US3061433A - Process and solution for bleaching photographic images - Google Patents
Process and solution for bleaching photographic images Download PDFInfo
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- US3061433A US3061433A US833671A US83367159A US3061433A US 3061433 A US3061433 A US 3061433A US 833671 A US833671 A US 833671A US 83367159 A US83367159 A US 83367159A US 3061433 A US3061433 A US 3061433A
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- acetic acid
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- 238000000034 method Methods 0.000 title claims description 11
- 238000004061 bleaching Methods 0.000 title claims description 10
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 59
- KMUONIBRACKNSN-UHFFFAOYSA-N potassium dichromate Chemical compound [K+].[K+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O KMUONIBRACKNSN-UHFFFAOYSA-N 0.000 claims description 36
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 19
- 239000001117 sulphuric acid Substances 0.000 claims description 19
- 235000011149 sulphuric acid Nutrition 0.000 claims description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 19
- 239000000463 material Substances 0.000 claims description 16
- 229910052709 silver Inorganic materials 0.000 claims description 11
- 239000004332 silver Substances 0.000 claims description 11
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 8
- 239000000243 solution Substances 0.000 description 29
- 229960000583 acetic acid Drugs 0.000 description 18
- 239000007844 bleaching agent Substances 0.000 description 15
- 239000010802 sludge Substances 0.000 description 7
- KRVSOGSZCMJSLX-UHFFFAOYSA-L chromic acid Substances O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 description 5
- 239000002253 acid Substances 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 4
- AWJWCTOOIBYHON-UHFFFAOYSA-N furo[3,4-b]pyrazine-5,7-dione Chemical compound C1=CN=C2C(=O)OC(=O)C2=N1 AWJWCTOOIBYHON-UHFFFAOYSA-N 0.000 description 4
- 238000010186 staining Methods 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000008030 elimination Effects 0.000 description 3
- 238000003379 elimination reaction Methods 0.000 description 3
- 239000000839 emulsion Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- -1 silver halide Chemical class 0.000 description 3
- VQWFNAGFNGABOH-UHFFFAOYSA-K chromium(iii) hydroxide Chemical compound [OH-].[OH-].[OH-].[Cr+3] VQWFNAGFNGABOH-UHFFFAOYSA-K 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- IOLCXVTUBQKXJR-UHFFFAOYSA-M potassium bromide Chemical compound [K+].[Br-] IOLCXVTUBQKXJR-UHFFFAOYSA-M 0.000 description 2
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- VNPBXWLZWAMGEO-UHFFFAOYSA-N 1,1-diethyl-2-(2-methylphenyl)hydrazine Chemical compound CCN(CC)NC1=CC=CC=C1C VNPBXWLZWAMGEO-UHFFFAOYSA-N 0.000 description 1
- PPAVKVHVVGUHDY-UHFFFAOYSA-N 2-hydroxy-1,3,2$l^{5}-dioxaphosphonane 2-oxide Chemical compound OP1(=O)OCCCCCCO1 PPAVKVHVVGUHDY-UHFFFAOYSA-N 0.000 description 1
- GXCLVBGFBYZDAG-UHFFFAOYSA-N N-[2-(1H-indol-3-yl)ethyl]-N-methylprop-2-en-1-amine Chemical compound CN(CCC1=CNC2=C1C=CC=C2)CC=C GXCLVBGFBYZDAG-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 101150089644 Rnls gene Proteins 0.000 description 1
- 239000004133 Sodium thiosulphate Substances 0.000 description 1
- SOIFLUNRINLCBN-UHFFFAOYSA-N ammonium thiocyanate Chemical compound [NH4+].[S-]C#N SOIFLUNRINLCBN-UHFFFAOYSA-N 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001844 chromium Chemical class 0.000 description 1
- 239000013065 commercial product Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- CMMUKUYEPRGBFB-UHFFFAOYSA-L dichromic acid Chemical class O[Cr](=O)(=O)O[Cr](O)(=O)=O CMMUKUYEPRGBFB-UHFFFAOYSA-L 0.000 description 1
- MCPLVIGCWWTHFH-UHFFFAOYSA-M disodium;4-[4-[[4-(4-sulfoanilino)phenyl]-[4-(4-sulfonatophenyl)azaniumylidenecyclohexa-2,5-dien-1-ylidene]methyl]anilino]benzenesulfonate Chemical compound [Na+].[Na+].C1=CC(S(=O)(=O)O)=CC=C1NC1=CC=C(C(=C2C=CC(C=C2)=[NH+]C=2C=CC(=CC=2)S([O-])(=O)=O)C=2C=CC(NC=3C=CC(=CC=3)S([O-])(=O)=O)=CC=2)C=C1 MCPLVIGCWWTHFH-UHFFFAOYSA-M 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000012362 glacial acetic acid Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- CMCWWLVWPDLCRM-UHFFFAOYSA-N phenidone Chemical compound N1C(=O)CCN1C1=CC=CC=C1 CMCWWLVWPDLCRM-UHFFFAOYSA-N 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 150000003378 silver Chemical class 0.000 description 1
