sharky
This is how I understand it:
even if CCDs are linear, you still have two problems:
...
Al this mapping stuff can be done with 'dcraw'.
That's how I understand it, too.
igvk
Experience tells that color reproduction with only linear transformation could be wrong, and often is. This way, photos will be looking unprofessional, or unpleasant to the eye, I suppose.
Of course, color reproduction could be wrong with a color matrix, as it could be with a full profile of any complexity (I'm not a color expert, but I believe that the main part of a profile is the color transfer curves, which for a linear detector should be straight lines). And surely, color transformation does not need to be linear -- after all, the "quality" of the result is judged subjectively by eye. But, whatever the color transformation, one first needs to know the color sensitivity of the sensor, for instance in the form of a color matrix that determines how to transform a color from camera sensor color space to device-independent CIEXYZ space,
for different lighting conditions. The best one would like to know is the sensor spectral response, i.e. R, G, B sensitivities as functions of wavelength, from which everything else follows -- and which is something that Canon designers surely have at hand.
Now, talking about the users around here, who are not Canon designers, then at the moment there's nothing for your camera -- no color matrix, no ICC profiles, no nothing. ArtDen's method in dng4ps2 can only provide an approximation that is often unsatisfactory, as seen above. Obviously, to obtain an accurate color profile, one
needs some kind of calibrated input, which brings us back to color targets, etc. Well, white balance could be obtained with a white/gray card, but that's not enough of course.
Edit: Some WB-related data (+ some unknown color related data) can be obtained from propcase 100/269 (propset 1/2), as Ewavr discovered some time back. But these WB values are rather odd, at least in my case, and are changing even when WB is not set to auto. Obviously, something for Canon internal consumption, not for outsiders...
