Tooling of the gold by the impression or stamping of patterns by means of a tool (punch), the tip of which is shaped with a figure or motif. The technique as such is universal, and not restricted to paintings. By some writers confused with the process of incising.

Source: Skaug, Erling. Punch Marks from Giotto to Fra Agelico: Attribution, Chronology, and Workshop Relationships in Tuscan Panel Painting: with Particular Consideration to Florence, c.1330-1430 (Oslo: IIC, Nordic Group, the Norwegian section, 1994), p. 13.