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:
Apr. 09, 1991
Filed:
Nov. 10, 1988
Applicant:
Inventors:
Walter Patzold, Leverkusen, DE;
Helmut Kampfer, Cologne, DE;
Assignee:
Agfa-Gevaert Aktiengesellschaft, Leverkusen, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G03C / ; G03C / ;
U.S. Cl.
CPC ...
430571 ; 430611 ; 430613 ;
Abstract
A gradation-variable BW paper comprising only one silver halide emulsion layer, in which re-sensitization is avoided, is obtained with a mixture of at least two photosensitive silver halide emulsions, of which one has its absorption maximum in the range from 480 to 580 while the other has its absorption maximum below 480 nm, providing the emulsion which has its absorption maximum below 480 nm contains a compound corresponding to the following formula ##STR1## in which X represents the remaining members of an optionally benzo- or naphtho-condensed heterocycle optionally containing further substituents.