 The dashed black curve behind the red curve is a standard power-law curve, for comparison.Output to CRT-based television receivers and monitors does not usually require further gamma correction, since the standard video signals that are transmitted or stored in image files incorporate gamma compression that provides a pleasant image after the gamma expansion of the CRT (it is not the exact inverse).For television signals, the actual gamma values are defined by the video standards (NTSC, PAL or SECAM), and are always fixed and well-known values.