US2453323A - Photographic development by ferrous alkaline solutions - Google Patents
Photographic development by ferrous alkaline solutions Download PDFInfo
- Publication number
- US2453323A US2453323A US706073A US70607346A US2453323A US 2453323 A US2453323 A US 2453323A US 706073 A US706073 A US 706073A US 70607346 A US70607346 A US 70607346A US 2453323 A US2453323 A US 2453323A
- Authority
- US
- United States
- Prior art keywords
- ferrous
- oxalate
- solution
- development
- silver halide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
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
- 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
- G03C7/407—Development processes or agents therefor
- G03C7/413—Developers
Definitions
- This invention relates to photography and particularly to photographic development by alkaline ferrous iron solutions.
- ferrous salts such as ferrous oxalate
- ferrous oxalate and other ferrous salts have been used in acid solution to develop silver halide emulsions by reducing the exposed silver halide to metallic silver. Such solutions have been used only in the acid or neutral state.
- exposed silver halide may be developed with a solution of a ferrous salt of suitable alkalinity and that such development produces a ferric oxide image along with the metallic silver image. The silver may then be removed leaving the ferric oxide image in the developer layer.
- the solution which I propose to use for development of an exposed silver halide emulsion layer preferably consists of suitable concentrations of ferrous sulfate and potassium oxalate in a solution made alkaline with borax or other alkali to a pH of about 8 or more.
- Any soluble ferrous salt not involving a complex ion may be employed such as ferrous sulfate or ferrous chloride.
- Any soluble oxalate such as sodium oxalate or potassium oxalate is suitable. While the function of the oxalate is not entirely clear, I believe that without the oxalate, ferrous hydroxide is formed in solution and this does not penetrate the emulsion layer sufficiently to achieve satisfactory development.
- ferro-oxalate ions may be produced in the alkaline solutions containing low or moderate concentrations of oxalate ions, it is unlikely that the ferro-oxalate ion is the principal developer in such alkaline solution.
- the alkaline ferrous solutions therefore differ from the conventional acid ferro-oxalate developers in which the ferro-oxalate ion is the active developer.
- the developing solution may also contain a small amount of restrainer such as potassium bromide as well as other agents used in developers of this type.
- the pH of the developer is an important factor in my method.
- the pH should be above about 8 and as the pI-I increases, additional amounts of oxalate should be used in the solution to prevent premature formation of ferrous hydroxide.
- pH 8.8 good images were obtained at concentraticns of potassium oxalate of from 10 grams to 100 grams per liter of developing solution.
- Ferric oxide images of good quality were obtained when development was carried out in suitable solutions which had been freed from oxygen and maintained under an atmosphere of oxygen-free nitrogen during development.
- Weaker images were obtained by development in solutions made up without precautions to exclude oxygen and used in air.
- Borax to produce pH of about 8.8. Water to 1 liter.
- the silver image produced by development may be removed with the usual ferrocyanide-hypo bleach.
- the ferric oxide images produced according to my invention are useful in a number of ways. They may be converted into a ferric ferroci anide image or used as a mordant for various anthraquinone and acid mordant dyes. They may also be used for the production of dyes of the naphthol green B type by reaction of the ferric oxide with dinitro-resorcinol, a-nitroso-o-naphthol, etc., or for the production of black images by treatment wth tannin or logwood. If the silver image is allowed to remain in the emulsion layer, the ferric oxide may be used in combination with the silver image, for sepia toned prints.
- the method of forming a ferric oxide image in a silver halide emulsion layer which comprises exposing said layer and developing it with an alkaline solution of a soluble ferrous salt and a soluble oxalate in an oxygen free atmosphere, said solution having a pH of at least approximately 8.
