Overglaze hot press printing with pigment

Stage 1: engraving or etching the copper plate

The first stage was to engrave the design into the surface of a copper plate. Engraving means cutting into the metal with a sharp steel tool called a burin, or indenting dots with a punch. Sometimes the plate was coated with a wax which protects it from the acid and is known as a ‘resist.’ The design is then lightly etched as well as engraved. Etching uses acid to bite into the surface of the copper. The plate is first scratched through the wax. The plate is then exposed to the acid. The acid bites into the copper wherever the design has been scratched through the wax. The result of both engraving and etching is a plate with the design cut into its surface.








 Stage 2: transferring the design from the copper plate to the glue bat

In the glue bat method, the printer did not heat the copper plate. Boiled linseed oil was rubbed into the lines of the plate.

The surface of the plate was carefully wiped clean, so that oil remained only in the lines. A sheet of gelatine, known as a bat, was then pressed on to the copper plate. This transferred the oil from the plate to the bat. The flexible bat was then peeled off from the plate.