1) Tone 
• (n.) That part of a painting, engraving, or the like, which is neither in full darkness nor full light. • (n.) The shade itself; neither the darkest nor the lightest in a composition. Also called half tint.
Dem'i·tint` noun (Fine Arts) (a) That part of a painting, engraving, or the like, which is neither in full darkness nor full light. (b) The shade itself; neither the darkest nor the lightest in a composition. Also called half tint .