On-press processing of a UV or violet-sensitized lithographic printing plate

A method of making a lithographic printing plate comprising:

• a) image-wise exposing a lithographic printing plate precursor to laser radiation in the wavelength range of from 350 to 450 nm at an energy density in the range from 1 to 150 mJ/cm2, said printing plate precursor comprising:
• a hydrophilic support;
• a negative-working image recording layer which comprises a polymerizable or crosslinkable compound, an initiator, a sensitizer, and a polymeric binder;
• and
• optionally, an overcoat;
• thereby producing a visible image consisting of exposed and non-exposed areas which have a CIELAB 1976 color distance ΔE of at least 2.5, wherein the color distance is measured prior to development;
• and
• b) developing a lithographic printing plate by mounting the plate precursor on a plate cylinder of a lithographic printing press and rotating the plate cylinder while feeding fountain and/or ink to the plate precursor.