> Nothing useful shifts colors by a fixed offset in either XYZ or L*a*b* > or any other typical color space. Typically shifting a white point > involves moving all the other colors in a way that has most effect > for colors with a similar Y/L*, and proportionally less as you > get close to black, the details depending on what space it is done > in, and whether there is a chromatic adaption matrix involved, etc. Hi Graeme, My English is sloppy. What I really meant is that the gray lines are brought into line (so to speak) ... so (normally) there will be a greater shift at the white point, less at the middle gray and least at the black point. But at a particular luminance level, are not all colors shifted by the same amount in an Absolute Colorimetric transform? I take it that this is what you said above? I don't know what a chromatic adaptation matrix does, or how it is produced. Are you talking about the illuminant and FWA compensations? If so, is there a separate mapping matrix (as you imply) or is the compensation built in to the table? If you know of any really good literature on this whole subject (which would be comprehensible to someone without a background in color theory) I would be very grateful for the reference. I do have an engineering degree so I can cope with a certain amount of maths, but preferably not too much! I really hate asking silly questions that take up your time and the time of others, but I've found it very difficult to find fairly in-depth and at the same time correct information. Going to the ICC is just way too much for me. Thanks Robert