Abstract: A negative waterless plate contains a sheet substrate; a radiation sensitive imaging layer composed of a diazido naphthaquinone ester or amide compound, such as diazido naphthaquinone sulfonate of a phenolic resin, and a polyurethane prepared by reacting a di-isocyanate and a diol; and a silicone layer. The planographic printing plate is imagewise exposed to actinic radiation through a negative original to form exposed areas of the imaged layer which are soluble or dispersible in a developer liquid. After imaging exposure, the developer liquid is applied which penetrates the silicone layer and dissolves the areas exposed to the radiation. The coating areas not exposed by the radiation remain intact. During this development procedure, areas of the silicone layer overlying the exposed areas are removed along with the underlying soluble areas to produce an imaged planographic printing plate having uncovered ink receptive areas and complimentary ink repellent areas of the silicone layer.

Abstract: Presensitized lithographic plates are prepared which permit direct formation of printable images on plates by digital computerization without the intervening formation of a photographic image with a quality that allows the plates to be used for high volume printing applications. The lithographic printing plate has a structure which contains a substrate; a positive or negative working photosensitive layer; and a thermally sensitive masking layer which is opaque to the actinic radiation but which is soluble in an aqueous medium. The masking layer contains a heat softenable disperse phase which is insoluble in the aqueous medium; a polymeric continuous phase which is soluble or swellable in the aqueous medium; and a colorant which strongly absorbs radiant energy and converts the radiant energy to heat.