tarlack wrote:as long as there is no fluorescence, incomplete linear color spaces can be used (such as sRGB), but what about fluorescence ? Couldn't this cause out-of-gammut colors to appear ?
Probably yes. But aren't gammuts only of concern for an input and output devices? What matter does it make if the calculations produce out of gammut values during calculations? The real gamut that count is the output gamut. The end result is that those out of gamut calculation values will be clipped when transformed to output color space. But there are little we can do about that.
I see the gammut issue somewhat similar to HDR data being mapped to LDR of the output device. As long as the internal calculations can represent HDR data. I'm good. As long as the internal calculations can represent as much out of gamut values as is required, I feel I'm good too.
Would a complete color space such as XYZ be better for this specific case
I experimented with different color spaces a few years ago, and XYZ turned out to be not too far from the worse color space to use for internal calculations. And I think this is due to the metameric property of XYZ space. The color spaces that produced the best results are spaces based on filtering the spectrum into equal width bands similar to the filters used in digital cameras. If most of your input colors come from digital cameras, then you would be better use the raw RGB data from the camera and an equal spaced 3-bands RGB representation for your internal calculations.