Historical reference: Do not rely on this information. It is very old. About this collection
Fothergill's Process, a process used for the formation of a photographic dry plate. The method was (1) to coat a glass plate with collodion containing dissolved nitrate of silver, and (2) pour over the coated plate a solution of albumen containing sal-ammoniac (NH4C1) dissolved in it, and then allow the plate to dry.