- GCLGEJMYGQKIIW-UHFFFAOYSA-H sodium hexametaphosphate Chemical compound [Na]OP1(=O)OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])O1 GCLGEJMYGQKIIW-UHFFFAOYSA-H 0.000 description 1
- 235000011121 sodium hydroxide Nutrition 0.000 description 1
- 239000001488 sodium phosphate Substances 0.000 description 1
- AKHNMLFCWUSKQB-UHFFFAOYSA-L sodium thiosulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=S AKHNMLFCWUSKQB-UHFFFAOYSA-L 0.000 description 1
- 235000019345 sodium thiosulphate Nutrition 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 1
- 229910000406 trisodium phosphate Inorganic materials 0.000 description 1
- 235000019801 trisodium phosphate Nutrition 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
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
- G03C5/40—Chemically transforming developed images
- G03C5/44—Bleaching; Bleach-fixing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
- Y10S430/164—Rapid access processing
Definitions
- Rapid processing photographic projectors of the kind here concerned can develop and project a photograph in as short a time as two seconds. Where better resolution and archival quality are required, black and white processing requires from four to six seconds and colour processing presently requires about fifteen seconds.
- the exposed photographic material is subjected to successive processing solutions whereby a positive image is formed in the material and the material is immediately passed through an optical projection section whereby the projected positive image may be viewed.
- the processing should be by the so-called reversal method, is.
- the initial latent image resultant on light exposure is developed to a negative record in silver; this silver is bleached out and the residual silver halide is developed.
- a colour image is to be obtained it is necessary to bleach out the developed silver (existing either as negative or positive image).
- the processing solutions are applied by means of jet applications operating in a single processing zone. This leads to some problems.
- the developers used are normally highly alkaline and the most eifective silver bleach baths are those based on chromic acid.
- highly alkaline developer which, when followed by the use of the chromic acid bleach solution, slowly results in a buildup of a complex chromium hydroxide sludge which has been found to cause severe blockage of the jets themselves and interfere with the quality of the processing due to its formation on the interior surfaces of the processing zone. In some cases the machine ceases to function.
- oxidising acid such as the chromic acid previously mentioned in order successfully to dissolve the silver image in a short period of time.
- This oxidising acid usually consists of a mixture of sulphuric acid and potassium dichromate in various proportions which gives a complex oxidising acid containing chromic acids, dichromic acids, etc. The precise mechanism of this chemical reaction is not agreed to by all the various authorities.
- a bleach solution for use in rapid processing photographic projectors in which the elapsed time from exposure to projection is less than thirty seconds, consisting of potassium dichromate, acetic acid, and sulphuric acid so proportioned that photographic film is rapidly processed with the production of a negligible amount of sludge and the elimination of staining in the event of over-bleaching.
- the bleach solution characteristic of this invention contains, in aqueous solution, 0.5 to 5% by weight potassium dichromate, 0.5 to 10% by weight acetic acid and 2 to 15% by weight sulphuric acid.
- the processing time is 2 to 6 seconds it is preferred that the solution should contain less than 2% potassium dichromate, lessthan 4% acetic acid, and less than 6% sulphuric acid.
