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:
Jul. 13, 1999
Filed:
Jul. 15, 1997
Applicant:
Inventors:
Charles G Barlow, St. Paul, MN (US);
Richard R Ollmann, Woodbury, MN (US);
Alexis S Zinn-Warner, Maplewood, MN (US);
Robert J Nairne, Bishop's Stortford, GB;
A L Beck, Hertford, GB;
Andrew Mott, Bishop's Stortford, GB;
Assignee:
Imation Corp., Oakdale, MN (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03C / ; G03C / ;
U.S. Cl.
CPC ...
430611 ; 430600 ; 430603 ; 430613 ; 430965 ;
Abstract
A black-and-white, negative-acting, silver halide emulsion is described which gives improved image tone when used in a photographic element. The toning agents are based on dithio-substituted compounds having the following general structures: ##STR1## where R.sub.1 and R.sub.2, independently, are selected from the group consisting of alkyl, aryl and heterocyclic groups, or R.sub.1 and R.sub.2 together complete a ring;