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RE: filmscanners: Nikon Scan & VS Negative dynamic range
Tony writes ...
> On Wed, 5 Sep 2001 23:29:34 -0400 Austin Franklin
> (darkroom@ix.netcom.com) wrote:
>
> > Mapping the input data into 8 bit values has nothing to do with the
> > dynamic range of the A/D data
>
> Arrgh... not this again! :-)
>
> Actually it does, ...
> ...
Correct!!! ... "linearity" is the keyword, that is, the scanner's driver
cannot map the CCD to RGB data non-linearily without losing information.
The only method, without losing info, is to map the linear CCD to greater
RGB depth. And if you take a the math a bit further you realize 12bit depth
is all that is required to cover the most extreme optical densities (...
altho there's nothing wrong with having a couple of bits of headroom, as
long as the scanner had a true ability to scan OD=3.3 ...)
shAf :o)
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