Color
Relative luminance
Each channel is linearised and then weighted by the eye's sensitivity, which is highest for green.
The Formula
L = 0.2126 R + 0.7152 G + 0.0722 B (gamma corrected)
Each channel is linearised and then weighted by the eye's sensitivity, which is highest for green.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| R' | Linear red | 0-1 | Red channel after the sRGB gamma correction. |
| G' | Linear green | 0-1 | Green channel after the sRGB gamma correction. |
| B' | Linear blue | 0-1 | Blue channel after the sRGB gamma correction. |
What Each Symbol Means
R'0-1
Linear red
Red channel after the sRGB gamma correction.
G'0-1
Linear green
Green channel after the sRGB gamma correction.
B'0-1
Linear blue
Blue channel after the sRGB gamma correction.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to convert colors page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Convert Colors, filed under Unit Conversion. Every number the guide produces comes from substituting into this one line.