Per Nordlund wrote: > I used -f D50M2 as > FWA compensation. Is there any difference using only M2? Hi, FWA compensation works by adjusting your profile measurements to match your viewing conditions, so by choosing an M2 condition, you are assuming that your viewing environment is UV poor. There shouldn't be a difference between -f D50M2 and -f M2, but note that neither of these options are accurate in calculating a good visual result - they are just there to allow comparison to other measurements made under M2 conditions. This is because the measurements are D50M2 but the XYZ calculation uses D50, a situation not perfectly consistent with the real world. If your viewing environment is UV poor, then it is better to use -f -i D50M2, so that both the measurement and XYZ calculation use the same illuminant. In practice I guess there may not be a huge difference between -f M2 and -f -i M2, but they are different. Graeme Gill.