Abstract: Hydrophilic coupler-oil solutions are stabilized by the addition of an epoxide compound. These coupler compounds are dissolved, with the aid of epoxide compounds, in high boiling esters and dispersed in aqueous gel solutions to form dispersions of improved stability.

Abstract: A diazotype material, which comprises a supported light-sensitive layer comprising a light-sensitive, water-insoluble diazoimino compound of the formula: ##STR1## wherein R is an aryl group and R.sub.1 and R.sub.2 are organic radicals, which may be the same or different, or R.sub.1 and R.sub.2 together with the nitrogen atom to which they are attached form a heterocyclic group, an azo coupler, and an alkaline material, said diazoimino compound, when exposed to ultraviolet light, being reactive with said azo coupler to form a visible dye product only at a pH greater than 7. The diazotype material can be used for diazotype reproduction processes resulting in negative or direct positive images.