Quote Originally Posted by Sasquatchian View Post
Well, I know that there are three color filters after the splitter and before the PMT's, so my guess is that the ultimate gamut of the scanner is defined by those filters.
IMHO, not at all.

The ultimate gamut is defined by the spectral responses (r, g and b) from the particular film we use (or from the dyes on DSLR pixels). The image capture is the critical step.


You can match the "ultimate gamut" of two scanners by a well done calibration procedure, if you use a 3D LUT for that you can get a perfectly matching result, even in the case that the fiters in the scanner are substantially different, you only need a different calibration for each film to equal result from different scanners.

...but you won't be able to make a "general calibration" to match Velvia with Ektar or Portra, because it won't work when spectral nature of light or subject changes.


After image capture you have spectral color information of each spot reduced to 3 values, it can be 3 voltage levels in a sensor or 3 silver density levels after first developer. In the taking we define the ultimate gamut, while the scanning/edition is irrelevant for the ultimate gamut if we have the good software tools.


There is advanced math demonstrating that.


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Scanners are IT8 calibrated, but different scanners may require a 3D LUT calibration for each film for a perfect match.