GB769421A - Improvements in and relating to the production of photographic images - Google Patents
Improvements in and relating to the production of photographic imagesInfo
- Publication number
- GB769421A GB769421A GB117953A GB117953A GB769421A GB 769421 A GB769421 A GB 769421A GB 117953 A GB117953 A GB 117953A GB 117953 A GB117953 A GB 117953A GB 769421 A GB769421 A GB 769421A
- Authority
- GB
- United Kingdom
- Prior art keywords
- silver
- alkali
- photographic
- per litre
- jan
- 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
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
- 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
- G03C5/46—Toning
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Paper (AREA)
- Silver Salt Photography Or Processing Solution Therefor (AREA)
Abstract
769,421. Photographic processes. HARDMAN & HOLDEN, Ltd., and WAKEFIELD, G. L. Jan. 14, 1954 [Jan, 15, 1953], No. 1179/53. Drawings to Specification. Class 98(2). Photographic silver images are treated by bleaching them to a silver salt image and then reducing this with thiourea dioxide or an alkyl derivative thereof at a pH greater than 7, whereby, according to conditions, the images are toned or the reflection density of the maximum black is increased. The silver image may be oxidized to silver bromide with an aqueous potassium bromide/ferricyanide solution or the silver salt image may be the ferrocyanide. The reducing solution preferably contains from “ per cent to 2¢ per cent by weight of thiourea dioxide and from 1 to 30 grammes per litre of alkali. To effect toning, the alkali is preferably sodium carbonate, but sodium or potassium hydroxide may be used in an amount of less than 15 g. per litre. The temperature of the reducing solution may be between 65 and 120‹F., and by varying this and the concentrations of the components a wide variety of tones can be produced. By using solutions containing at least 15 g. per litre of caustic alkali the reflection density of the maximum black obtainable on a photographic paper is increased.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB117953A GB769421A (en) | 1953-01-15 | 1953-01-15 | Improvements in and relating to the production of photographic images |
| DEW13028A DE942777C (en) | 1953-01-15 | 1954-01-16 | Process for the production of colored or enhanced black silver images |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB117953A GB769421A (en) | 1953-01-15 | 1953-01-15 | Improvements in and relating to the production of photographic images |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB769421A true GB769421A (en) | 1957-03-06 |
Family
ID=9717530
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB117953A Expired GB769421A (en) | 1953-01-15 | 1953-01-15 | Improvements in and relating to the production of photographic images |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE942777C (en) |
| GB (1) | GB769421A (en) |
-
1953
- 1953-01-15 GB GB117953A patent/GB769421A/en not_active Expired
-
1954
- 1954-01-16 DE DEW13028A patent/DE942777C/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE942777C (en) | 1956-05-09 |
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