A tooling of linear freehand patterns in a gilt and burnished surface with a stylus. Preparatory incision in ground, of the parts of the composition prior to gilding and painting, in order to retain the design through the subsequent process of execution.

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. 12.