Photographic Lippmann emulsions

US4202695A · kind A · utility

Assignee

• Agfa-Gevaert NV · BE

Inventors

• Herman A. Philippaerts · Edegem, BE
• Robert J. Pollet · Vremde, BE
• Wolfgang Muller-Bardorff · Cologne, DE
• Wilhelm Saleck
• Anita von Konig · Krefeld, DE
• Walter Gauss · Cologne, DE
• Franz Moll · Leverkusen, DE
• Theofiel H. Ghys · Kontich, BE

Key dates

• Filing date: Jan 30, 1975
• Grant date: May 13, 1980
• Expiry date: Jan 30, 1995

Classification

• Technology area (CPC G): Physics
• CPC primary: G03C1/346
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

Fine-grain silver halide emulsions of the Lippmann-type are described which comprise derivatives of heterocyclic mercaptans corresponding to the formulae: ##STR1## wherein: each of Z.sub.1 and Z.sub.2 represents the atoms necessary to complete a 5- or 6-membered heterocyclic ring system, PA1 n is 0 or 1, PA1 X is --CO-- or --CS--, PA1 R is an alkyl group or an aryl group, and PA1 Y is --CO--, --COO--, --CS--, --SO.sub.2 --, --CON(R.sub.1)-- or --CSN(R.sub.1)--, R.sub.1 being hydrogen, alkyl or aryl. Both in reversal and negative processing sharpness of fine detail is improved and the distortion of image-details is reduced. Upon reversal processing yellow staining is also reduced.