In regards to the painter, William Sydney Mount, I was impressed — looking around the web — to see how often he painted musicians, and how sympathetically he depicted African Americans. I kept my college textbook on American Art (Milton W. Brown et. al., Prentice-Hall/Abrams, 1979), and here’s some of what it says about him:
Mount’s treatment of blacks is unusual for the time in its awareness of the social problem. By the very nature of his art anything but an implied comment would have disturbed the harmony of his ideal rural world. But though that comment is unobtrusive and personal rather than political, he represents blacks as human beings and with dignity. The heroic stature of the black woman in Eel Spearing at Setauket (1845) discloses his emotional involvement.