ITU-R BT.1886 is the reference EOTF of SDR-TV.
It is a gamma 2.4 transfer function (a power law with a 2.4 exponent) considered as a satisfactory approximation of the response characteristic of CRT to electrical signal.
It has been standardized by ITU in March 2011.
can be set to 0.1 for moderate black level settings (e.g. 0.1 cd/m2) or to 0 for lower black levels (e.g. 0.01 cd/m2).
[1] An alternative EOTF has also been provided by ITU for the cases a more precise match of CRT characteristics is required.