Decolorizable imaging system

A light insensitive imageable layer comprising a synthetic polymeric binder, and within said binder (1) a dye, (2) a nitrate salt, and (3) an acid, said dye being present in said binder in sufficient concentration to provide an optical density of at least 0.1 in the visible region of the electromagnetic spectrum or to absorb at least 20% of incident radiation in a 50 nm range within the infrared or ultraviolet wavelengths of the electromagnetic spectrum, and said nitrate ion being present in a ratio of at least 0.1 moles/mole of dye, said nitrate salt in said binder being capable of liberating a sufficient quantity of an oxidizing agent selected from the class consisting of HNO.sub.3, NO, NO.sub.2, and N.sub.2 O.sub.4 when heated to 200.degree. C. for 60 seconds to oxidize said dye to a different color or colorless state.