Term
Core shadow
Meaning
A core shadow is the darkest band on the shadow side of a form, found just beyond the terminator where the surface turns fully away from the light. It is separate from the cast shadow that the form throws onto the surface it sits on. Keeping the two apart makes shading clearer, and keeping the shadow side from becoming pure black prevents a flat look, because a little light bounces back into it. See also: Terminator, Reflected light, Value and the guide "Torso, Mannequins and Light on Form: Building Solid Figures".