Audience at a Three-Dimensional Film

In the 1950s three-dimensional (3-D) films enjoyed a brief period of popularity. The illusion of three dimensions on a flat screen is created by projecting two separate movies—one made for the right eye, the other for the left. Members of the audience wear 3-D eyeglasses so that the right eye sees one picture and the left eye sees the other, producing the effect of three dimensions.

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The development of the Polaroid system of filming by American inventor Edwin Herbert Land made color 3-D movies a reality. Films made using this method are shot with two cameras or a special camera with two lenses. In the theater, the two films are projected simultaneously. A polarizing filter in front of the left projector lens orients random light waves into one plane, while a different filter in front of the right projector lens orients light waves into a perpendicular plane (see Optics). Filmgoers wear glasses with gray polarizing lenses that orient light waves in the same way as the filters on the projectors. This causes the viewer’s left eye to see only the image from the left projector and the viewer’s right eye to see only the image from the right projector. The brain receives these two separate images and fuses them into one 3-D image.

The first polarized film was demonstrated in 1939 at the New York World’s Fair. In the 1950s, attendance at polarized 3-D movies soared. Between 1952 and 1955, over 110 features, shorts, and cartoons were produced in 3-D. These included the classics House of Wax (1953), It Came From Outer Space (1953), Kiss Me, Kate (1953), Hondo (1953), Creature from the Black Lagoon (1954), and Revenge of the Creature (1955). The 1950s also marked a high point for 3-D still images. In addition to films, 3-D images appeared in comic books, newspapers and magazines, posters, jigsaw puzzles, and greeting cards. The polarized film process lives on in today’s state-of-the-art 3-D movies in theme parks, as well as some IMAX 3-D theaters. IMAX 3-D movies project giant images on screens seven stories tall, giving viewers the impression that they are submersed in the scenes projected on the screen.

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AUTOSTEREOGRAMS

An autostereogram is a stereoscopic image that does not require special viewing devices, such as a stereoscope or 3-D glasses. Among the most popular types of autostereograms are lenticular images, holograms, and computer-generated single image random dot stereograms (SIRDS).

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Lenticular Images

A lenticular 3-D image is a composite of two source images of the same object viewed from slightly different angles. The source images are sliced into extremely narrow strips and merged, or interlaced, then covered with a plastic screen consisting of thousands of tiny ridges and grooves. The ridges and grooves, or lenticules, act as lenses, directing the left source image to the viewer’s left eye and the right source image to the viewer’s right eye. The brain receives the two separate images and integrates them into a single, 3-D image.

Lenticular technology was especially popular in the 1960s, when it was used to create 3-D images of religious scenes and souvenir postcards. The technology is also used to create a sense of motion in flat images. This is achieved by interlacing a sequence of photographs of a moving object. The composite image is covered with a plastic lenticular screen, which delivers each source image to the eye individually as the viewer changes the viewing angle of the composite image.

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Holograms