Luminance: Meaning (information, definition, explanation, facts)

The word luminance, a synonym for luminosity, is an ancient word that means the quality of being luminous; emitting or reflecting light.

Luminance is not an abbreviation of luma. Luma is a new word proposed by the NTSC (II) in 1953 with just one purpose - to prevent misunderstanding about the Y' component of a color system as being the same thing as luminance.

Luminance is the weighted sum of the linear RGB components, proportional to intensity.

Luma is the weighted sum of the non linear R'G'B' components after the gamma correction has taken place, thus it is not the same as intensity or luminance.

An incorrect luma setting can also cause visible flicker.