Formal- A thickness of some material laid on over a surface.
Informal- materials or Objects Layered on top of each other.
Informal-the clearness of an object.
Formal- spatial contrast by the use of illusionistic devices such as the placement of a large figure or object in the immediate foreground of a painting to increase the illusion of depth in the rest of picture.
Informal- making it so that the background is looks really far.