- an aqueous solution comprising:
- Photographic colour film comprising a silver halide emulsion containing a coupling compound which, on de- Jet 1.Develper Hexamethylene phosphate (the commercial product Calgon (in 20% solution) mls 15 Trisodium phosphate (cryst.) g 80 Sodium sulphite anhydrous in aqueous solution) mls 50 Potassium bromide (10% aqueous solution) rnls l0 Diethylaminotoluidine g 4 1-phenyl-3-pyrazolidone (0.625 g. +6 ml. of 10% anhydrous sodium sulphite in water, made up to 100 cc. with water) mls 10 Water to make, 1 litre.
- Develper Hexamethylene phosphate the commercial product Calgon (in 20% solution) mls 15 Trisodium phosphate (cryst.) g 80 Sodium sulphite anhydrous in aqueous solution) ml
- the aforesaid type of material yields images in colour on a white background.
- the step of bleaching a developed silver image by treating the photographic material with a bleach solution consisting of potassium dichromate, acetic acid, sulphuric acid and water in which the percentage of potassium dichromate is at least half a percent and not more than five percent by weight, anhydrous acetic acid is at least half a percent and not more than ten percent by weight, anhydrous sulphuric acid is at least two percent and not more than fifteen percent by weight, and the balance is water to make up one hundred percent.
- a bleach solution consisting of potassium dichromate, acetic acid, sulphuric acid and water in which the percentage of potassium dichromate is at least half a percent and not more than five percent by weight, anhydrous acetic acid is at least half a percent and not more than ten percent by weight, anhydrous sulphuric acid is at least two percent and not more than fifteen percent by weight, and the balance is water to make up one hundred percent.
- a process for the rapid processing of photographic materials the steps of exposing the photographic material, developing a silver image by treating the photographic material with a developer solution, bleaching the developed silver image by treating the photographic material with a bleach solution consisting of potassium dichromate, acetic acid, sulphuric acid and water in which the percentage of potassium dichromate is at least half a percent and not more than five percent by weight, anhydrous acetic acid is at least half a percent and not more than ten percent by weight, anhydrous sulphuric acid is at least two percent and not more than fifteen percent by weight, and the balance is water to make up one hundred percent, washing the photographic materials with a wash solution and drying the photographic materials, all with a time lapse of less than twenty seconds.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Silver Salt Photography Or Processing Solution Therefor (AREA)
Description
United States Malt Patented Oct. 30, 1962 3,061,433 PROCESS AND SOLUTION FOR BLEACHING PHOTOGRAPHIC IMAGES Robert Charles Morris Smith, llford, England, and
Eustace Raymond Towuley, Hillington, Glasgow, Scotland, assignors to llford Limited, Ilford, England, a British company No Drawing. Filed Aug. 14, .1959, Ser. No. 833,671 9 Claims. (Cl. 96-60) The present invention concerns chemical solutions for use in the development and processing of exposed photographic film in continuously operating rapid processing photographic projectors in which continuous 24-hour operation is a factor of considerable importance.
This application is a continuation-in-part of application Serial No. 752,928, filed August 4, 1958.
It is an object of the invention to provide means in photographic developer and bleach solutions to reduce or eliminate the formation of precipitants in rapid photographic processing which build up and block fluid fiow through jet sprays having small orifices.
Rapid processing photographic projectors of the kind here concerned can develop and project a photograph in as short a time as two seconds. Where better resolution and archival quality are required, black and white processing requires from four to six seconds and colour processing presently requires about fifteen seconds.
The physical structures of rapid processing photographic projectors intended for continuous operation with which the present invention is intended to be used are disclosed in co-pending application Serial No. 642,698, titled Processing of Photographic Material, filed February 27, 1957. Reference is also made to a brochure published by Kelvin & Hughes Limited, New North Road, Barkingside, Essex, England, entitled: Rapid Processing Photographic Projector.
In the aforesaid apparatus the exposed photographic material is subjected to successive processing solutions whereby a positive image is formed in the material and the material is immediately passed through an optical projection section whereby the projected positive image may be viewed. To arrive at a positive image it is necessary that the processing should be by the so-called reversal method, is. the initial latent image resultant on light exposure is developed to a negative record in silver; this silver is bleached out and the residual silver halide is developed. Moreover, where a colour image is to be obtained it is necessary to bleach out the developed silver (existing either as negative or positive image).
