Luminance Luminance

Luminance - Definition and Overview

The word luminance, a synonym for luminosity, means emitting or reflecting light.

As applied to analog television signals, two different words are used, luminance and luma, meaning two different things. Luma is a new word proposed by the NTSC in 1953 to prevent confusion between the Y' component of a color signal and the traditional meaning of luminance. While luminance is the weighted sum of the linear RGB components of a color video signal, proportional to intensity, luma is the weighted sum of the non linear R'G'B' components after gamma correction has been applied, and thus is not the same as either intensity or luminance.

An incorrect luma setting can cause visible flicker in a television display.

Luminance can be calculated from (0.299R+ 0.587G + 0.114B).

SI light units

SI light units

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Quantity SI unit Symbol Notes
Luminous energy joule J
Luminous flux lumen or ( candela · steradian ) lm also called Luminous power
Luminous intensity candela cd
Luminance candela / square metre cd/m2 also called Luminosity
Illuminance lux or (lumen / square metre) lx
Luminous efficacy lumens per watt lm/w

See also

Example Usage of Luminance
LRSecrets: @FTUdotcom Luminance Noise Reduction slider is disabled in the LR3 beta. Only Color Noise Reduction is active for the beta.
FTUdotcom: Lightroom 3 Beta Luminance noise reduction issue: Hi folks, I've been using LR3 beta for a while now (64 bit.. http://bit.ly/08nYQvD
Christinamok: GM COLLIN Luminance CONCENTRATE free cell phone stand http://shop.ebay.com/320451957481
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