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AssigneeMinnesota Mining and Manufacturing Company
InventorCarlo Marchesano
Estimating the term…
Developer for use in color photography confectioned in a plurality of concentrated compositions in which one first concentrated composition is a liquid composition substantially free of water including the p-phenylenediamine compound, and possibly other components of the developer such as antioxidants, dissolved in an organic solvent.
A concentrated color photographic developer solution to be mixed with an alkaline aqueous composition characterized by the fact that said concentrated solution is a liquid composition having no more than 5% volume of the total volume of said concentrated composition as water and includes 5 to 50 g per 100 ml of said solution of a p-phenylene-diamine compound dissolved in a photographically neutral organic solvent which is miscible with water.
Dependencies are inferred from the claim text.
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Supplying of photographic processing chemicals; Preparation or packaging thereof: of solutions or concentrates
Photosensitive materials for photographic purposes
Term ended 14 Mar 1999 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention refers to liquid concentrated developer compositions for use in colour photography. Particularly, the present invention refers to liquid concentrated developers which are confectioned into more concentrated parts to dilute with water to give colour developer baths ready to use in colour photography.
Generally, a developer solution for use in colour photography, consists of a water solution of various components in addition to the p-phenylenediamine developer which is oxidized by the exposed silver halide to react with a coupler to form a dye.
Such components normally include an antioxidant(s) and an alkalizing agent(s) and various additional compounds such as a buffering agent(s), an anticalcium agent(s) (see for example U.S. Pat. Nos. 2,656,273, 3,462,269, 3,201,246, 3,214,654, 3,994,730, FR Pat. No. 2,251,036 and Research Disclosure No. 13410, 1975), an optical brightner (s) (as for example described in Research 17643-V, 1978), as well as other known development modifiers such as for example described in the above cited Research Disclosure 17643(1978) with particular reference to paragraph XXI. Particular mention as to crytical components is to be made to said antioxidant compounds and to benzylalcohol which is normally used, as development accelerator, in developers for Color Paper films (as described for example in U.S. Pat. No. 2,304,925).
The invention is now described with reference to some experiments made by the Applicant.
The developer components for color photographic paper were confectioned in the following concentrated liquid compositions necessary to prepare one liter of developer replenisher ready for use:
Composition A