Hello, Thanks a million times for the information about this and thanks also for the links. I now know more about color calibration and what it means. One lat thing. Should I or shouldn't I upgrade to 10.4.3 then to 10.4.4. Right now X is quite stable on my machine. I'm always a bit anxious about upgrading... Germain iMac G5 / 1.8 mhz / 768 RAM Tiger 10.4.2 français