- the method of forming a ferric oxide image in a silver halide emulsion layer which comprises exposing said layer and developing it with an alkaline solution of a soluble ferrous salt and a soluble oxalate in an oxygen free atmosphere, said solution having a pH of at least approximately 8, and removing the developedsilver and unexposed silver halide from the layer.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Silver Salt Photography Or Processing Solution Therefor (AREA)
Description
Patented Nov. 9, 1948 PHOTOGRAPHIC DEVELOPMENT BY FERROUS ALKALINE SOLUTIONS Thomas H. James, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application October 26, 1946, Serial No. 106,073
1 5 Claims. 1
This invention relates to photography and particularly to photographic development by alkaline ferrous iron solutions.
The development of exposed silver halide emulsions with ferrous salts such as ferrous oxalate is well known. Ferrous oxalate and other ferrous salts have been used in acid solution to develop silver halide emulsions by reducing the exposed silver halide to metallic silver. Such solutions have been used only in the acid or neutral state.
I have found that exposed silver halide may be developed with a solution of a ferrous salt of suitable alkalinity and that such development produces a ferric oxide image along with the metallic silver image. The silver may then be removed leaving the ferric oxide image in the developer layer.
The solution which I propose to use for development of an exposed silver halide emulsion layer preferably consists of suitable concentrations of ferrous sulfate and potassium oxalate in a solution made alkaline with borax or other alkali to a pH of about 8 or more. Any soluble ferrous salt not involving a complex ion may be employed such as ferrous sulfate or ferrous chloride. Any soluble oxalate such as sodium oxalate or potassium oxalate is suitable. While the function of the oxalate is not entirely clear, I believe that without the oxalate, ferrous hydroxide is formed in solution and this does not penetrate the emulsion layer sufficiently to achieve satisfactory development. While ferro-oxalate ions may be produced in the alkaline solutions containing low or moderate concentrations of oxalate ions, it is unlikely that the ferro-oxalate ion is the principal developer in such alkaline solution. The alkaline ferrous solutions therefore differ from the conventional acid ferro-oxalate developers in which the ferro-oxalate ion is the active developer.
The developing solution may also contain a small amount of restrainer such as potassium bromide as well as other agents used in developers of this type.
The pH of the developer is an important factor in my method. The pH should be above about 8 and as the pI-I increases, additional amounts of oxalate should be used in the solution to prevent premature formation of ferrous hydroxide. At pH 8.8 good images were obtained at concentraticns of potassium oxalate of from 10 grams to 100 grams per liter of developing solution.
It is preferable in my process to carry out the development in an atmosphere free of oxygen.
Ferric oxide images of good quality were obtained when development was carried out in suitable solutions which had been freed from oxygen and maintained under an atmosphere of oxygen-free nitrogen during development. Weaker images were obtained by development in solutions made up without precautions to exclude oxygen and used in air.
The following solution is suitable for development of an exposed silver halide emulsion according to my invention:
Grams FeSO4.7I-I2O 2.78
I. 2C2OA..H2O 37.0
Potassium bromide 0.4
Borax to produce pH of about 8.8. Water to 1 liter.
The silver image produced by development may be removed with the usual ferrocyanide-hypo bleach.
The ferric oxide images produced according to my invention are useful in a number of ways. They may be converted into a ferric ferroci anide image or used as a mordant for various anthraquinone and acid mordant dyes. They may also be used for the production of dyes of the naphthol green B type by reaction of the ferric oxide with dinitro-resorcinol, a-nitroso-o-naphthol, etc., or for the production of black images by treatment wth tannin or logwood. If the silver image is allowed to remain in the emulsion layer, the ferric oxide may be used in combination with the silver image, for sepia toned prints.
It will be understood that my invention is to be taken as limited only by the scope of the appended claims.
I claim:
1. The method of forming a ferric oxide image in a silver halide emulsion layer, which comprises exposing said layer and developing it with an alkaline solution of a soluble ferrous salt and a soluble oxalate in an oxygen free atmosphere, said solution having a pH of at least approximately 8.
2. The method of forming a ferric oxide image in a silver halide emulsion layer, which comprises exposing said layer and developing it with an alkaline solution of a soluble ferrous salt and a soluble oxalate in an oxygen free atmosphere, said solution having a pH of at least approximately 8, and removing the developedsilver and unexposed silver halide from the layer.
