The Intensity Scale (sometimes called the Gray Scale) not only controls the Image Contrast within all displayed images but it also controls how the Red, Green and Blue primary colors mix to produce all of the on-screen colors. The steeper the Intensity Scale the greater the on-screen image contrast and the higher the saturation of all displayed color mixtures.
Intensity Scale Accuracy
Logarithmic Intensity Scale
Variation with Average Picture Level APL
For the Galaxy S20 Ultra there is only a very small Shift in the Intensity Scales with APL, with the Gamma varying from 2.17 for Low APL to 2.20 for 50% APL. As a result, the Image Contrast appears unchanged with with changing APL, and we then expect the Absolute Color Accuracy to also have small variations with APL, which is examined in Figure 4.
Gamma is 2.17 for Low APL and 2.20 for 50% APL.