Pattern-forming methods and lithographic printing plates

摘要

A method for producing a predetermined pattern in a coating on a substrate, the method comprising: the patternwise delivery of heat to the coating, the coating comprising a positive working composition; and the application of a developer to the patternwise-heated coating; wherein the composition comprises a polymeric substance, and diazide moieties and a cyanine dye not having a borate anion; wherein the diazide moieties comprise 1,4- or 1,2-benzoquinone diazide (BQD) or 1,4-, 2,1- or 1,2-naphthoquinone diazide (NQD) moieties; wherein the composition has the property that it is developer insoluble prior to the delivery of heat and developer soluble thereafter; wherein the heat is delivered via electromagnetic radiation of wavelength entirely or predominantly in the range 600-1400 nm, the cyanine dye absorbing the electromagnetic radiation and converting it to heat.