A Look at the Technology Behind How 3D Movies Work

Cheesy blue and green three-dimensional glasses might have been fun, but they’re hardly representative of how modern 3D movies work. Most cinema locations have standardized around polarized glasses, which work much the same way that high-end sunglasses do. Projectors reproduce two different sides of an image and transmit them as beams of light toward a screen that are polarized in opposite ways from one another.

Moviegoers don special glasses that permit only one portion of the light spectrum to enter each of their eyes. When a person’s brain is confronted with two disparate streams of light in this way, it starts to interpret it as a single stereo image. This gives the illusion that someone is watching actual events unfold in front of them as opposed to a single flat picture on a screen. Creative applications of this technology have actually made it possible to remaster existing films in 3D.

Turning Flat Images Into Living Ones

Stereoscopic movies work because of what’s known as binocular vision. People view the world around them in three dimensions because the difference between what they see in each eye gives it depth. Separating up the images on screen until there is enough spacing between them to simulate actual depth is usually enough to present an otherwise 2D movie as a 3D one as long as everyone in the audience is wearing a set of compatible 3D glasses.

Hollywood film restoration crews have long used a similar process to turn films with a mono soundtrack into one with stereo sound. They simply divide information from the existing sound design into a pair of separate channels and balance the loudness between them. By listening to each channel with a single ear, moviegoers feel like the action is happening around them. While adapting this process for visual imagery isn’t trivial, the conversion process hasn’t been as difficult as many in the industry might have imagined. In fact, electronic 3D glasses have made it possible for bring stereoscopic movies into home theaters.

Advanced Electronic Switching Glasses

Rather than relying on different polarization measurements, designers of electronic glasses instead create the illusion of a world with depth by alternating the path to each of the two visual channels. Some of the earliest 3D televisions relied on active glasses with shutters in them that closed both the left and right lenses at a rate of 60 times a second each.

While this technology is considerably more expensive than competing ones, some cinematic aficionados claim that it provides a much better experience than polarized glasses can offer. Since it allows viewers to freely look at the screen in front of them, they see everything in the same color spectrum they would if they weren’t using 3D glasses. Unfortunately, the shutter system can make movies flicker and might even make the screen look dimmer than polarized glasses would.

Regardless of any of these technical limitations, it’s clear that moviegoers themselves will continue to enjoy whatever films get released utilizing 3D technology and features.