On Tue, 28 Feb 2006 15:15:45 -0800, David Nebenzahl
wrote:


How can you not "buy" that? That's exactly what happens. It's obvious
and needs no explanation.


And what hadn't occured to me -- till I thought
about it -- is that the illumination from the
scanner is *attenuated* twice. As opposed to the
light from a proper TPA, which passes through
the film once.

So... two reasons for the poor result. First,
the two passes through the film, and second,
a large loss in having to reflect off the white
backing on scanner lid.

FWIW: I repeated the experiment on a Lexmark
X6170 MFP, and results were much the same.


rafe b
www.terrapinphoto.com