Σκιά and χρῶμα – The Importance of Preliminary Drawing

An important issue in the research on ancient sculptural polychromy is the initial layer applied to a ground, which serves as a base for subsequent layers of paint. It was identified in a number of cases and labelled as ‹underpaint› (in German, Untermalung) or ‹underdrawing› (in German, Unterzeichnung). These definitions have not always been used in a consistent way. In the field of conservation, the common terminology contains a subtle but important difference: underpaint is necessary for giving a nuance or shadow to the final layer, while underdrawing is only a preliminary drawing, a trace to follow in applying the colours. In order to avoid misunderstandings, it is useful to clarify our terminology. In this regard the ancient sources on painting on sculpture are not very helpful, but we can consider the much richer information concerning paintings on wooden panels. In this field, the Greek technical term for ‹underdrawing› is σκιά or σκιαγραφία. The most detailed sources on this process date back to the period of late antiquity, although the earliest attestations are found in the Epistles to the Hebrews and the Colossians from the 1st cent. A.D. Given the widespread diffusion of the underdrawing technique in panel paintings, we are also equipped to interpret the traces found on sculptures according to the same principles.