PRESERVING METHOD OF BLEACHHFIX BATH FOR COLOR PHOTOGRAPHIC PROCESSING

摘要

PURPOSE:To improve the shelf stability of a bleach-fix bath contg. the ferric salt of aminocarboxylic acid and thiosulfate for color photographic processing by adjusting the ferrous ion concn. to a specified value and adding an effective amount of a preservative. CONSTITUTION:Ferrous ions obtd. by reducing the ferric salt of aminopolycarboxylic acid are added to a bleach-fix bath contg. the ferric salt of aminocarboxylic acid such as ferric ammonium ethylenediaminetetraacetate as a bleaching agent and thiosulfate as a fixer to adjust the ferrous ion concn. to the total iron ion concn. to >=10wt%. A preservative such as ammonium sulfite is then added to the bath by an effective amount which is more than the amount of the preservative consumed by aminopolycarboxylic acid during the period of preservation.