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
  • G03C8/00—Diffusion transfer processes or agents therefor; Photosensitive materials for such processes
  • G03C8/02—Photosensitive materials characterised by the image-forming section
  • G03C8/04—Photosensitive materials characterised by the image-forming section the substances transferred by diffusion consisting of inorganic or organo-metallic compounds derived from photosensitive noble metals
  • G03C8/06—Silver salt diffusion transfer

Definitions

• the two layers may both be mounted on one support and are separated after the diffusion and development.
• a two-layer material is used, the lower layer being hardened, while the top-layer having a very low meltingpoint is removed after complete diffusion by means of warm water. This warm water treatment must be carried out in the darkroom which is rather inconvenient.
• This object is accomplished by the simple means of adding to the diffusion bath a substance which in solution is a solvent for gelatine.
• the difiusion of the silver halide and the removal of the emulsion layer are performed in a bath which contains gelatine solvents such as thiocyanates or organic sulphonic acids, which are used in the gelatine industry, e. g. for keeping glue fluid (Ullmann Encyclopaedia, Bd. 5, p. 599).
• gelatine solvents such as thiocyanates or organic sulphonic acids
• glue fluid Ullmann Encyclopaedia, Bd. 5, p. 599.
• similar salts e. g. ammonium carbonate
• the method offers many advantages: While the process described in my prior patent and patent application mentioned above requires four treating-baths, viz. a developing bath, a, diffusion-bath, a warm-water bath, and a toning-bath, the new process according to this invention dispenses with the highly undesirable manipulation with warm water in the dark-room. The ensuing shortening of the processing time is particularly valuable for a quick determination of the exact time required for exposure (proofexposure).
• the difiusion is stopped automatically, so that the time required for the diffusion of different images becomes uniform, and consequently more uniform images are obtained. It also renders unnecessary a time control of the manipulation in the diffusion-bath (such as may be required for a fixing bath). This is of particular commercial importance for the output per unit of time when producing a large number of images.
• Substances which restrain the diffusion of bleaching and other liquors, into the photographic emulsion, as described e. g. in Patent 2,059,884, may also be added to the difiusion and dissolving bath whereby to restrain its diffusion and to reduce the image-gradation.
• the diffusion and dissolving bath is soiled by the dissolved gelatine. This drawback although as a rule not affecting the final result may be avoided by so compounding the bath that the gelatine layer is not washed away but is only affected to such an extent that it can be washed away subsequently with cold water or can be removed in cold water by light rubbing.
• I may add substances containing an ionizable OH group, for instance as described in Patent Number 2,366, i96, which prevent crystallization from occurring such as for instance an alkali metal hydroxide or other bases such as hydrocarbon substituted ammonium hydroxides or sulfonium hydroxides.
• Example 1 Water 1000 cm. Metol 1.5 g. Sodium sulphite (cryst) 50 g. or anhydrous 25 g. Hydroquinone 6 g. Sodium carbonate (cryst. g. or anhydrous 40 g.
• the developed product is treated in a bath of the following composition:
• the exposed material is developed 1 minute in The developed product is treated 2 minutes in a bath which is composed as follows:
• Solution B is prepared by heating until complete solution and by filtration. For use, 50 cm. of solution B are added to 1000 cm. of solution A. After treatment in the bath, the emulsion layer is dissolved and a positive black-brown text image is obtained, which need not be treated further.
• Example 3 On a material, consisting of (a) a support, (0) a hardened light-sensitive emulsion layer, which contains reduction nuclei, (0) an unhardened light-sensitive emulsion layer, a drawing is reproduced by contact, for example, a design for textile printing. The exposed material is developed for 4 minutes in a developer of the following composition:
• the developed product is treated 5 minutes in a bath composed as follows:
• gelatine solvent is potassium thiocyanate- 3.
• gelatinte solvent is alpha naphthalene sodium sulfona e.
• gelatine solvent solution also contains a crystallisationpreventing substance containing an ionizable Oil-group in its molecule.

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• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

Applications Claiming Priority (1)

Publications (1)

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Cited By (3)

Citations (15)

• 0
  • NL NL60845D patent/NL60845C/xx active
  • BE BE476512D patent/BE476512A/xx unknown
  • NL NL128013D patent/NL128013B/xx unknown
• 1947
  • 1947-09-30 US US777105A patent/US2663641A/en not_active Expired - Lifetime
  • 1947-10-02 GB GB26570/47A patent/GB665984A/en not_active Expired
  • 1947-10-07 FR FR57717D patent/FR57717E/fr not_active Expired

Patent Citations (15)

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