Patent ID: 8247163

Claim:
A method of preparing a lithographic printing plate comprising: A) imagewise exposing a negative-working lithographic printing plate precursor comprising a substrate and a radiation-sensitive imageable layer disposed thereon comprising a free radically polymerizable compound, a radiation absorbing compound, a free radical initiator composition, and a polymeric binder to provide an exposed precursor having solid exposed regions and non-exposed regions in said imageable layer wherein said solid exposed regions have an optical density of OD 1 , wherein said radiation-sensitive imageable layer is the outermost layer of said negative-working lithographic printing plate precursor, B) applying a coloring fluid to said exposed precursor such that the optical density in said solid exposed regions is OD 2 that is greater than OD 1 , said coloring fluid comprising a water-insoluble colorant and a solvent that is capable of swelling said solid exposed regions of said imageable layer.