Luma (video)

In video, luma represents the brightness in an image (the "black-and-white" or achromatic portion of the image). Luma is typically paired with chrominance. Luma represents the achromatic image, while the chroma components represent the color information. Converting R'G'B' sources (such as the output of a 3CCD camera) into luma and chroma allows for chroma subsampling: because human vision has finer spatial sensitivity to luminance ("black and white") differences than chromatic differences, video systems can store chromatic information at lower resolution, optimizing perceived detail at a particular bandwidth.