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[T3D Dr. George A. Themelis <DrT-3d@xxxxxxxxxxxxxxxxxxxxxxxxxxx>]

Sorry, I missed the discussion on Lambertian Surfaces and viewer relectors.
Can someone post a brief summary for me?  What is a Lambertian Surface and
where can I get one?  ;)  

Side topic:  Are you familiar with the late Ted Lambert, a well-known 
stereo photographer, famous for his trick stereo photography?
Do you know that Paul Wing (other well-known stereo photographer) is also
a well-known engineer (retired) in the area of valve construction?  I was
working on a problem involving valves and someone at work gave me this
copy with everything I ever wanted to know about valves.  It was authored
by Paul Wing!  I asked Paul about it and he admitted that this was him!
He wrote about a great 3d presentation he made to a group of engineers
while everybody was drunk!  He said that he commisioned Ted Lambert to
make a few stereo slides for the occassion.  He sent me one that he did
not use in his presentation.  It showed a little plastic figure pointing
to a butterfly pinned in a small model blackboard.  This was introducing
the subject of butterfly valves.

I have been concerned about the light fall off at the ends of a viewer
and was thinking that a cylindrical surface (semicircle seen in projection)
with the bulb at the center, is the geometry needed to avoid light
fall off.  Is this correct?  The reason it was not used in the 50s must
have something to do with having the viewer compact, plus the 5p window
did not utilize all the reflector area.  But now that we open our viewers
to 7p and 8p, light fall-off has become a problem.

George


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