underpainting

A monochrome colour application serving as a base for colour modelling. It is most often applied to fresh plaster using the al fresco technique. It serves as the following: a) the basic modelling for the figures, to which the appropriate colours are applied later; b) a base for the pigments that are not stable in the alkaline lime or wet plaster, are not sufficiently opaque on their own, or need to be used sparingly due to their considerable price. See headwords morello, caput mortum, veneda, verdaccio.