Patent · US Expired

Process for the production of direct-positive photographic images

US4139387A · kind A · utility

8Cited by

5References

6Claims

0Family size

Assignee

Agfa-Gevaert NV · BE

Inventors

Anita von Konig · Krefeld, DE
Heinrich Odenwalder · Leverkusen, DE
Manfred Peters · Bad Schwartau, DE
Walter Puschel · Leverkusen, DE

Key dates

Filing date	Nov 3, 1977
Grant date	Feb 13, 1979
Priority date	—
Expiry date	Nov 3, 1997

Classification

Technology area (CPC G)Physics
CPC primaryG03C5/50
WIPO fieldOrganic fine chemistry
WIPO sectorChemistry

Abstract

Positive images including color images are obtained by imagewise exposure and development of a material which comprises at least one light-sensitive silver halide emulsion layer which contains an unfogged direct-positive silver halide emulsion, when the development is carried out in the presence of a fogging agent of the formula ##STR1## wherein the symbols are defined as hereinafter. The fogging agent is preferably contained in a layer of the material and more preferably in the unfogged direct-positive silver halide emulsion layer. For the production of color instant images the material may also contain non-diffusible color providing compounds capable in their oxidized form of being split under alkaline photographic development conditions to release diffusible dyes.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.