Method of Making Relief Image Printing Elements

A method of flood exposing a photocurable printing blank to actinic radiation from one or more UV LED light sources, wherein the one or more UV LED sources each have an output intensity of at least 200 mW/cm2, the photocurable printing blank comprising a support, at least one photocurable layer upon the support, wherein the at least one photocurable layer is capable of being selectively crosslinked and cured upon exposure to actinic radiation and wherein the at least one photocurable layer comprises (a) at least one elastomeric binder, (b) at least one ethylenically unsaturated monomer, (c) a photoinitiator having a favorable absorption profile in the desired wavelength region used for exposing the at least one photocurable layer to actinic radiation, and a photographic negative or digitally imaged mask layer disposed on the at least one photocurable layer;

• the method comprising the steps of:
• a) positioning the photocurable printing blank in an exposure unit, wherein the exposure unit comprises the one or more high intensity UV LED light sources;
• b) modulating intensity of the one or more high intensity UV LED light sources to a lower intensity, wherein the modulated intensity is less than 100 mW/cm2 at a surface of the photocurable printing blank;
• and
• c) flood exposing the photocurable printing blank through the photographic negative or the digitally imaged mask layer to actinic radiation from the one or more modulated UV LED light sources;
• wherein portions of the at least one photocurable layer not covered by the photographic negative or digitally imaged mask layer crosslink and cure to create the relief image therein.