Blend modes (or mixing modes) in digital image editing and computer graphics are used to determine how two layers are blended with each other. The default blend mode in most applications is simply to obscure the lower layer by covering it with whatever is present in the top layer (see alpha compositing); because each pixel has numerical values, there also are many other ways to blend two layers. In the formulas shown on this page, values go from 0.0 (black) to 1.0 (white).