[filmscanners] Re: HP PhotsSmart - questions

["" <wbgilloolyjr@charter.net>]

Anti-reflection coating on the flatbed of a scanner has nothing to do
with uncovered parts of the flatbed and everything to do with the fact
that anytime the image forming light hits a glass-air surface there is
the potential for a reflection (or backscatter) which will reduce the
contrast of the image (non image-forming light hitting the unexposed
parts of the CCD/CMOS).  Any time you have light passing across a
glass-air surface you will improve image quality (particularly contrast)
by AR coating the glass.

Mr. Bill


Laurie Solomon wrote:
> Art, I have never run across this either; but I think that both you and
> I have used mostly lower and middle end units.  It may be very possible
> that the very high end commercial flatbed scanners might employ such a
> coating - particularly if they are large commercial wide format scanners
> and there is a significant possibility that there will be times when the
> originals to be scanned will not cover a significantly large portion of
> the glass flatbed so as to allow for potential reflections of the
> uncovered glass portions of the bed if a non-reflective coating was not
> used.  Of course, this is just speculation on my part since I cannot
> afford any of those models. :-)

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