BigPatents India

A method for making a negative-working heat-sensitive lithographic printing plate precursor is provided which comprises the steps of (i) providing a support having a hydrophilic surface or which is provided with a hydrophilic layer, and (ii) applying on said support a coating which comprises a product DQ, wherein DQ is obtained by - the step of coating a solution or dispersion comprising a nucleophilic compound Q and a dye D selected from the list consisting of di- or tri-arylmethane dyes, cyanine dyes, styryl dyes and merostyryl dyes; or by - the step of coating a solution or dispersion comprising said compound Q and coating another solution or dispersion comprising said dye D; wherein D and Q interact to form interaction product DQ. having a white light optical density which is lower than the white light optical density of dye D. and wherein said interaction product DQ is capable of at least partially releasing a dye directly after exposure to infrared light or heat, thereby forming a visible image in said coating.