The processing solutions are applied by means of jet applications operating in a single processing zone. This leads to some problems. The developers used are normally highly alkaline and the most eifective silver bleach baths are those based on chromic acid. Hence, after the first jet has sprayed developer the walls of the processing zone and the surfaces of the jet unit become contaminated with highly alkaline developer which, when followed by the use of the chromic acid bleach solution, slowly results in a buildup of a complex chromium hydroxide sludge which has been found to cause severe blockage of the jets themselves and interfere with the quality of the processing due to its formation on the interior surfaces of the processing zone. In some cases the machine ceases to function.
This problem is not normally encountered with conventional dish processing since the photographic emulsion is usua'lly developed, thoroughly washed and subsequently placed in a separate bath of bleach solution and thus developer and the acid bleach.
Normally, it is necessary to utilise an oxidising acid such as the chromic acid previously mentioned in order successfully to dissolve the silver image in a short period of time. This oxidising acid usually consists of a mixture of sulphuric acid and potassium dichromate in various proportions which gives a complex oxidising acid containing chromic acids, dichromic acids, etc. The precise mechanism of this chemical reaction is not agreed to by all the various authorities.
It will be readily seen that in developer solution containing a large amount of hydroxyl ions, caustic soda will react with the chromium salts and form various complex chromium hydroxides, and it is these compounds which cause trouble, slowly but inevitably, as a result of the successive application of each processing cycle, although only a minute amount of precipitation is caused on each occasion. In practice, it is found that the equipment will work satisfactorily for a few days and after this the successful operation is very much interfered with or interrupted by the deposited sludge described above.
In order to solve this problem we investigated the working of the solution and found that if an addition of acetic acid is made to the solution, this sludge formation can be so much minimised as to make the operation of the equipment in the same way hitherto described completely successful. A small mount of sludge is still formed under these conditions, but the amount is negligible and appears not to matter.
According to the present invention, therefore, there is provided a bleach solution for use in rapid processing photographic projectors in which the elapsed time from exposure to projection is less than thirty seconds, consisting of potassium dichromate, acetic acid, and sulphuric acid so proportioned that photographic film is rapidly processed with the production of a negligible amount of sludge and the elimination of staining in the event of over-bleaching.
Preferably the bleach solution characteristic of this invention contains, in aqueous solution, 0.5 to 5% by weight potassium dichromate, 0.5 to 10% by weight acetic acid and 2 to 15% by weight sulphuric acid. Where the processing time is 2 to 6 seconds it is preferred that the solution should contain less than 2% potassium dichromate, lessthan 4% acetic acid, and less than 6% sulphuric acid.
In particular there may be used an aqueous solution comprising:
Percent by weight Various changes in the constitution of each of these substances are permissible over the range indicated and still give satisfactory results. However, the particular solution just set forth is probably optimum for vuse in the above'equipment as it also provides the correct bleaching time and avoids most of the staining difficulties associated with such solution when the film emulsion is over-bleached.
It is believed that the addition of acetic acid to the chromic acid solution as outlined above makes all the difference between success and failure in the continuous operation of rapid processing photographic projectors of the type under consideration.
The following example will serve to illustrate the invention:
EXAMPLE Photographic colour film comprising a silver halide emulsion containing a coupling compound which, on de- Jet 1.Develper Hexamethylene phosphate (the commercial product Calgon (in 20% solution) mls 15 Trisodium phosphate (cryst.) g 80 Sodium sulphite anhydrous in aqueous solution) mls 50 Potassium bromide (10% aqueous solution) rnls l0 Diethylaminotoluidine g 4 1-phenyl-3-pyrazolidone (0.625 g. +6 ml. of 10% anhydrous sodium sulphite in water, made up to 100 cc. with water) mls 10 Water to make, 1 litre.
Jet 2.Bleaching Solution Potassium dichromate (cryst.) g 10 Sulphuric acid (conc.) g 20 Glacial acetic acid g 50 Water to make, 1 litre.
