Underpainting
A multi-color underpainting was thought to be more useful by artists such as Giotto ( whose technique is described in detail by Cennino Cennini ) , as well as by Jan van Eyck and Rogier van der Weyden ( whose technique has been studied with modern scientific analysis ) . 
<triplet> Cennino Cennini <subj> Giotto <obj> influenced by