A method of processing an on-press developable lithographic printing plate with ink and/or fountain solution is described. The plate comprises on a substrate a photosensitive layer which is either capable of hardening (negative-working) or solubilization (positive-working) upon exposure to a laser, the non-hardened or solubilized areas of the photosensitive layer being soluble or dispersible in ink and/or fountain solution. The plate is exposed with a laser, heated to an elevated temperature, and then developed with ink and/or fountain solution on a lithographic press. The laser exposed plate is preferably heated by passing through a heating device or while mounted on a lithographic press before on-press development.