On old 27" iMac, if I open three windows and view the same photo side by side in my photo editor, Safari and Firefox, the same picture appears very close in colour in each window, ie, as they should. On the new (Dec'12) 27" iMac, all three are widely different, in the Photo Processor the original looks slightly more saturated and warmer colours than on the old, in Safari much more so, ie garish, in Firefox colourless and muted. Whilst changing the profile might get rid of the basic warm caste, it would affect each browser equally. (I've tried and it does!) ie Safari remains garish and Ffox very muted. Is this a known colour management issue with 10.8.3?