Fig. 4From: Charcoal or black stone? Reconstructions as a tool to study the behaviour of dry underdrawing materials within the paint structure of sixteenth century panel paintings©HPM, HERCULES Lab—U. Évora, PortugalInfrared details of the underdrawing from paintings of the São Francisco (a) and Sousel (d) altarpieces with the location (green arrow) of the samples viewed in cross-section in the optical microscope under incident light (OM-Vis) (b, e) and ultraviolet radiation (OM-UV) (c, f). All images Back to article page