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
  • G03C5/264—Supplying of photographic processing chemicals; Preparation or packaging thereof
  • G03C5/265—Supplying of photographic processing chemicals; Preparation or packaging thereof of powders, granulates, tablets

Definitions

• This invention relates to single-powder photographicdevelopers, and more particularly to a single-powder developer in which the ingredients of the developer are intimately mixed in the form of dry powder with powdered metaboric acid (H302), as a stabilizing agent to prevent disadvantageous interaction between the or anic developer component and the basic component ofthe single-powder mixture.
• powdered metaboric acid H302
• the alkali component may be the stable hydrate of an alkali carbonate, a desiccated alkali carbonate, an alkali metaborate, or an alkali sulfite. Generally the stable alkali carbonate monohydrate is preferred.
• the oxidation preventing compound may be potassium bromide or iodide. Stabilizing components for such a single-powder developer are disclosed in Patent 2,384,592, of September 11, 1945, and include maleic anhydride, salicyclic acid, al-
• an improved stabilizing agent which makes possible the production of single-powder developers having improved stabilizing characteristics containing as the alkali ingredient, sodium metaborate.
• metaboric acid does not have the objectionable characteristics possessed by phthalic anhydride. Because metaboric acid is less acid than phthalic anhydride it does not react as easily or as violently as phthalic anhydride with alkali carbonates or alkali sulfites such as sodium carbonate and sodium sulfite. In this respect it is noted that the pH of phthalic anhydride is about 2.4 while the pH of metaboric acid is about 5.4 at 3% concentrations. 'Metaboric acid is especially suited as a stabilizer and has characteristics required for a stabilizer. It
• a preferred embodiment of the present inven-' tion involves the use in the single-powder photographic developer mixture of either the stable hydrate of an alkali carbonate or also a desiccated alkali carbonate.
• the alkali carbonate hydrate appears to be more stable in the presence of an organic developer than a comparable quan-,
• a stable alkali carbonate such as sodium carbonate monohydrate
• metaboric acid may contain the other well known ingredients normally present in a developer, such as sodium sulfite and potassium bromide, the normal and known function of the alkali sulfite being that of preservative, lessening the oxidation in solution of the organic developing agent; while the known function of potassium bromide is that of a restrainer particularly inhibiting fog formation in the development of the silver image.
• sodium metaborate is employed its moisture content should be not more than 35% and preferably be about
• one may proceed by first mixing th stabilizer and the basic component, adding and mixing therewith the developing agent, which is followed by incorporating the other ingredients. However, one can mix all the ingredients together at the same time without causing any diiliculty.
• Example 8 Grains Sodium sulfite 50 Sodium carbonate monohydrate 54 Potassium bromide 1 Metaboric acid 2.2 p-Aminophenol sulfate 7.3
• Example 10 Grams Sodium sulfite 75 Sodium carbonate monohydrate 30 Potassium iodide .01 Metaboric acid 2.2 Hydroquinone 9 Elon 1
• Example 11 Grams Elon 10.0 Anhydrous sodium sulfite. 1 100.0 Sodium metaborate 20.0 Metaboric acid 4.0
• a stable single-powder photographic developer composition containing an organic silver halide developer, a stabilizing agent comprising metaboric acid and a soluble, stable, and photographically compatible basic ingredient selected from the group consisting of alkali borates, sulfites and carbonates.
• a stable single-powder photographic developer composition containing an organic silver halide developer, a stabilizing agent comprising metaboric acid, an antifoggant, and a soluble, stable, and photographically compatible basic ingredient selected from the group consisting of alkali borates, sulfites and carbonates.
• a stable single-powder photographic developer composition containing an organic silver halide developer, sodium carbonate monohydrate;
• a stable single-powder photographic developer containing an organic silver halide developer, an anhydrous alkali carbonate, an alkali sulfite and metaboric acid.
• a stable single-powder photographic developer composition containing an organic silver halide developer, sodium sulfite, sodium metaborate, and metaboric acid.

Landscapes

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

Priority Applications (4)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23139409

Family Applications (1)

Country Status (4)

Cited By (1)

Citations (1)

• 0
  • BE BE520998D patent/BE520998A/xx unknown
• 1952
  • 1952-06-26 US US295834A patent/US2666703A/en not_active Expired - Lifetime
• 1953
  • 1953-06-26 GB GB17744/53A patent/GB729388A/en not_active Expired
  • 1953-06-26 FR FR1079629D patent/FR1079629A/fr not_active Expired

Patent Citations (1)

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