Patent ID: 8530143

Claim:
A method for providing a lithographic printing plate comprising: A) imagewise exposing a positive-working lithographic printing plate precursor having a grained aluminum-containing and sulfuric acid or phosphoric acid anodized substrate comprising an anodic oxide film and having an imageable layer comprising an infrared radiation absorbing compound thereon, to infrared radiation to provide exposed and non-exposed regions in the imageable layer, and B) processing the exposed lithographic printing plate precursor with a silicate-free alkaline aqueous developer composition to remove the exposed regions in the imageable layer, wherein the silicate-free alkaline aqueous developer composition has a pH of at least 12, and comprises: a metal cation M 2+ selected from barium, calcium, strontium, and zinc cations, and a chelating agent that has a complex formation constant (log K) for the metal cation of at least 3.5 and less than or equal to 4.5, and a log K for aluminum ion that is 7 or less.