> I would like to extend the topic of colour correction: Having a quite
> simple option for a linear transformation is of course fine in many
> situations, but it is not enough for high quality scans. [OK, the
> following mixes the topics of colour correction and calibration...] Look
> for example into some documents of the ICC
> (http://www.color.org/profiles.html or
> http://www.color.org/iccprofiles.html): The ICC profiles allow for
> non-linear transformations in order to achieve better quality. A quite
> complicated but perhaps useful approach to use ICC profiles within Sane
> qould be a transformation
>
> raw
> scan -----------------> CIELab ------------------------> output
> data mapped using data mapped using an data
> an ICC profile ICC profile for
> for the scanner CRT tubes
> (or whatever)
Nearly all scanners use CCD or CMOS sensors which are inherently linear
devices so there would be no practical need for doing non-linear color
transforms. A 3x3 matrix followed by a tonemap would be good enough.
-- -- Ewald
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