Portrait of the Artist’s Son, Jonathan Richardson the Younger, in his Study c.1734 by Jonathan Richardson | Tate https://www.tate.org.uk/about-us/projects/tudor-stuart-technical-research/entries/portrait-of-the-artists-son-jonathan-richardson-the-younger-in-his-study-c1734-by-jonathan-richardson
made to losses in the paint and ground without filling and levelling, resulting in depressions