A method of lithographic plate making is disclosed wherein a plate precursor is exposed to laser radiation in the wavelength range from 350 to 450 nm, said plate precursor comprising a hydrophilic support and a photopolymerizable or photocrosslinkable image recording layer, and then processed on-press by supplying fountain and ink. The exposure produces a visible image having a 1976 CIELAB color distance AF between exposed and non-exposed areas of at least 2.5.

A method of lithographic plate making is disclosed wherein a plate precursor is exposed to laser radiation in the wavelength range from 350 to 450 nm, said plate precursor comprising a hydrophilic support and a photopolymerizable or photocrosslinkable image recording layer, and then processed on-press by supplying fountain and ink. The exposure produces a visible image having a 1976 CIELAB color distance ΔE between exposed and non-exposed areas of at least 2.5.

A lithographic printing plate precursor is disclosed including a support and a coating comprising a sensitizer and an onium salt wherein the onium salt and the sensitizer are capable of inducing a print-out image upon UV light exposure.