[JMac]

I believe color numbers should be lighting dependent, which is different for everyone. I was working in a classroom for awhile that had white walls and bright, glossy floors lit by natural light mixed with fluorescent lighting, and successfully calibrated. We had trouble tracking color, however. I moved to a hall with less fluorescent light, added halogen lighting, and used a darker grey color for my backgrounds. Again, I successfully calibrated, and this time I could track all the colors. However, the numbers were all significantly different than before. Maybe this was just my setup being quirky, but as I understand it, lighting determines both the ability to calibrate, and the numbers that calibration gives you.