Stereo Projectors
Stereo
projection has never been a simple matter. As with any form of stereo viewing,
the process only works if each eye is presented its own specific image.
Projection may be accomplished through the anaglyphic (red/green) process,
but color slides have to be converted for use and much of the color
information is lost. Quality stereo projection relies on polarizing
the transmitted light. Each image is passed through a polarizing filter.
Filters for left and right are rotated 90 degrees out of synch. By wearing
a pair of glasses with corresponding filter angles. The light from the
left image is excluded from the right eye and vice versa. If you take
the glasses off and look at the screen, you will see two confusing overlapping
images. The process works well, but requires a lenticular projection
screen. A white screen or wall scrambles the light and polarization
is lost. For projection, accurate alignment of the two images in the
mount is critical. You can give your audience headaches in no time while
adjusting each individual projected pair. As we enter a new era of 3D imaging, LCD shutter glass technology is about to find a home on the TV in your living room, but this is an unlikely method for projection. |
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Systéme de Projection Anaglyphique The first truly bright, controllable light source was limelight, a term still in use today long after it's original namesake has become obsolete. Although invented before |
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Gaumont Anaglyph Projector attachment Strictly speaking, this is not a dedicated projector, but rather a conversion kit which transformed a Gaumont Stereodrome cabinet stereo viewer into an anaglyph stereo projector. A special set of projection lenses replaced the normal viewing lenses, and an electric light unit was inserted into the back of the viewer. The pair of 55 watt bulbs could only have produced a rather dim image on screen. Because the red/blue filter is a drop in on the front of the projection unit, it would be possible to today to substitute polarizing filters - if one were crazy enough to actually try using the system. The shiny round thing on top is a giant rheostat, and the gauge is a volt meter with a red mark at 100 volts. |
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Richard Projecteur Stereoscopique "Le Moulinex," so nicknamed for its resemblance to an old French made hair dryer, was never sold in significant numbers. It was a very expensive piece, and other equally capable projectors could be had for a lot less money. The projector was sold with carriers for multiple formats, including the then current Verascope F40's 7 perf European format, and 45 x 107. An interesting feature of the Richard are the two black forward pointing knobs next to the lenses. These are used like gear levers to adjust for convergence and elevation. Each shaft is anchored behind its lens. A ball socket in the lens mount surrounding the lever causes the lens to slide around as the lever is manipulated. It would be fun to try it out, but the power cords are a little frayed and it needs 220 volts. No doubt it it would have the ubiquitous 1950s era fan noise from hell.
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Realist 81/82 I am not generally in the habit of naming inanimate objects, but within seconds of firing up the Realist it became known as Darth Vader. It both looks and sounds like the movie villain. A classic example of engineers run amok, everything about this machine is complex and goofy. To change images, a handle at the back is pulled down. This is then translated into into rotational motion in the two position slide holder located in the center of the machine. If you don't pull the handle with the right amount of force, it will be necessary to manually click the carriage into its final position. Slides are fed one at a time and the operator must continually maneuver around the machine to deal with focus, tilt, convergence and slide changing controls. Not surprisingly, Realist projectors are rare today, but may be considered highly desirable collectibles. "Luke, I am your father..." |
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TDC 716 Stereo Vivid Deluxe Stepping in where David White feared to tread, the Three Dimension Corporation produced a far more practical projection system. The 116 model used 500 watt bulbs, and the 716 used 750 watt bulbs. With polarization, light output is subdued, so the higher wattage bulbs are a welcome feature. The Selectron unit mounted on the projector used 30 image trays and allowed the operator to simply slide views in and out of the projector, then click a rack and pinion wheel to advance the tray. Though more ergonomic for the projectionist, at 1500 watts it was still a sweaty job for the projectionist, who worked in close proximity to what amounted to an effective space heater. Like the Realist, the fan is rather loud. |
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Belplascus V Produced to compliment the Belplasca stereo camera, the Belplascus is a simple projector of limited features. It was, however, designed to project the wider 7 perf European format slides produced by the Belplasca camera. As its wired for 220v I have never bothered to try it out. Like all stereo projectors, I'm sure it takes some tinkering to get images properly aligned on screen. |
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Diatom 100 Produced by Hermann Schneider & Co of Hamburg, the Diatom was a small and simple projector. Polarizing filters are mounted outside the body of the unit, in front of the lenses. You now know as much about it as I do. |
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Projector, Aerial Roll Film Continuous Strip-Type F-2 Suffice it to say, this is not a commercial device. If it were, it would be named something like "Le Monstre Projecteur de Stereo." It's big, and heavy, and looks like an early '50s Cadillac. Probably consumed a similar quantity of natural resources to operate as well. When in October of 1961 an American U2 spy plane spotted nuclear tipped ballistic missiles in Cuba, a call went out for detailed low level photographs of the missile installations. Low level over flights would have to be accomplished at high speeds, and normal surveillance cameras of the day were not designed for this mission. The Air Force consulted with General Goddard, who although technically retired, was still one the premier experts on aerial photography. He recommended using a stereo strip camera. The principals of strip cameras were well known at that point, but the USAF had previously retired all their strip cameras. A call went out, and examples of the Fairchild KA-18a stereo strip camera were found in storage at Wright Patterson. At least one of these cameras was quickly mounted in the nose of an RF-101A Voodoo aircraft, and high speed, low level reconnaissance flights were made over Cuba. The projector presented here was designed to project the 70mm stereo film strips produced by this camera. How many of these beasts were made, who knows? This one is serial number 34. There cannot have been a lot of them. Could it have been used during the missile crisis. Certainly there is a chance, but no way of ever proving it. The only reference I have ever found regarding this projector is the title of a mil spec document declaring the projector obsolete some time in 1960. The cameras had been officially retired by this time as well, so both cameras and projectors could have been briefly put back into service. |
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RBT 101 The same folks who build modern stereo cameras also build a modern stereo projector. Incorporating features such as zoom lenses and remote control operation, the 101 eases stereo projection to the extent possible. The Germans must equate mass with quality. For reasons I cannot possibly explain, it weighs a ton. There is a story the unit was originally a Kodak design project. It seems reasonable in as much as engineering a complicated device of this ilk would be a major challenge for a company as small as RBT. |