ghosting and seashell x-rays

[P3D Michael Kersenbrock <michaelk@xxxxxxxxxxxxxxxxxx>]

Greetings,

	Just a comment to you regarding Peter's x-ray photos of
seashells that he showed at NSA '97.

	Although Peter's projected images were very good at NSA '97 and
privately projected images being perhaps better, looking at his
images through a realist red-button viewer are spectacularly
more impressive.  I think it's obvious to anyone seeing his slides
with the viewer.

	The probable reason is dynamic range.  His images were mostly
black with white images sometimes very bright and mostly just a whisper
of light.  It's the type of image that can make any ghosting very visible,
but I think the biggest projection loss in Peter's images is the loss of 
dynamic range, in particular, on the low-light-end.  A great deal of his
images are the thin portions of the shell and that's almost completely missing
when projected -- either due to residual light level in the room (projection
light leaks, secondary relections, etc) and/or lower image brightness.

	Various techniques have been mentioned about how to improve 
(reduce) ghosting problems.  What else can practically be done to improve
dynamic range -- other than the obvious (like brighter bulbs and keeping
down light from the outside).  Can the slides be practically copied to compress 
the dynamic range after-the-fact in a controlled fashion?

	His slides when viewer viewed are VERY impressive!

Mike K.


P.S. - I don't mean to deflect focus on ghosting.  Indeed, ghosting may be
       a major player in the reduction of dynamic range when projecting.


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