What is Gamma?
Gamma refers to the relationship between video signal and light output. A gamma of 1.0 (linear) would mean that an increase of 2x in signal would have a 2x increase in light output. However, most displays have a gamma of between 2.0 and 2.4.
• For video mastering, gamma 2.4 was standardized in ITU-R BT.1886.
• For theatrical mastering, gamma 2.6 was standardized by DCI.
For HDR, a new 'gamma' was introduced called PQ and standardized as SMPTE ST.2084 (see article "What is PQ?").