David Gowers wrote:
Where's a linear encoding? sRGB (ie. the RGB888 encoding used on 99% of standard displays) is encoded nonlinearly with approximately gamma 2.2.
Yes, but image processing operations often ignore that and add RGB components together as though they were linear. You can get away with that because the curve isn't too far from linear with gamma values typically used. However, the purpose of gamma encoding is to correct for nonlinearities in the display device, not in human vision. For the latter, you would need some kind of log scale, and you wouldn't be able to get away with treating the values as linear. Also, the idea of encoding images with some kind of assumed gamma for the display device is becoming less and less sensible as CRTs are disappearing and being replaced with LCDs and other display technologies, which presumably require quite different gamma values. It would be more sensible to encode all images linearly and apply gamma correction in the output hardware.
I think it's also true that there are some RGB101010 displays that can actually display color values outside of standard sRGB
Seems to me that if there is a linear relationship between RGB components and light intensity, then given enough dynamic range, you should be able to represent any colour that a human is capable of seeing, no? -- Greg
