halftone A digital process used to create the effect of shading with a wide range of gray values or colors when only two-level pixel values or a much limited range of values is available. By varying the ratio of black to white pixels in each small area of the screen, the eye sees a continuous intensity at normal viewing distance due to the limited resolving power of the eye. (The printing industry uses dots of ink whose size or density varies.)

half·tone / ˈhafˌtōn/ • n. [usu. as adj.] a reproduction of a photograph or other image in which the various tones of gray or color are produced by variously sized dots of ink: halftone illustrations.