3. The method of forming a ferric oxide image in a silver halide' -emulsion layer which comprises exposing said layer and developing it with an alkaline solution of ferrous sulfate and potassium oxalate in an oxygen-free atmosphere, said solution having a pH of at least approximately 8.
4. Themethod v,ofiorming aierriotoxide image in a. silver halide .ilayer which comprises exposing said layer and developing it with an alkaline solution containing ferrous sulfate and from 10 grams to .100 grams per liter of potassium oxalate in an oxygen-free atmosphere, 'sa'idsolution having a pH of approximately 8.8.
5. The method of forming a ferric oxide image in a silver halide layer which room-prises exposing said layer and developing it with an alkaline solution containing ferrous sulfate and from 10 grams to 100 grams per liter of potassium oxalate in an' oxygen-free atmosphere, said solution having 'a pH of approximately 8.8, and removing the developed silver and unexposed silver halide from the layer.
THOMAS H. JAMES.
REFERENCES 'GITZE'D The following references are of record in the ..file of this patent:
UNIT-ED STATES PATENTS 'XXVII, 'l'880ypages 2'79 and 280 cited.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US706073A US2453323A (en) | 1946-10-26 | 1946-10-26 | Photographic development by ferrous alkaline solutions |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US706073A US2453323A (en) | 1946-10-26 | 1946-10-26 | Photographic development by ferrous alkaline solutions |
Publications (1)
Publication Number | Publication Date |
---|---|
US2453323A true US2453323A (en) | 1948-11-09 |
Family
ID=24836116
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US706073A Expired - Lifetime US2453323A (en) | 1946-10-26 | 1946-10-26 | Photographic development by ferrous alkaline solutions |
Country Status (1)
Country | Link |
---|---|
US (1) | US2453323A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2563669A (en) * | 1941-11-21 | 1951-08-07 | Ahearn John Carrington | Concrete mixer |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1055155A (en) * | 1912-07-01 | 1913-03-04 | Rudolf Fischer | Process of making photographs in natural colors. |
-
1946
- 1946-10-26 US US706073A patent/US2453323A/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1055155A (en) * | 1912-07-01 | 1913-03-04 | Rudolf Fischer | Process of making photographs in natural colors. |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2563669A (en) * | 1941-11-21 | 1951-08-07 | Ahearn John Carrington | Concrete mixer |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP3045311B2 (en) | Photo color processing method | |
US3770437A (en) | Photographic bleach compositions | |
US3042520A (en) | Bleaching bath for processing color film | |
US3293036A (en) | Bleach-fix compositions and process for producing colored photographic images | |
US2453323A (en) | Photographic development by ferrous alkaline solutions | |
US4040837A (en) | Photographic bleach-fixer | |
US3702247A (en) | Color photographic process using a bleach-fix solution containing a selenosulfate | |
JPH051456B2 (en) | ||
JPH06503893A (en) | photo bleaching composition | |
US2013116A (en) | Photographic matrix | |
US2171609A (en) | Toning photographic prints | |
US2706687A (en) | Preventing formation of prussian blue stain in color developed photographic prints | |
US3942984A (en) | Process for bleach-fixing chromogenically color photographic silver halide material | |
US2341079A (en) | Color photography | |
US4113489A (en) | Method of forming photographic line and half-tone images | |
US3352676A (en) | Processing of color photographic materials | |
US3161514A (en) | Nonstaining photographic developers | |
US2231201A (en) | Toning photographic prints | |
US3664838A (en) | Treatment of and developing composition for photographic light-sensitive materials | |
US2218001A (en) | Process for making colored prints | |
US2093421A (en) | Method of making photoprints and developer therefor | |
US3667952A (en) | Color stabilization processing | |
US2419900A (en) | Bleaching bath and process for bleaching color film | |
US1453258A (en) | Process of making a contact transfer printing surface with a colored emulsion | |
US1600797A (en) | Asfllokob to babjkicav kodak ook |