EP 0182658 A2 19860528 - Photographic coupler dispersions.
Title (en)
Photographic coupler dispersions.
Title (de)
Photographische Kupplerdispersionen.
Title (fr)
Dispersions de coupleur photographique.
Publication
Application
Priority
GB 8429677 A 19841123
Abstract (en)
The dark stability of a photographic dye image formed by reaction between a coupler, dispersed in admixture with an involatile solvent, and oxidized p-phenylenediamine colour developing agent is impaired by the presence of a compound comprising a phenolic (or naphtholic moiety in which the acidity of the phenolic hydroxyl group is enhanced by at least one electron-withdrawing substituent in ortho and/or para positions relative to that group. Such a compound may be the coupler itself of the involatile solvent used for its incorporation. This loss in stability can be reduced by introducing into the dispersion a lipophilic anionic surfactant which comprises a sulphate or sulphonate group as the sole hydrophilic group and either a single aliphatic hydrocarbon group having at least 15 carbon atoms or two or more aliphatic hydrocarbon groups which together contain at least 17 carbon atoms. A conventional, i.e. less lipophilic, anionic surfactant may also be used in preparing the coupler dispersion.
IPC 1-7
IPC 8 full level
G03C 7/34 (2006.01); G03C 7/388 (2006.01)
CPC (source: EP)
G03C 7/3885 (2013.01)
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
EP 0182658 A2 19860528; EP 0182658 A3 19880113; EP 0182658 B1 19900425; CA 1261190 A 19890926; DE 3577358 D1 19900531; GB 8429677 D0 19850103; JP S61184542 A 19860818
DOCDB simple family (application)
EP 85308436 A 19851120; CA 494801 A 19851107; DE 3577358 T 19851120; GB 8429677 A 19841123; JP 26470085 A 19851125