Regeneration of bleach-fix solutions used in photographic processing
Abstract
Abstract PHOTOGRAPHIC BLEACH-FIX SOLUTIONS EMPLOYING A FERRIC SALT OF AN AMINOPOLYCARBOXYLIC ACID AS BLEACHING AGENT AND A THIOSULFATE AS FIXING AGENT ARE REGENERATED BY REDUCING THE CONCENTRATION OF SILVER ION IN THE SOLUTION TO A LOW LEVEL AND MIXING THE SOLUTION WITH OXYGEN IN AN AMOUNT SUFFICIENT TO CONVERT SUBSTANTIALLY ALL FERROUS ION IN THE SOLUTION TO FERRIC ION. REMOVAL OF SILVER FROM THE SOLUTION CAN BE EFFECTED BY ADDITION OF A CHEMICAL PRECIPITANT, BY METALLIC REPLACEMENT, OR BY ELECTROYLTIC RECOVERY AND THE NECESSARY CONTACT WITH OXYGEN AFTER SILVER REMOVAL CAN BE ACCOMPLISHED BY AERATING THE SOLUTION. TREATMENT OF SPENT BLEACH-FIX SOLUTIONS IN THIS MANNER WILL ESSENTIALLY RESTORE THEIR ORIGINAL BLEACHING AND FIXING CAPABILITIES AND THEREBY PERMIT THEIR REUSE IN PHOTOGRAPHIC PROCESSING.
Inventors
- 👤 Austin C Cooley
Bibliographic Details
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