Light displayed on computer monitors are not linear, instead follow a power law transformation, also known (less precisely) as a non-linear transfer function. P

Light displayed on computer monitors are not linear, instead follow a power law transformation, also known (less precisely) as a non-linear transfer function. Pixels should only be stored in gamma (non-linear) space for final display; all math on them should be performed in linear space instead. sRGB has a badly defined gamma space of an encoding of { [0-15] (linear), [16-255] (power of 2.4 over [0-239] with an offset of 16) } with a decoding of 2.2 (but explicitly taking into account "dark room" ambient lighting, not the actual display response). This is often quoted as "power of 2.2 encoding and decoding", and this has never been correct. For modern viewing conditions with a 100 nits monitor in an ambient condition of "bright room", the proper interpretation of sRGB is to read as "actual monitor response of 2.4", which leads to.... bt1886 defines this as 2.4 encoding combined with a 2.2 and 2.4 decoding where the crossover point is calculated in a way that takes into account actual black levels observed on the device to maintain perceptual quality while avoiding black and white crush (devices with actually zero black (ex: CRT, Plasma, OLED) would just be pure 2.4 decoding). This allows all commercial content (NTSC, PAL, and BT709/BT2020) to display favorably no matter how badly it was mastered originally and no matter how bad the viewing conditions actually are. BBC, taking into account "ye average display over the past 30 years", encodes as 2.35 to take into account NTSC, PAL, 2.2, 2.4, and actually-sRGB displays. This is arguably the most correct approach: bt1886 and sRGB/bt709 on displays that are too dark will be too dark but perceptually correct on displays that are too bright; "encode as 2.2" (which is still wrong) will be very dark on every display; 2.35 will look correct on "wrong, but too dark", "wrong, but too light", "actually sRGB", and "actually bt1886" monitors. There also is a third (fourth?) standard of 2.6 that is purely found in extremely low display light (40 nits or less), zero ambient completely blacked out conditions, used for movie theatres, due to perceptual changes in human eyesight; sRGB, bt1886, and 2.35 would all be too dark and/or too undersaturated here otherwise.