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3D viewing methods:
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Shutter glasses: Although, IMAX 3D movie theatres are now using it for quite a long time, this system is one of the more modern. A device synchronised with the movie shows alternatively one image a t a time to each eye. The frequency of alternation is, in the case of IMAX, of 96 frames per second. So no flashing is seen. In the case of home videos the best rate is 60Hz (in the case of NTSC), witch is equivalent to see the scene at the rate of 30 half images per second so a resulting sensation of 15Hz, frequency slow enough to guaranty headache. Let's not speak of the PAL and SECAM offering to the eyes a show at 12,5 images per second.
In order to permit to each eye to only see its corresponding image, the device (active glasses) hide alternatively one eye synchronically with the screen.
Advantages: Easy to set-up, even on a big screen,, if you have the hiding device.
Disadvantages: Price of the device included actives, so expensive, glasses for each spectator.

Passive glasses with Byatt modulator (Liquid Crystal Color Shutter): In spite of separating the two images with active glasses, a very amazing device can be used: Byatt modulator. It consists of a plate containing liquid crystals with the ability of fast polarisation change upon the action of an electric field. A pair of normal polarised glasses is then required to view the 3D. In 1993, I had the great opportunity to use the CAChe (Computer Assisted CHEmistry) chemical modelling system. The system was composed of a configuration calculator (program running on a IBM RISC 6000 station, no relevant in our case) and a computer, it was a highly powerful Macintosh (probably a 33MHz Quadra 800!) and especially a special graphic board with a "3D Tektornix" screen (as Tektronix was tear apart, the software is now sold by Fujitsu-Siemens and the screen must be the MacNaughton Inc. NuVision according to my Google search).
At that time, I was not a stereo-photo addict but I imagine that same screen in the cellars of my laboratory of that period ; poor fellow how it must be boring! Maybe it is just the memory that makes that system one of the best I ever test to view 3D? Of course I was looking at "MY" molecule. That image is reconstructed with RasMac 2.7.2.1 from the 1993 ".pbd" file resulting of the optimisation with the Tektronix system. the only thing remaining except what I remember.
Advantage to the previous system: Use passive, thus cheap glasses.

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2006 Docteur Christophe