Photographic film units containing colorless p-nitrobenzylidene dye-forming compounds
CA 1076409 A · Owner: Eastman Kodak Company · Inventors: Abbott, Thomas I.; Chapman, Derek D.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A photographic film unit comprises a support having coated thereon at least on photosensitive silver halide emulsion, said layer having associated therewith a dye image-providing material, a dye image-receiving layer means for discharging an alkaline processing composition within the film unit and at least one layer containing at least on para-nitrobenzylidene dye-forming compound. Some of the para-nitrobenzylidene dye-forming compounds are a dark color at moderately and highly alkaline conditions and are colorless at neutral or only slightly alkaline conditions such as at ambient conditions. -1-
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 April 29, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 29, 1997.
- 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.