ITU-R BT.1886

ITU-R BT.1886 is the reference EOTF of SDR-TV. It is a gamma 2.4 transfer function considered as a satisfactory approximation of the response characteristic of CRT to electrical signal. It has been standardized by International [Telecommunication Union|ITU] in March 2011. It is used for Rec. 709 and Rec. 2020.

Definition

BT.1886 EOTF is as follows:
where

is the screen luminance, in Candela [per square metre|cd/m²].
is the input video signal level, in the range.
is the exponent of the power function and equal to 2.4
is the variable for user gain
is the variable for user black level lift
is the screen luminance for white, in cd/m².
is the screen luminance for black, in cd/m².

According to ITU, for a better match, can be set to 0.1 for moderate black level settings or to 0 for lower black levels.
An alternative EOTF has also been provided by ITU for the cases a more precise match of CRT characteristics is required.