This c. 1739 pastel portrait of Claude Dupouche by Maurice-Quentin de La Tour appeared in an exhibit at the National Gallery of Art entitled “The Touch of Color.” It belongs to the National Gallery in the Kress Collection having been purchased by Samuel H. Kress in 1956 and given to the museum in 1961.
La Tour's contemporaries admired his extraordinary ability to capture personality through fleeting expressions and gestures. Despite the momentary quality of his portraits, he prepared carefully by sketching his sitters as he chatted with them. He gave equal attention to inanimate objects, differentiating between the matte texture of the sitter's coat and the sheen of the chair with a few masterfully placed white highlights on the satin upholstery. -- NGA.
This image was on the exhibition poster, seen here at the checkroom at the National Gallery.