Layering Paint - Underpainting

As said previously, drawing and painting are ultimately inseparable activities, and underpainting is often confusingly termed underdrawing .But this at least elucidates its function. In the 15th century both northern and southern European artists, having prepared their panels, would usually draw on these with dry media, and then reinforce this design, often modelling it out with cross-hatching, using thinned grey or reddish-brown ink or paint. Such preliminary work guided subsequent development, and enriched the semi-transparent thinned colour placed on top: a warm brown underpainting, for instance, would prevent a dark red from appearing too purplish.