Ébauche Underpainting
A thin, fully-worked tonal underpainting of the whole composition—more complete than an imprimatura wash, less finished than a first paint layer.
The ébauche is a French academic invention: a first pass at the whole painting in diluted earth tones that establishes figures, values, and compositional structure without committing to local color or surface detail. Bouguereau built every major canvas over an ébauche. Zorn referred to the same step in his own practice, working from a gray-red ground into a thin tonal block-in before opaque color arrived. The virtue is that the entire painting exists in a coherent state before any passage is brought to finish, which stops the common failure mode of over-resolving one area while the rest remains in sketch.