what is grisaille

This painting en grisaille demonstrates how an understanding of light value is just as important as color for a successful result.

Grisaille definition

Grisaille (pronounced like Versailles) underpainting is an oil painting technique in which a composition is constructed completely in tones of gray. It is often used for underpainting, since it establishes light values underneath transparent oil glazes. It can also be used in pastel compositions, albeit differently, since pastels are opaque.