Patent ID: 8053170

Claim:
A method of lithographically printing images on a receiving medium, comprising in order: (a) providing a lithographic printing plate comprising (i) a substrate; and (ii) a photosensitive layer soluble or dispersible in ink and/or fountain solution and capable of hardening upon exposure to a laser having a wavelength selected from 200 to 1200 nm; (b) imagewise exposing said plate with said laser on a laser imager to cause hardening of the photosensitive layer in the exposed areas; wherein said imager is connected to a plate cassette for feeding the plate to the imager and is also connected to a plate collector for collecting the exposed plate; and said imager, cassette and collector are shielded with covers so that no room light reaches the plate while the plate is in the cassette, imager or collector, or during the transportation between cassette, imager or collector; (c) picking up said plate from the collector and mounting said plate to a lithographic press; (d) developing said plate with ink and/or fountain solution on said lithographic press to remove the non-hardened areas of the photosensitive layer; and (e) lithographically printing images from said plate to the receiving medium; (f) wherein said imager and press are in a pressroom having a yellow-red light source and a white light source; said yellow-red light source is on and said white light source is off when any part of said covers is opened, when the exposed plate is picked up from the collector to mount to said press, or during at least a 90% by time of said on-press development (step d); and said white light source is on during at least 90% by time of said lithographic printing (step e).