025 mol/l to 0.2 mol/l ferric aminopolycarboxylic acid complex being preferred. This allows for a bleach-fix time of 45 seconds or less.
• the photographic elements to be processed can contain any of the conventional silver halides as the photosensitive material, for example, silver chloride, silver bromide, silver bromoiodide, silver chlorobromide, silver chloroiodide, and mixtures thereof.
• the photographic element is a high chloride element, containing at least 90 mole % silver chloride.
• the photographic elements most useful with this invention have a silver content of less than .86 g/m2.
• the photographic elements can be single color elements or multicolor elements.
• Multicolor elements typically contain dye image-forming units sensitive to each of the three primary regions of the visible spectrum. Each unit can be comprised of a single emulsion layer or of multiple emulsion layers sensitive to a given region of the spectrum.
• the layers of the element, including the layers of the image-forming units, can be arranged in various orders as known in the art.
• the emulsions sensitive to each of the three primary regions of the spectrum can be disposed as a single segmented layer, e.g., as by the use of microvessels as described in Whitmore, U.S. Patent 4,362,806, issued December 7, 1982.
• the element can contain additional layers such as filter layers, interlayers, overcoat layers, subbing layers, and the like.
• the silver halide emulsions employed in the elements of this invention can be either negative-working or positive-working.
• suitable emulsions and their preparation are described in Research Disclosure Sections I and II and the publications cited therein.
• Some of the suitable vehicles for the emulsion layers and other layers of elements of this invention are described in Research Disclosure Section IX and the publications cited therein.
• the silver halide emulsions can be chemically and spectrally sensitized in a variety of ways, examples of which are described in Sections III and IV of the Research Disclosure.
• the elements of the invention can include various couplers including, but not limited to, those described in Research Disclosure Section VII, paragraphs D, E, F, and G and the publications cited therein. These couplers can be incorporated in the elements and emulsions as described in Research Disclosure Section VII, paragraph C and the publications cited therein.
• the photographic elements of this invention or individual layers thereof can contain among other things brighteners (examples in Research Disclosure Section V), antifoggants and stabilizers (examples in Research Disclosure Section VI), antistain agents and image dye stabilizers (examples in Research Disclosure Section VII, paragraphs I and J), light absorbing and scattering materials (examples in Research Disclosure Section VIII), hardeners (examples in Research Disclosure Section X), plasticizers and lubricants (examples in Research Disclosure Section XII), antistatic agents (examples in Research Disclosure Section XIII), matting agents (examples in Research Disclosure Section XVI) and development modifiers (examples in Research Disclosure Section XXI).
• the photographic elements can be coated on a variety of supports including, but not limited to, those described in Research Disclosure Section XVII and the references described therein.
• Photographic elements can be exposed to actinic radiation, typically in the visible region of the spectrum, to form a latent image as described in Research Disclosure Section XVIII and then processed to form a visible dye image, examples of which are described in Research Disclosure Section XIX.
• Processing to form a visible dye image includes the step of contacting the element with a color developing agent to reduce developable silver halide and oxidize the color developing agent. Oxidized color developing agent in turn reacts with the coupler to yield a dye.
• the color developing solutions typically contain a primary aromatic amino color developing agent.
• These color developing agents are well known and widely used in variety of color photographic processes. They include aminophenols and p-phenylenediamines.
• aminophenol developing agents examples include o-aminophenol, p-aminophenol, 5-amino-2-hydroxytoluene, 2-amino 3-hydroxytoluene, 2-hydroxy-3-amino-1,4-dimethylbenzene, and the like.
• Particularly useful primary aromatic amino color developing agents are the p-phenylenediamines and especially the N-N-dialkyl-p-phenylenediamines in which the alkyl groups or the aromatic nucleus can be substituted or unsubstituted.
• Examples of useful p-phenylenediamine color developing agents include: N-N-diethyl-p-phenylenediaminemonohydrochloride, 4-N,N-diethyl-2-methylphenylenediaminemonohydrochloride, 4-(N-ethyl-N-2-methanesulfonylaminoethyl)-2-methylphenylenediamine sesquisulfate monohydrate, 4-(N-ethyl-N-2-hydroxyethyl)-2-methylphenylenediamine sulfate, 4-N, N-diethyl-2, 2'-methanesulfonylaminoethylphenylenediamine hydrochloride, and the like.
• color developing solutions typically contain a variety of other agents such as alkalies to control pH, bromides, iodides, benzyl alcohol, anti-oxidants, anti-foggants, solubilizing agents, brightening agents, and so forth.
