scumble

 
Pronunciation: /ˈskʌmb(ə)l/
Art

verb

[with object]
  • modify (a painting or colour) by applying a very thin coat of opaque paint to give a softer or duller effect: the area surrounding the main figures will be scumbled
  • modify (a drawing) with light shading in pencil or charcoal to give a softer effect.

noun

  • a thin, opaque coat of paint or layer of shading applied to give a softer or duller effect.
  • the effect produced by scumbling.

Origin:

late 17th century (as a verb): perhaps a frequentative of the verb scum