[filmscanners] cold heads and condensers

["HPA" <tom@historicphotoarchive.com>]

I have long been a fine art printer for other photographers and museums, and
printed on cold heads and condensers for many years (Leitz, Omega, Aristo
etc, five enlarger darkroom for one person), and have read every one of
Ansel Adams and Fred Pickers books and many magazine articles, and am very
familiar with the effects of both light sources, which have only been
partially summarized in the discussions on this group.

A big consideration are scratches on the base side of the film.  These
appear minimally on diffuse light sources.  By comparison, condenser (known
as collimated) light exaggerates minor scratches.

I scan older slides, which invariably show handling marks.  ICE does not
help Kodachrome, Anscochrome, or B&W.

Condenser and diffuse light sources cannot be directly compared because you
have to move the negative from enlarger to enlarger.  Alignment, quality of
the specific lens (even if identical models), flatness of negative carrier,
focus, and negative movement due to heat vary from enlarger to enlarger.  If
you go out and get ten identical lenses, you will find that two are
outstanding, a couple are clearly less sharp, and the rest are in the
middle.

diffuse light sources create more fog in the negative to lens chamber (in
the bellows) and this can appear to reduce sharpness.  Fog is huge problem
in scanners.  I have black tape to reduce it.

If you are scanning only brand new E-6 slide and color negs, especially
batch scanning, the Nikon scanner may be the best choice.  If you are
working on old back files, the Polaroid will run circles around the Nikon.

If you are not happy with the sharpness of the Polaroid, go get Vuescan.
You will get sharper scans and more shadow detail than Silverfast or
Polaroid's program. (IMHO)

Good luck
Thomas Robinson

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