Patent ID: 8158331

Claim:
A method of making a relief image printing element from a photosensitive printing blank, said photosensitive printing blank comprising a laser ablatable layer disposed on at least one photocurable layer, the method comprising the steps of: a) selectively laser ablating the laser ablatable layer to create an in situ mask and uncovering portions of the photocurable layer; b) exposing the laser ablated printing blank to at least one source of actinic radiation through the in situ mask to selectively cross link and cure portions of the photocurable layer, wherein the diffusion of air into the at least one photocurable layer is limited during the exposing step by a method selected from at least one of: i) laminating a barrier membrane to the in situ mask and any uncovered portions of the photocurable layer using pressure and/or heat before step (b); and ii) coating the in situ mask and any uncovered portions of the photocurable layer with a layer of liquid prior to step (b); wherein the oxygen diffusion coefficient of the barrier membrane and/or the layer of liquid is less than 6.9×10 −9 m 2 /sec.