RE: filmscanners: Nikon MF LED light source...

["Austin Franklin" <darkroom@ix.netcom.com>]

> DMax *does* have a particular meaning in photography and it ain't
> 'dynamic range'. It is an absolute value of opacity - a densitometric
> measurement relative only to the illuminant intensity unimpeded by film.

Yes, film and paper can be measured by a calibrated densitometer, but what
you are calling an absolute number is really relative.  It has to be, all
density values are relative to something, it's just that through
calibration, the relationship is "standardized".

This is really different than scanner dynamic range, which is not based on
any standardized point, it is relative only unto it self.

> This is a separate parameter , distinct from Dmin or the dynamic
> range, aka
> Optical Density Range/ODR (difference between DMax and DMin).

Why isn't that the same as dynamic range, if they both are DMax - DMin?  If
ODR was stated as DMax AND DMin (not added, but both parameters stated) that
would be meaningful.

I understand your point that a dynamic range of 3 may have other parameters
of interest associated with it, as in when you are scanning 1-4 vs 0-3, such
as noise.  The dynamic range decreases when noise increases, so I don't know
that I completely agree that the dynamic range ends up being the same for
each...

There certainly are a lot of characterizations I, for one, would like to see
able to be characterized for film scanners.  That's a whole other issue
though.