Early Stereoscopic 3D Movies
A French audience watching a stereoscopic 3D magic lantern show in 1890. The audience members wore glasses with red and green colored lenses, to correspond with the left and right perspective slides. This is the anaglyph technique, which is commonly implemented for printed material, like picture books or comic books. The coloring effect can be rather distracting from the stereoscopic effect.
A New York audience watching a stereoscopic 3D movie in 1922. All audience members were seated behind rotating mechanical shutters, which alternately revealed left or right perspective frames projected onto the movie screen. This may seem like a clumsy or awkward invention, but it took advantage of the rotating shutter design inherent in motion picture cameras and projectors. Furthermore, this time-based multiplexing technique for alternately transmitting or occluding left and right images is the basis for modern liquid crystal shutter glasses.
The famous Life magazine photo of an audience watching a stereoscopic 3D movie in 1952. By this time, polaroid filters were used for stereoscopic glasses instead of colored filters. Since light can be "polarized" into 2 separately oriented components, complementary polaroid filters can be used for separating left and right perspective frames projected on the screen. The neutral color of a polaroid filter allows for non-distractive viewing of either color or black-and-white stereoscopic movies without the artificial coloring required by anaglyph glasses. The same principles of optical polarization are also used in modern liquid crystal shutter glasses.
(Illustrations reproduced from Amazing 3D by Hal Morgan and Dan Symmes.)