These .73mm steel backed solar plates are supplied by Vermont PhotoInkjet to printmakers who produce relief prints, etchings, intaglios and photogravures without using grounds, nor acids, nor even solvents! The plates can be painted on directly or used with printed film and then exposed to sun or strong UV and then developed in ordinary tap water! The processed plates are hand wiped or rolled with etching or relief inks and printed with an etching press. Our plates are Polyvinyl Alcohol based, SDS exempt, and considered to be the safest non-toxic plate available. When in stock, these plates ship same day when ordered before noon!