Sources:
U/Udzu, Flags of the World, Sorted by Average Hue, Reddit.com, August 29, 2018, https://www.reddit.com/user/Udzu.
Wikipedia, sRGB, https://en.wikipedia.org/wiki/SRGB.
Wikipedia, Gamma correction, https://en.wikipedia.org/wiki/Gamma_correction.
sRGB (standard Red Green Blue) is an RGB color space that HP and Microsoft created cooperatively in 1996 to use on monitors, printers, and the Internet. It was subsequently standardized by the IEC as IEC 61966-2-1:1999. It is often the “default” color space for images that contain no color space information, especially if the images’ pixels are stored in 8-bit integers per color channel.
Gamma correction, or often simply gamma, is a nonlinear operation used to encode and decode luminance or tristimulus values in video or still image systems. Gamma correction is, in the simplest cases, defined by the following power-law expression:
- {\displaystyle V_{\text{out}}=A{V_{\text{in}}^{\gamma }}}
where the non-negative real input value {\displaystyle V_{\text{in}}} is raised to the power {\displaystyle \gamma }
and multiplied by the constant A, to get the output value {\displaystyle V_{\text{out}}}
. In the common case of A = 1, inputs and outputs are typically in the range 0–1.
A gamma value {\displaystyle \gamma <1} is sometimes called an encoding gamma, and the process of encoding with this compressive power-law nonlinearity is called gamma compression; conversely, a gamma value {\displaystyle \gamma >1}
is called a decoding gamma and the application of the expansive power-law nonlinearity is called gamma expansion.