Gradation-variable black-and-white paper

US5006455A · kind A · utility

Assignee

• Agfa-Gevaert NV · BE

Inventors

• Walter Patzold · Leverkusen, DE
• Helmut Kampfer · Idar-Oberstein, DE

Key dates

• Filing date: Nov 10, 1988
• Grant date: Apr 9, 1991
• Expiry date: Nov 10, 2008

Classification

• Technology area (CPC G): Physics
• CPC primary: G03C2001/03564
• WIPO field: Optics
• WIPO sector: Instruments

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.