Digital Video and HD

What Hacker News says

1. gabeskJul 2021
   Charles Poynton has good references on this. His website is very 90s, but his books (a la Digital Video and HD) are the best clearly explained introduction to color science and gamma vs linear light coding that I've ever read.

   https://www.poynton.ca/Poynton-color.html

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2. raphlinusJan 2020
   I have actually seen a lot of different explanations why the sRGB EOTF has a linear part, and can come up with a few more theories myself. In the Poynton FAQ, it says it "minimizes the effect of sensor noise in practical cameras and scanners". Wikipedia says "The purpose of the linear section is so the curve does not have an infinite slope at zero, which could cause numerical problems." Poynton's book Digital Video and HD: Algorithms and Interfaces talks about "veiling glare" and then says that the sRGB function almost perfectly inverts L* from the CIELAB color space (a pure 2.2 gamma would not do so). His thesis[1] goes into more detail.

   One possible theory why there's a linear term is so that negative values are well-defined. In consumer HDMI, reference black is 10 (as opposed to 0 in sRGB), and reference white is 235 (as opposed to 255 in sRGB).

   Since there no doubt be experts here, I'd love to see an authoritative answer. (I'm considering writing an explanation of sRGB and if so would really like to get this right)

   [1]: http://poynton.ca/PDFs/Poynton-2018-PhD.pdf

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