(57) @ 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 1 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.