Literally, “halfway gold,” term known from Trecento and Quattrocento sources. Substitute for gold leaf. Not an alloy as commonly presumed, but probably the laminate consisting of silver base with a thin gold layer on top, used elsewhere in Europe as Zwischgold, Twistgold, gedeelt Gold, etc. (Germ.); partijtgould (Dutch); and or parti (Fr.). Parallel term argentum superauratum.

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), pp. 12-13.