Color spaces (was DEC Colours)

But not one as simple as CMYK. Quite aside from the ways our eyes respond to light, in order to truly match a given colour, you do need to match its reflectance spectrum at least moderately well, otherwise the goodness of your match will depend on the spectrum of the light you look at it under. (Just because two lights look the same to your eyes does not mean they have even approximately the same spectra! It just means that their spectra dot-producted with your eyes' colour receptors' sensitivity spectra come out fairly close to the same. Or whatever the term corresponding to integral[x](A(x)*B(x)), the continuous analog of a dot product, is; I can't remember offhand.) And then there are issues of specularity and translucency and such. /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse(a)rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B