Photographic bleaching solution and use thereof in photographic color processing
CA 2073765 A1 · Owner: Foster, David G. · Inventors: Foster, David G.; Stephen, Keith H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An environmentally advantageous photographic bleaching solution for use in the color processing of photographic elements comprises (1) as a bleaching agent, a potassium salt of a ferric complex of an aminopolycarboxylic acid, (2) as an agent which functions to convert silver to silver halide, a potassium halide and (3) as , an agent which functions to inhibit bleach induced dye formation a water-soluble aliphatic carboxylic acid. The bleaching solution is especially useful in the processing of photographic elements containing a low pKa, high-activity, yellow-dye-forming coupler in that it serves to effectively avoid the undesirable increase in blue Dmin that can occur in such elements as a …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed January 18, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended January 18, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 18, 2013.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.