Jet 3.Fixing Solution Ammonium thiocyanate (cryst.) Dye (Soluble Blue N) Water to make, 1 litre.
Jet 4.-Wash Solution 2% aqueous sodium thiosulphate (cryst.)
The aforesaid type of material yields images in colour on a white background.
While there have been described above what are presently believed to be the preferred forms of the invention, variations thereof will be obvious to those skilled in the art and all such changes and variations which fall within the spirit of the invention are intended to be covered by the generic terms in the appended claims, which are variably worded to that end.
What we claim is:
1. A bleach solution for use in rapid processing photographic projectors in which the elapsed time from exposure to projection is less than thirty seconds, consisting of potassium dichromate, acetic acid, sulphuric acid and water so proportioned that photographic film is rapidly processed with the production of a negligible amount of sludge and the elimination of staining in the event of over-bleaching, the percentage of potassium dichromate being at least half a percent and not more than five percent by weight, of anhydrous acetic acid being at least half a percent and not more than ten percent by weight, of anhydrous sulphuric acid being at least two percent and not more than fifteen percent by weight, and the balance being water to make up one hundred percent.
2. A bleach solution for use in rapid processing photographic projectors in which the elapsed time from exposure to projection is less than thirty seconds, consisting of potassium dichromate, acetic acid, sulphuric acid and water so proportioned that photographic film is rapidly processed with the production of a negligible amount of sludge and the elimination of staining in the event of over-bleaching, the percentage of potassium dichromate being not more than two percent by weight, of anhydrous acetic acid being not more than four percent by weight, of anhydrous sulphuric acid being not more than six percent by weight and of water being at least eight-eight percent by weight whereby the processing time of said bleach solution is between two and six seconds.
3. In a process for the rapid processing of photographic materials enroute from an exposure position to a projection position with a time lapse of less than thirty seconds from exposure to projection, the step of bleaching a developed silver image by treating the photographic material with a bleach solution consisting of potassium dichromate, acetic acid, sulphuric acid and water in which the percentage of potassium dichromate is at least half a percent and not more than five percent by weight, anhydrous acetic acid is at least half a percent and not more than ten percent by weight, anhydrous sulphuric acid is at least two percent and not more than fifteen percent by weight, and the balance is water to make up one hundred percent.
4. The process set forth in claim 3, in which the percentage of potassium dichromate is not more than two percent by weight, of anhydrous acetic acid is not more than four percent by weight, of anhydrous sulphuric acid is not more than six percent by weight and of water at least eighty-eight percent by weight whereby the processing time of said bleach solution is between two and six seconds.
5. The process set forth in claim 4, in which the percentage of potassium dichromate is substantially one percent by weight, of anhydrous acetic acid substantially two percent by weight, of anhydrous sulphuric acid substantia'lly three percent by weight, and water substantially ninety-four percent by weight whereby the elapsed time from exposure to projection is less than thirty seconds.
6. In a process for the rapid processing of photographic materials the steps of exposing the photographic material, developing a silver image by treating the photographic material with a developer solution, bleaching the developed silver image by treating the photographic material with a bleach solution consisting of potassium dichromate, acetic acid, sulphuric acid and water in which the percentage of potassium dichromate is at least half a percent and not more than five percent by weight, anhydrous acetic acid is at least half a percent and not more than ten percent by weight, anhydrous sulphuric acid is at least two percent and not more than fifteen percent by weight, and the balance is water to make up one hundred percent, washing the photographic materials with a wash solution and drying the photographic materials, all with a time lapse of less than twenty seconds.
7. The process set forth in claim 6, in which the percentage of potassium dichromate is not more than two percent by weight, of anhydrous acetic acid is not more than four percent by weight, of anhydrous sulphuric acid is not more than six percent by weight and of water at least eighty-eight percent by weight whereby the processing time of said bleach solution is between two and six seconds.
8. The process set forth in claim 7, in which the percentage of potassium is substantially one percent by weight, of anhydrous acetic acid substantially two percent by weight, of anhydrous sulphuric acid substantially three percent by weight and water substantially ninetyfour percent by weight whereby the elapsed time from exposure to projection is less than thirty seconds.
