Am 07.06.2010 04:29, schrieb Graeme Gill: > It would be interesting to see if non-Luther condition cameras > routinely produce such imaginary XYZ values for highly saturated > source colors. If so, then the ICC's advice to clip such colors is > probably not so good... Well, Graeme, it's actually not the camera which produces XYZ values outside the visual gamut (including negative ones), but eventually it is always the matrix. If the Luther condition is met, then there exists (in the ideal case) indeed a single "correct" matrix which is entirely determined by the camera, but if the Luther condition is not met, then the choice of the matrix is is a trade-off between several objectives and evils anyway, and it is no longer the camera only, which determines the matrix. It would be for instance certainly possibly to constrain the matrix in order to avoid that any RGB triples inside the camera's spectrum locus map to XYZ numbers outside the visual gamut - then we should never end up with imaginary XYZ values, even if the captured scene contains the most saturated colors one can imagine (i.e. monochromatic ones). Regards, Gerhard