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:
Aug. 17, 1982
Filed:
Oct. 06, 1980
Richard L Cournoyer, Dorchester, MA (US);
James W Foley, Andover, MA (US);
Polaroid Corporation, Cambridge, MA (US);
Abstract
The present invention is concerned with photographic products and processes employing certain pH-sensitive xanthene compounds as light-screening dyes, which compounds may be represented by the formulae ##STR1## wherein A and A', the same or different, are selected from ##STR2## each R is hydrogen or an electron-withdrawing group; each R.sup.1 is hydrogen or alkyl; each R.sup.2 is hydrogen, alkyl or an electron-withdrawing group; R.sup.3 is hydrogen or alkyl; R.sup.4 is alkyl; and n is 0 or 1 and which compounds in their colored, i.e., ring-opened form may be represented by the formulae ##STR3## wherein A, A', R.sup.3, R.sup.4 and n have the same meaning given above and Z is an anion.