Ben Goren wrote: > Again, empirically, the synthetic D50 white patch I manually added does > exactly that: > > 1.000000 1.000000 1.000000 [RGB] -> Lut -> 100.000000 0.000090 -0.000032 > [Lab] 0.999999 > 0.999999 0.999999 [RGB] -> Lut -> 99.999950 0.000090 -0.000047 [Lab] 0.999999 > 1.000000 > 1.000000 [RGB] -> Lut -> 99.999998 -0.000105 -0.000068 [Lab] 1.000000 > 0.999999 1.000000 > [RGB] -> Lut -> 99.999939 0.000352 -0.000205 [Lab] 1.000000 1.000000 0.999999 > [RGB] -> > Lut -> 100.000000 0.000006 0.000164 [Lab] > > That seems to me to show the maximum possible preservation of highlights > without > compromising the white point, which I should think is the exact desired > outcome. Hello Ben, I think there is a conflict in intent here. My intent in writing colprof is for it to faithfully represent the devices behaviour. The intent of extrapolation is to estimate the devices response as if it had been characterised with a test chart that fully exercised its gamut. Your intent seems to be to create a profile that gives you the visual output in clipped areas that is most pleasing. If the profile had multiple cLUT tables (one for each intent), then it might be possible to simultaneously accommodate these different aims, but I am a bit dubious as to the utility of this. It seems to me to be a very special situation in photography where a pre-set white point cooked into a profile is going to be right for more than one situation. In general I would have thought that each photo needs to be assessed and it's white point chosen to suite that photo, and the software used to do this is then able to treat (ie. clip) values beyond the white point in an appropriate manner. Graeme.