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For
over a half a century, passive polarized glasses have provided the highest
quality projected stereoscopic 3-D images. These replaced the
inferior bi-colored anaglyph type viewing glasses popular in the 1930's
and 1940's. Passive polarized glasses were used to view a stereoscopic
3-D film at the World's Fair in 1939, and by the early 1950's had become
universal. Contrary to popular belief, almost ALL stereoscopic
3-D theatrical feature films, cartoons, and short subjects were exhibited
in the 1950's using passive polarized glasses, NOT bi-colored anaglyph.
Probably the least often recognized effect of polarized material is the unusual form of color distortion. In terms of the visual impression, this color distortion is not so much a shift in hue, as it is a shift in saturation. Warm colors tend to look more or less desaturated. For example, in live action films, actor's faces tend to look grayed rather then the ruddy impression we are used to seeing in color films. This still holds true with digital projection. Some compensation is possible during acquisition, especially with the control made possible on the preview monitors as well as during post. One technique is to view the monitor through two overlaid pair of passive polarized glasses during the color-balancing phase. The reason for two pair, is to simulate both filters used during projection: the ones in front of the projector(s), and the ones worn by the audience. A ramped increase in saturation as the colors approach red can be very useful. |