The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 16, 1976
Filed:
Aug. 27, 1973
Stanley M Bloom, Waban, MA (US);
Elbert M Idelson, Newton Lower Falls, MA (US);
Myron S Simon, West Newton, MA (US);
David P Waller, Arlington, MA (US);
Polaroid Corporation, Cambridge, MA (US);
Abstract
This invention relates to a class of phthalein indicator dyes useful as optical filter agents in photographic processes to protect a selectively exposed photosensitive material from further exposure during processing in the presence of incident light. Such dyes comprise 3,3-disubstituted phthalides and 3,3-disubstituted naphthalides wherein the 3,3 substituents are p-hydroxy carbocyclic aryl radicals wherein one or both of the radicals possess a --CH.sub.2 --NRR' group ortho to the p-hydroxy group and the --CH.sub.2 --NRR' group(s) is capable of rendering the indicator dye substantially non-diffusible in aqueous solution.