atmospheric perspective- sequentially using lighter colors for each region of the painting. This technique creates a sense of distance for objects that are distant in the painting chiaroscuro- using light and shadow to define forms codex- book composed of folded sheets sewn along one edge optics- the branch of physics that studies the physical properties of light sfumato- (from the Italian for smoke) an imperceptible, subtle transition from light to dark, without any clear break or line