Andrea del Sarto in the context of "Grisaille"

Grisaille (/ɡrɪˈzaɪ/ or /ɡrɪˈzeɪl/; French: grisaille, lit. 'greyed' French pronunciation: [ɡʁizaj], from gris 'grey') is a painting executed entirely in shades of black and grey or of another neutral greyish colour. It is particularly used in large decorative schemes in imitation of sculpture. Many grisailles include a slightly wider colour range.

A grisaille may be executed for its own sake, as underpainting for an oil painting (in preparation for glazing layers of colour over it), or as a model for an engraver or other printmaker to work from. "Rubens and his school sometimes use monochrome techniques in sketching compositions for engravers." By the 19th century many illustrations for books or magazines were made reproducing grisailles in watercolour. Full colouring of a subject makes many more demands of an artist, and working in grisaille was often chosen as being quicker and cheaper, although the effect was sometimes deliberately chosen for aesthetic reasons. Grisaille paintings resemble the drawings, normally in monochrome, that artists from the Renaissance on were trained to produce; like drawings they can also betray the hand of a less talented assistant more easily than a fully coloured painting.