his is an approach that requires patience, and is not for anyone who's in a rush to get a painting finished or to get the colors sorted. Instead, it involves first creating a monochrome version of the painting that is as finished as the final painting will be, then glazing color over this. For it to work, you need to glaze with transparent colors, not opaque. Otherwise the form or definition created by light and dark tones of the underpainting will be lost.
Depending on what you use for the underpainting, it can be called different things. Grisaille = grays or browns. Verdaccio = green-grays. Imprimatura = transparent underpainting.
