Eastman-kodak Company

Michael D Purol

Paul A Zielinski

Donald L Kerr

Sheridan E Vincent

Richard R Horn

Susan R Krauss

Christine K Gaskell

A method of treating photoprocessing wash water, comprising in sequence, the steps of: A) contacting the wash water with an acrylic anion exchange resin to remove silver thiosulfate complex in the water; and B) contacting the water from step A) with an oxidizing agent that converts thiosulfate ions to sulfate ions. C) recirculating continuously through the photoprocessing wash tank and steps A) and B).

Process for recycling photographic wash water

An improved photographic developing solution is free of dihydroxybenzene developing agents such as hydroquinone, has a pH in the range of from 9.5 to 11.5 and comprises (1) an ascorbic acid developing agent, (2) an auxiliary super-additive developing agent and (3) a carbonate buffering agent in a concentration of at least 0.5 molar. The developing solution is broadly useful in black-and-white development but is most advantageously employed in a process for forming a high-contrast image utilizing a silver halide photographic element comprising a hydrazine compound which functions as a nucleating agent and an amino compound which functions as an incorporated booster. The developing solution is ecologically advantageous, exhibits excellent stability with respect to seasoning effects, and provides high speed and good upper scale contrast combined with a low level of pepper fog and a moderate degree of chemical spread.

Photographic developing solution and use thereof in the high contrast

Photographic color developer compositions containing a primary aromatic amino color developing agent and an hydroxylamine are stabilized by incorporating therein a combination of sequestering agents, one of which is an aminopolyphosphonic acid compound and another of which is an aromatic polyhydroxy compound. Decomposition of the hydroxylamine, in the presence of heavy metals such as iron which act to catalyze the decomposition, and resultant formation of ammonia is effectively prevented by the presence in the developer composition of this combination of sequestering agents. Undesirable precipitate formation is also effectively avoided.

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Rochester, NY, United States of America

Michael D Purol