• Photographic color developing compositions are employed in the form of aqueous alkaline working solutions having a pH of above 7 and most typically in the range of from about 9 to about 13. To provide the necessary pH, they contain one or more of the well known and widely used pH buffering agents, such as the alkali metal carbonates or phosphates. Potassium carbonate is especially useful as a pH buffering agent for color developing compositions.
• the processing step described above gives a negative image.
• this step can be preceded by development with a non-chromogenic developing agent to develop exposed silver halide, but not form dye, and then uniformly fogging the element to render unexposed silver halide developable.
• a direct positive emulsion can be employed to obtain a positive image.
• a separate pH lowering solution referred to as a stop bath
• a stabilizer bath is commonly employed for final washing and hardening of the bleached and fixed photographic element prior to drying. Conventional techniques for processing are illustrated by Research Disclosure, Paragraph XIX.
• Preferred processing sequences for color photographic elements include the following:
• a bath can be employed prior to color development, such as a prehardening bath, or the washing step may follow the stabilizing step.
• reversal processes which have the additional steps of black and white development, chemical fogging bath, light re exposure, and washing before the color development are contemplated.
• a bleach-fix tank (Bleach-Fix 2) was prepared that simulates the tank that would be formed if the following replenisher solutions were used at the indicated rates:
• a simulated seasoned bleach-fix solution containing ammonium thiosulfate (Bleach-Fix 1) was also prepared.
• EKTACOLOR EDGE® paper was processed using Kodak Process RA-4 in which the processing times and steps are as follows: Developer 45 Seconds 95°F Bleach-Fix (Bleach-Fix 1 or Bleach-Fix 2) 45 Seconds 95°F Wash 90 Seconds 95°F
• the silver remaining in the paper was determined by measuring the IR density of both the D-Min and D-Max of the paper and calculating the difference. This resulting difference was used as the measurement for retained silver. A fully bleached sample would be expected to have a difference of 0.06 or less.
• the retained silver left in the paper is given in Table II. TABLE II Silver (IR DMax - DMin) Remaining In Paper After Processing Bleach-Fix Bath Silver (DMax - DMin) 1 (Comparative) 0.06 2 (Invention) 0.06
• Bleach-Fix Replenisher 3 represents the one-part replenisher solution that would be necessary to yield Bleach-Fix Tank 4 (which is identical to Bleach-Fix Tank 2 used in Table I) assuming a replenishment rate of 53.8 ml/m2 and a carryover of 43 ml/m2. Both solutions 3 and 4 were stored at room temperature for 8 weeks. A precipitate (Ferric Sodium EDTA) was observed in Bleach-Fix Replenisher 3 but not in Bleach-Fix Tank 4. These results demonstrate that a one part bleach-fix replenisher such as Bleach-Fix Replenisher 3 cannot be used to replenish Bleach-Fix Tank 4 due to the instability of the replenisher solution. The present invention circumvents this problem.
• EKTACHROME Radiance paper was processed using Kodak Process R-3 in which the processing times and steps are as follows: First Developer 75 Seconds 38°C First Wash 90 Seconds 35 - 41°C Reexposure With Fluorescent Light 5 to 10 Seconds Color Developer 135 Seconds 38°C Second Wash 45 Seconds 25 - 41°C Bleach-Fix (Bleach-Fix 5 or Bleach-Fix 6) 120 Seconds 38°C Final Wash 135 Seconds 25 - 41°C Dry As Needed At Less Than 71°C
• the silver remaining in the paper was determined by measuring the IR density of both the D-Min and D-Max of the paper and calculating the difference. This resulting difference is used as the measurement for retained silver. A fully bleached sample would be expected to have a difference of 0.06 or less.
• the retained silver left in the paper is given in Table V. TABLE V Silver (IR DMax - DMin) Remaining In Paper After Processing Bleach-Fix Bath Silver (DMax - DMin) 5 (Comparative) 0.06 2 (Invention) 0.06
• Bleach-Fix Replenisher 7 represents the one-part replenisher solution that would be necessary to yield Bleach-Fix Tank 8 (which is identical to Bleach-Fix Tank 6 used in Table IV) assuming a replenishment rate of 215 ml/m2 and a carryover of 32.3 ml/m2. Both solutions, Bleach-Fix Replenisher 7 and Bleach-Fix Tank 8 were stored at room temperature for 8 weeks. A precipitate (Ferric Sodium EDTA) was observed in Bleach-Fix Replenisher 7 but not in Bleach-Fix Tank 8. These results demonstrate that a one part bleach-fix replenisher such as Bleach-Fix Replenisher 7 cannot be used to replenish Bleach-Fix Tank 8 due to instability of the replenisher solution. The present invention circumvents this problem.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=25494697

Family Applications (1)

Country Status (5)

Citations (3)

• 1993
  • 1993-09-02 CA CA002105444A patent/CA2105444A1/en not_active Abandoned
  • 1993-09-27 KR KR1019930019822A patent/KR940007602A/ko not_active Application Discontinuation
  • 1993-09-28 MX MX9306008A patent/MX9306008A/es unknown
  • 1993-09-28 EP EP93115608A patent/EP0590583A1/de not_active Withdrawn
  • 1993-09-29 JP JP5242549A patent/JPH06202292A/ja active Pending

Patent Citations (3)

Also Published As

Similar Documents

Legal Events