Sir Lawrence Alma Tadema is known for highly finished paintings of Roman life. But during his development stages, he could be pretty loose and improvisational.
(Click to enlarge.) There are a few unfinished paintings that suggest he switched gears part way through the painting and introduced new figures with a brush. They’re drawn in quickly with a thin sable brush to establish an outline. The face of the lower woman is roughly blocked in with simple planes. The skin tones of the farthest figure has been filled in with a semi-opaque scumble. The middle figure has been refined another step forward.
This unfinished painting shows what a painting might look like in the midst of rethinking and reworking. This time he’s drawing outlines in a light opaque medium (I’m not sure what it is--chalk? white oil?). He seems to be trying to place one or more male faces on the right.
The modulation of tones and edges in the main face has been taken farther along.
Ideally major changes should be done over sections where the paint has been scraped down to the priming, to avoid pentimenti from showing up later.
Wikipedia on Tadema
Alma Tadema Complete Works on the web
Pentimento on Wikipedia
Alma-Tadema: The painter of the Victorian vision of the ancient world
Previously: Tadema's Antony and Cleopatra