Video Production Luminance

Luminance

As applied to video production, luma represents the brightness in an image (the "black and white" or achromatic portion of the image). Luma is typically paired with chroma. Luma represents the achromatic image without any color, while the chroma components represent the colour information. Converting R'G'B' sources (i.e. the output of a 3CCD camera) into luma and chroma allows for chroma subsampling, enabling video systems to optimize their performance for the human visual system. Since human vision is more sensitive to luminance ("black and white") detail than colour detail, video systems can optimize bandwidth for luminance over colour.

While luma is more often encountered, (photometric) luminance is sometimes used in video engineering and production when referring to the brightness of a monitor. The formula used to calculate luminance used coefficients based on the CIE colour matching functions and the relevant standard chromaticity of red, green, and blue is:

Y = 0.2126 R + 0.7152 G + 0.0722 B