On Sun, 5 Aug 2001 22:39:35 EDT (RogerMillerPhoto@aol.com) wrote:
> For negatives, I believe it was Ian Lyons who said that calibrating the
> SS4000 and SilverFast with an IT-8 slide also had benefits for
> negatives. I don't know why. But I can certainly see how information
> from an IT-8 slide could be used to characterize the scanner's deviation
> from some norm so that software could improve (make more consistent)
> negative scanning as well. For example, if IT-8 calibration finds that
> the scanner's red channel has a weak response when scanning transparency
> film and then makes an appropriate correction, then it seems the red
> channel gain would have to be boosted just as much when scanning
> negative film in order to get a "normal" scan. This is speculation on
> my part.
Yes. What you are actually achieving via IT8 calibration is a set of
corrections for the CCD's response to a variety of dye densities in
different colours. This remains valid so long as the dye set is close to
that used for calibration. C41 and E6 dyes are the same family, and Fuji
and Kodak E6 are basically similar. Agfa seem to use rather different dyes
(TBH I haven't tried any of their newer films), and Kodachrome is utterly
different.
Regards
Tony Sleep
- Online portfolio & exhibit; + film scanner info
& comparisons
