Apparatus and method for exposing a lithographic printing plate wherein the apparatus includes a plurality of laser diodes emitting light of wavelength between 350 nm and 450 nm. The light from each of the laser diodes is directed onto the lithographic printing plate such that each spot on the lithographic printing plate receives light emitted from at least one of the laser diodes. Preferably, the lithographic printing plate is a violet-sensitive lithographic member and the lithographic member is a printing press plate. The power of each laser diode may be between 5 mW and 30 mW, and preferably the laser diodes emit light of wavelength between 390 nm and 430 nm.