Bright safe light handleable high contrast photographic materials
CA 1339297 C · Owner: Hall, Kevin P. · Inventors: Hall, Kevin P.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A bright light handleable, high contrast negative, acting photographic element having a reduced propensity to formation of pepper fog in which the silver halide emulsion is associated with a hydrazine and a monomethine-benzthiazole compound of the formula: (see fig. I), in which:, one of R1 and R2 represents an organic group containing an acid function and the other is selected from hydrogen, an optionally substituted alkyl group and an organic group containing an acid function.
Read the whole patent
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
- Granted August 19, 1997. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 19, 2014.
- 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.