The underdrawing
composition on the ground layer. Although
covered over with paint, they can be
revealed with infrared light. Some artists
used underdrawings as rigid guides
for the brush; others sketched more freely
and did not precisely follow their
underdrawings in paint.
Knowledge of these characteristics can help in solving questions of attribution. Sometimes, they can lead scholars to distinguish an original composition from a copy.
The artist of Portrait of a Man carefully followed the underdrawing in paint. The position of the nostril was prepared with a single line, for example, and dark zones were precisely indicated with parallel hatching.
Click here to compare a visible light image with an infrared image. Requires shockwave plug-in.
Visible Ultraviolet Infrared X-ray Verso