The unexposed polymer is affected by water and ultraviolet light.
Etching is created by washing out the blocked areas with tap water.
The plate has been designed for long printing life and excellent Ink receptivity. The artist may draw or paint or lay objects directly on the plate and expose it. A typical photocopy in New York at noon time in the early fall may be about 2 minutes. There is a pretty wide latitude of exposure time and is not critical for the single exposure. Since Dan Welden's development of the process in the 70's .