(1) (Color Key) See prepress proof.
(2) Also called "chroma key," it is a technique for superimposing one video image onto another. Widely used to place an interesting scene behind people such as a news reporter on TV, it is also used for creating special effects such as floating a car on the ocean. The Blue or Green Screen The foreground image is shot in front of a backdrop, which is a single, solid color, typically blue or green. When both images are combined, the background pixel takes precedence wherever a pixel of the solid color is found in the foreground image. If the foreground image is a person and the backdrop is blue, no articles of blue clothing can be worn or the background image will bleed through in those locations.