black up
verb1
Literally To become or make (something) black or darker.
2
To put on or wear blackface makeup.
- Cantor starts blacking up, right then and there, painting his face with a burnt piece of cork.2016, Zadie Smith, Swing Time, New York, N.Y.: Penguin Press, →ISBN, page 191:
3
To make something (e.g. a film, cast, story line, etc.) more racially black in character; blackenize.