Patent ID: 8703381

Claim:
An on-press developable, negative-working lithographic printing plate precursor comprising a substrate and at least one on-press developable, negative-working radiation-sensitive imageable layer disposed over the substrate, the negative-working radiation-sensitive imageable layer comprising a free radically polymerizable compound, a radiation absorber, a compound to generate free radicals upon irradiation, and a polymeric binder that promotes on-press developability, the substrate comprising a grained and sulfuric acid anodized aluminum-containing support, which support has also been treated with an alkaline or acidic pore-widening solution to provide its outer surface with columnar pores so that the average diameter of the columnar pores is at least 20 nm and up to and including 40 nm, the substrate further comprising a hydrophilic layer disposed directly on the grained, sulfuric acid anodized, and treated aluminum-containing support, the hydrophilic layer comprising a non-crosslinked hydrophilic polymer having carboxylic acid side chains, wherein the non-crosslinked hydrophilic polymer has carboxylic acid side chains that are neutralized to a degree of at least 1 mol % and up to and including 60 mol %.