Dithering
From The Glossary of Digital Photography
The use of two colors of pixels to simulate a third color, or the use of black-and-white pixels to simulate grayscale in images. This is the computer technique used to display images on devices with different color palettes without having to convert the colors. Dithering is used to blend areas that would otherwise band in compressed images, to create halftones for printing, and to create shading and fills. It is also used as an anti-aliasing technique to smooth jagged lines. Regular dithering uses a pattern of two different colors. Diffusion dithering uses randomly placed pixels of two different colors to accomplish the same thing. See also diffusion dithering; anti-aliasing; halftone
