P3D Re: it is a question of projection

[Oliver Dean <3d-image@xxxxxxxxxxxxxx>]

Lincoln Kamm wrote:

> Thanks for all of the advice.  What about the realist projector?  It is
> certainly (in my opinion) the coolest looking projector.

I had the use of a Realist projector for a short while.  It was sturdy
(except for the case bottom, which was made of easily broken bakelite),
had sharp optics, and was bright (twin 1000 Watt lamps -- a problem for
15 Amp circuit breakers; 20 Amp circuit is usually required). But the
cooling system was very noisy and the lens focal lengths were only 3",
which usually put the projector too close to the screen, where it
blocked the view from those valuable center seats in a large audience.  

Furthermore, the tricky rotary slide carrier was a problem in that it
did not position slides with consistant vertical alignment. You put the
slide in the carrier in viewer position (thumbspot at the lower left),
and rotated the carrier 180 degrees to put the slide in projection
position. Because the mechanism to stop the rotation was not precise,
the slide could be rotated too far or not quite far enough, thereby
resulting in vertical misalignment.  

Vertical and horizontal alignment knobs were in an idiotic position in
the front of the projector and very close to the lenses, making it
extremely difficult for the operator to make adjustments without getting
his hand in front of the lenses!  

It may have looked cool, but I would recommend staying away from it
unless you have a lot of money to spend and want one as a second
projector for occasional projection in close quarters or for a
collection. It was a beautiful kluge!

> What would be a fair price for the tdc 116 projector with 4" or 5"
> lenses in good condition?

At one time I would have said $200 - $350, but prices have changed a lot
recently. Others can advise you better on this.  You might want to check
<http://www.bpwltd.com/>, which is run by Brian P. Wolfe, the same
person who operates the Buena Park Camera Show, and see what his current
prices are; his prices may be a bit higher than what you might find
through a private sale, however.  Also, I don't have to tell you to
check the Stereo Club of Southern California Auction next month
(October)!  There will be at least one TDC for sale there, but I don't
know which model. 
 
> 
> Has anyone here tried to do any rear screen projection?  If so, what is
> it that you projected onto?

For rear projection with his one-of-a-kind Spindler and Sauppe stereo
projector, the late Stergis M. Stergis had a translucent matte plastic
material that he found, after a lot of research and testing, that
allowed rear projection without depolarizing and, what was REALLY
remarkable, without showing a "hot spot" at the place where the
projector lenses would be visible if the material were more
transparent.  Unfortunately, the secret died with him.  His widow, Maude
Stergis, might have some clues as to where he got it or what it was, but
don't get your hopes up.  The screen he made still exists, but when I
last saw it about a year ago it looked as though it might now be
somewhat discolored and might not work well any more (it may simply need
cleaning).  

Ground glass can work passably, but doesn't transport conveniently and
usually shows a hot spot.

Cordially,
Oliver Dean