Abstract: Previously patterned printing plates are washed under a high pressure spray of water that removes unreacted photopolymer or emulsion. The water is sprayed at a pressure of about 500 to about 1000 pounds per square inch, preferably about 800 pounds per square inch. An apparatus for processing plates moves the plates past spray nozzles. The nozzles are supported on a carriage that reciprocates transversely to the direction of movement of the plates, so that the entire surface of each plate is subjected to the direct water spray. The plates are dried under an infrared heater and post cured by ultraviolet light after being washed.