I use a late 2009 27” iMac w 10.9.3 Mavericks. Normally I use “iMac” color profile. I don’t bother with color profiles for my iMac, but today I opened up the Display System Preference. I chose to create a custom monitor profile using the expert mode. Tell me if I am doing this wrong, but I squint my eyes to see the background and foreground apple match, adjusting the handles as I go. I do this for all apple calibration windows, then select slightly less of target gamma than 1.8, then use native white point. Save and assign. But the screen seems to have too much contrast afterwards. I did just as the calibration windows asked by matching the apple and background. Using slightly less than target gamma and native white point. My question is, why does a default “iMac” Profile appear to be better for viewing than a custom profile made w expert mode? John R