Photographic emulsion containing unfogged, heterodisperse layered silver halide grains having a prodominantly bromide core and total chloride content less than 30 mole percent

US3957488A · kind A · utility

Assignee

• AGFA-Gervaert AG · DE

Inventors

• Sieghart Klotzer · Cologne, DE
• Erik Moisar · Cologne, DE

Key dates

• Filing date: Jun 24, 1974
• Grant date: May 18, 1976
• Expiry date: Jun 24, 1994

Classification

• Technology area (CPC G): Physics
• CPC primary: G03C1/48576
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A photographic material for producing direct-positive photographic images with at least one silver halide emulsion layer containing unfogged heterodisperse silver halide grains with a core which consists predominantly of silver bromide and a localised phase with a high silver chloride content of at least 20 mols-%, the total concentration of silver chloride, based on the total silver halide content of the grain, is less than 30 mols-%, and at least 10% by weight of the silver halide grains have a diameter which deviates by at least 40% from the average grain diameter in which the silver halide grains are not or only slightly chemically sensitised on the surface.