Negative-working diazotype photoreproduction

Negative-working diazography material is comprised of (i) at least one diazonium compound, (ii) at least one acid labile enolic, preferably phenolic blocked-coupler adapted to be converted in the presence of acid to an active azo-coupling component, and (iii) at least one light-sensitive acid progenitor. The diazonium compound can itself concurrently function as the acid progenitor, e.g., when complexed with a Lewis acid. Upon imagewise exposure to light, acid catalyst is photochemically liberated, thus unblocking coupler molecules such that dye image forms under alkaline developing conditions only where the material has been irradiated.