BTW, raw files of those images Erik used are available here, along with others.
TCv3100 Hightail link
The last file is a legend in excel.
Thank you David. I took the ColorChecker files for the Trichromatic and Standard Back IQ3-100 and, under the assumption that lighting is about D65 (RawTherapee says about 6480k for the Standard Back) I estimated compromise matrices for them based on average
BabelColor spectral reflectance. There are a large number of provisos and non idealities - lighting, different ISO and exposure, position of cc24 (probably resulting in contamination of some of the patches by reflectance from items in the scene), absence of direct spectral measurements, etc. - not least of which the fact that I am not a (color) scientist and often prone to embarrassing mistakes (:-) so I would take these results with a pinch of salt. Nevertheless I think that they start to give a relative idea of some of the differences in the CFAs in the two backs.
Interestingly, with the assumptions above, the Standard Back is able to achieve better dE and dE2000: SMI is an excellent 86.7, average dE2000 is 1.49, 10 patches have dE2000 less than 1 and only 5 greater than 2. In these conditions this is very good:
The same values for the Trichromatic are: a decent SMI of 81.1, average dE2000 of 1.87, 8 patches less than 1 dE2000 and 11 patches above 2 ( Recall that 1 dE2000 is supposed to represent a just noticeable difference). Decent, but at first glance the SB is more accurate than the TC (shown below):
A strong hint as to what has been changed is given by the CameraNeutral values, that show that the R and B channels are more sensitive relative to G in the TC (an alternative interpretation could be that G is less sensitive, I didn't check it). The wbRaw->XYZD65 matrices suggest that the TC is a little better at blues but the SB is a little better at reds. The weighted sum of RGB negative coefficients suggests that the TC should have a slight advantage with noise but given the large number of differences in the setup I wouldn't put much weight on it.
Finally, here is a screen capture with the two images rendered via their relative wbRaw->sRGB matrix and nothing else, just to show that they work - I did not try particularly hard to match their brightnesses (332, left, is TC; 336, right, is SB):
And each of them individually (which is which?)*:
Jack
PS Information
here may be helpful in understanding the procedure I followed to generate what's above.
* SB first, TC second.