Abstract: A method of treating a plate comprising a substrate carrying an image includes the step of providing a shield on the plate prior to heating the plate so as to prevent contaminants contacting the plate during the heating step. The plate may be a radiation sensitive plate which has been image-wise exposed and developed and which comprises a substrate coated with a radiation sensitive layer comprising for example a quinone diazide and a novolak resin. The radiation sensitive plate may be for the production of a lithographic printing plate and the shield may be in the form of, for example, a layer of a salt such as sodium dedecyl phenoxy benzene disulphonate.