Hi all, I'm writing more platform tests, this time for gamma correction. The whole "display gamma" being condensed into a single number is a thing people cleverer than I have argued about for years, but I have a simple question. If a display is specified as "gamma 2.2", does that mean that the XYZ->Y component follows a 2.2 curve, or has each RGB channel got it's own gamma which is then averaged? If it's an RGB measurement we calculate gamma with, how do we map from XYZ to RGB? Also, what white-point would we use? All the "gamma checker" images decompose this into sRGB gamma, but I'm not sure I get the logic why. For my uncalibrated DreamColor, Y is pretty much exactly 2.2. For my uncalibrated Thinkpad T510, my Y gamma is 2.7. Ouch. Advice welcome, thanks. Richard.