In
colorimetry and
color theory,
lightness, also known as
value or
tone, is a representation of variation in the perception of a
color or
color space's
brightness. It is one of the color appearance parameters of any
color appearance model. Lightness is a relative term. Lightness means
brightness of an area judged relative to the brightness of a similarly illuminated area that appears to be white or highly transmitting. Lightness should not be confused with brightness.