Agfa-gevaert Ag

Max Heilmann

Karl Frank

An aqueous alkaline developer mixture for preparing color photographic images containing a color developer of the p-phenylenediamine series a hydroxylamine compound and a hydroxyalkylidenediphosphonic acid or a water soluble salt of the said acid and at least a compound of the aminopolyphosphonic acid or of the aminopolycarboxylic acid series with improved resistance to oxidation and resistance to the formation of chalk deposits and high stability in storage.

Photographic color developer mixture

Color film of the silver halide emulsion type is developed by a process which includes a bleach-fixing bath treatment to remove the silver image, followed by an oxidizing bath to restore to the dyes the color which they lost in the bleach-fixing bath. This oxidizing bath must contain an iron-III-complex of an amino polyacetic acid as the oxidizing agent, e.g. the sodium-salt of the iron-III-complex of ethylene diamine tetra-acetic acid.

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Cologne, Germany

Max Heilmann