The Collaborative International Dictionary of English v.0.48:

lithographer \li*thog"ra*pher\, n.
   One who lithographs; one who practices lithography.
   [1913 Webster] lithographic

WordNet (r) 3.0 (2006):

lithographer
    n 1: a printmaker who uses lithography

Moby Thesaurus II by Grady Ward, 1.0:

18 Moby Thesaurus words for "lithographer":
   burinist, carver, cerographer, chalcographer, engraver, etcher,
   gem engraver, graphic artist, graver, inscriber, lapidary,
   line engraver, printmaker, pyrographer, serigrapher,
   silk-screen artist, wood engraver, xylopyrographer