Originally Posted by sotti
BT.1886 always includes a black offset so it's never just 2.4
If one is trying to match a CRT operated at low black level the recommendation states:
"For moderate black level settings, e.g. 0.1 cd/m2, setting the LB of the EOTF to 0.1 will give a satisfactory match to the CRT. In the event the CRT is operated at a lower black level, e.g. 0.01 cd/m2, the EOTF will provide a better match with LB set to a lower value such as 0.0 cd/m2
So it really depends on what EOTF you assume the material was mastered on, in combination with your display abilities.