What do television standards do about gamma?
Since most sensors used in television cameras produce output voltages proportional to scene intensity, a correction for CRT gamma must be applied to the camera signal to avoid having midtones in the scenes being too dark on the TV set. When television standards were defined it was decided to correct for the gamma of the CRT in every television set by using a correction circuit in the camera which applies a gamma of 0.45 = 1/2.2. This value was chosen to simultaneously correct for the CRT gamma of 2.5 and compensate for the apparent reduction of contrast which occurs when a TV is viewed against the dim background typically found in a living room. Applying the correction at the studio was more economical than applying the correction in every TV set.
