WHEN THE HOLOGRAM of Princess Leia, projected by the little droid R2-D2, appeared in the first Star Wars movie in 1977, the hopes and dreams of 3D-viewing enthusiasts likely soared. Even though the hologram was fictional, it was a glimpse of 3D’s supposed glasses-free future—never mind that the hologram itself was viewable only in 2D (later plans to reproduce the Star Wars films in 3D fell flat after just one remake). At the time, the typical way to view images in 3D was with cardboard-stock anaglyph glasses—the type with different-colored lenses: one red, the other green, cyan, or blue.
The problem in 1977 was that 3D glasses were utterly useless other than in theaters and with specially produced movies. (This is still true today despite past attempts to sell 3D TVs and an increase in 3D video games.) Of course, in the 1970s, multicolored shades might have jived with bell-bottoms and beads, but the glasses’ effect would have triggered a headache in bright sunshine. That’s because the lenses would interfere with what our eyes and brain already know how to do—see the world three-dimensionally, or stereoscopically.
Still, as longtime Popular Science contributor Walter E. Burton explained in a July 1954 do-it-yourself story that described how to reuse these single-use items, discardable 3D viewers can offer “lots of entertainment value” even after the movie ends. Burton’s instructions were timely. Interest in 3D films was surging in the 1950s—so much so that the decade has since been referred to as the golden age of 3D cinema. After the 1950s, enthusiasm waned, experiencing brief resurgences in the early 1980s and 2010s, the latter inspired by James Cameron’s 3D release of Avatar. But between 1952 and 1954 (when the Popular Science tutorial was published), Hollywood released more than fifty 3D films, including Westerns like Devil’s Canyon (1953), monster movies like The Creature from the Black Lagoon (1954), and the popular horror film House of Wax (1953) starring Vincent Price. By 1954, spare 3D viewers would have been easy for DIYers to come by.
Today we associate 3D viewers with movies, but they actually got their start nearly two centuries ago, in 1838, when British scientist Charles Wheatstone debuted his stereoscope—a cumbersome tabletop contraption that rendered 2D drawings (photography was still in its infancy) in 3D. The first portable 3D viewer was invented several years later by another British scientist, David Brewster; his device resembled a clunky version of the View-Master that debuted at the New York World’s Fair in 1939 and soon became a popular children’s toy that is still available today. It would be another century after Brewster, however, before 3D viewing made it into motion pictures in earnest. Before 1952, only one major 3D movie had been produced—a black-and-white silent movie, The Power of Love, in 1922.
To create a 3D illusion on a 2D screen, the goal is to mimic what occurs naturally in the brain. Researchers are still working out the biological mechanism that enables us to perceive depth, but it’s based on the different views from our eyes, or binocular disparity. When the brain assembles the separate 2D images, it interprets them as one image with depth.
The cover of the July 1954 issue featured a ride-along “kite” and an introduction to color TVs. Popular Science
The effect is reproduced in a theater by slightly offset simultaneous projections. For movies that rely on polarized eyewear, the projected images use polarized light. Light is an electromagnetic wave that travels primarily along two planes—vertical and horizontal. A polarized filter, or lens, blocks one of the planes, or phases. In polarized glasses, one lens blocks the vertical phase, the other the horizontal. As Burton explains in his 1954 instructions, “The two polarizers are set at right angles to each other. Cut the viewer apart, place one eyepiece in front of the other, and you’ll find that little or no light gets through.”
Light also travels in a spectrum of colors—remember ROYGBIV? For anaglyph 3D, the dual images are projected using colored filters so each image is viewable only through its matching lens (red filters will project red images viewable by the red lens, likewise for the other filter lens, which can be cyan, green, or blue), creating the same illusion of depth that our brains achieve on their own. The most common anaglyph lenses tend to pair red with cyan and magenta with green.
How to reuse 3D viewing glasses
Since the same 3D viewing glasses that were popular in the 1950s are still used in theaters today (the frames might be plastic instead of cardboard), DIYers can follow Burton’s instructions nearly seven decades later, although you might need substitutes for some household products. For instance, a pair of glasses can be turned into a kaleidoscope with the aid of two 1950s-style bouillon cube containers (tea cans might work in modern times). Cut a hole in each container cap and paste one polarized lens over each hole. Then cut a hole in the bottom of one can (you won’t need the second can for anything, only its cap) and cover that hole with clear cellophane (or plastic wrap) so light can shine through from the bottom. Drop bits of hard clear plastic inside. When the caps are stacked on top of each other as eyepieces and rotated, the bits of clear plastic will appear to change colors.
What’s new on the 3D scene
Even though the 3D viewing experience has required the same polarized or anaglyph lenses for more than 70 years, 3D technology has advanced, especially in the last decade. One reason Avatar sparked a surge in 3D movies in the 2010s was that the film crew used new tools to ratchet up the illusion of depth, including motion-capture attire worn by the actors to offer multiple views of the same action, video game–quality computer-generated graphics designed for 3D depth, and stereoscopic cameras that captured scenes with dual images, one for each eye. Of course, on the viewing end, movie-goers still required the decades-old polarized lenses to see the effects, but the results were stunning.
Virtual reality headsets like those from Meta, HTC, and Microsoft also offer 3D viewing. While the VR experience may be immersive and realistic, the cyborg-style headsets are not exactly practical apparel. You’re better off wearing polarized or anaglyph specs in public. Of course, 3D nirvana means no viewing accessory required. Instead, the tech would be in the displays, designed and built to render images stereoscopically. Computer makers Acer and Asus have developed such displays, but so far the effect hasn’t been compelling enough to catch on.
For now, hang on to those 3D movie specs. Burton’s instructions will still work for DIYers interested in optical projects. Perhaps you have your own contemporary ideas.
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Source : Popular Science