Audio: The phenomenon by which loud sounds prevent the ear from hearing softer sounds of similar frequency. The process of blocking out portions of a picture area/signal. A psychoacoustic phenomenon whereby certain sounds cannot be heard in the presence of others.

Video: A process to alter color rendition in which the appropriate color signals are used to modify each other. Note: The process is usually accomplished by suitable cross coupling between primary color-signal channels.

Photography: Comparable control of color rendition is accomplished by the simultaneous optimization of image dyes, masking dyes, and spectral sensitivities.