Leaf mold sheets, circa 1950-1970s

Six plastic vaccum-formed leaf sheetes. They were used to create big amounts of leaves casts for exhibits, possibly between the 1950s and 1970s. 

Plastic sheets of cellulose acetate and other types of synthetic thermo-plastic resins were used for molding or drawing. These sheets were made through vacuum-forming. A machine vacuum-draws hot pliable plastic sheets over the leaf plaster molds. This process picks up and transfers all the details of the leaf mold to the plastic sheet. After the sheet cools, each leaf is cut out and has a wire attached to it. Each leaf is then airbrush is natural color. Metal squeeze molds can also be used instead of plaster. In this case, plastic sheets are placed between the molds and clamped tightly under very hot water so that they can take the impression.