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:
Jan. 04, 1977
Filed:
Apr. 01, 1974
Applicant:
Inventors:
Eva R Karger, Arlington, MA (US);
Paul T MacGregor, Lexington, MA (US);
Assignee:
Polaroid Corporation, Cambridge, MA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07D / ;
U.S. Cl.
CPC ...
2603 / ; 2603 / ; 96 2 / ; 96 2 / ; 96 6 / ; 96 7 / ; 96 77 ; 96 8 / ;
Abstract
This invention relates to a class of 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 one of the 3,3-substituents is an indol-3-yl radical substituted with hydrogen on the heterocyclic N atom and the other of said 3,3 substituents is a p-hydroxycarbocyclic aryl radical selected from a 4'-hydroxy-1'-phenyl radical and a 4'-hydroxy-1'-naphthyl radical.