A method for making a lithographic printing plate includes the steps of providing a printing plate precursor including a support and photosensitive coating wherein the photosensitive coating includes a photopolymerizable composition; image wise exposing the printing plate precursor on an external drum apparatus emitting one or more scanning laser beams having a wavelength between 390 nm and 420 nm and an energy density, measured on the surface of the precursor, of 100 μJ/cm2 or less; optionally preheating the printing plate precursor; and processing the exposed printing plate precursor with a developer.