9. The process set forth in claim 8, and the step of projecting the dried photographic material all with a time lapse of less than twenty seconds.
References Cited in the file of this patent UNITED STATES PATENTS 1,930,140 Becker Oct. 10, 1933 2,195,419 McQueen et al. Apr. 2, 1940 2,326,055 Morris Aug. 3, 1943 2,507,183 Wilder et al. May 9, 1950 OTHER REFERENCES American Photographic Publishing (30., Boston (1947).
Claims (1)
- 3. IN A PROCESS FOR THE RAPID PROCESSING OF PHOTOGRAPHIC MATERIALS ENROUTE FROM AN EXPOSURE POSITION TO A PROJECTION POSITION WITH A TIME LAPSE OF LESS THAN THIRTY SECONDS FROM EXPOSURE TO PROJECTION, THE STEP OF BLEACHING A DEVELOPED SILVER IMAGE BY TREATING THE PHOTOGRAPHIC MATERIAL WITH A BLEACH SOLUTION CONSISTING OF POTASSIUM DICHROMATE, ACETIC ACID, SULPHURIC ACID AND WATER IN WHICH THE PERCENTAGE OF POTASSIUM DICHROMATE IS AT LEAST HALF A PERCENT AND NOT MORE THAN FIVE PERCENT BY WEIGHT, ANHYDROUS ACETIC ACID IS AT LEAST HALF A PERCENT AND NOT MORE THAN TEN PERCENT BY WEIGHT, ANHYDROUS SULPHURIC ACID IS AT LEAST TWO PERCENT AND NOT MORE THAN FIFTEEN PERCENT BY WEIGHT, AND THE BALANCE IS WATER TO MAKE UP ONE HUNDRED PERCENT.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US833671A US3061433A (en) | 1958-08-04 | 1959-08-14 | Process and solution for bleaching photographic images |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US752928A US3006260A (en) | 1957-08-09 | 1958-08-04 | Production of photographic colour records |
US833671A US3061433A (en) | 1958-08-04 | 1959-08-14 | Process and solution for bleaching photographic images |
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US3061433A true US3061433A (en) | 1962-10-30 |
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US833671A Expired - Lifetime US3061433A (en) | 1958-08-04 | 1959-08-14 | Process and solution for bleaching photographic images |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5616453A (en) * | 1994-08-30 | 1997-04-01 | Konica Corporation | Silver halide light-sensitive color photographic material |
US5716767A (en) * | 1995-12-29 | 1998-02-10 | Agfa-Gevaert Ag | Bleaching bath for photographic black-&-white material |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1930140A (en) * | 1932-01-23 | 1933-10-10 | Eastman Kodak Co | Acid hardening fixing bath |
US2195419A (en) * | 1938-10-03 | 1940-04-02 | Du Pont Film Mfg Corp | Process for reducing the density of silver images and compositions therefor |
US2326055A (en) * | 1940-10-10 | 1943-08-03 | Eastman Kodak Co | Dye bleaching process |
US2507183A (en) * | 1945-03-23 | 1950-05-09 | Eastman Kodak Co | Silver bleach for color materials |
-
1959
- 1959-08-14 US US833671A patent/US3061433A/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1930140A (en) * | 1932-01-23 | 1933-10-10 | Eastman Kodak Co | Acid hardening fixing bath |
US2195419A (en) * | 1938-10-03 | 1940-04-02 | Du Pont Film Mfg Corp | Process for reducing the density of silver images and compositions therefor |
US2326055A (en) * | 1940-10-10 | 1943-08-03 | Eastman Kodak Co | Dye bleaching process |
US2507183A (en) * | 1945-03-23 | 1950-05-09 | Eastman Kodak Co | Silver bleach for color materials |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5616453A (en) * | 1994-08-30 | 1997-04-01 | Konica Corporation | Silver halide light-sensitive color photographic material |
US5716767A (en) * | 1995-12-29 | 1998-02-10 | Agfa-Gevaert Ag | Bleaching bath for photographic black-&-white material |
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