How 3D Glasses Work – From Blue and Red to Polarized and Beyond

In the past couple of years, we’ve seen an incredible push towards 3-D technology in movies. Of course, the concept has been around for decades, but it had been largely abandoned until recent hits, such as Avatar and Up, showed everyone just how innovative the technology could be. This article examines the history of 3-D glasses, and how they work to create those lifelike images that keep you coming back to the theater.

How do 3D glasses work?

The entire concept of inducing 3-D vision is based around your capacity for binocular vision. Basically, your two eyes work together to gauge the distance between you and the object that they’re focusing on. This works due to the placement of the eye, and how far each object is perceived according to each eye, creating a triangulation effect that allows things that are within 20 feet of you to have a very tangible three-dimensional look. Each eye looks at the object at a slightly different angle, and your brain uses these two distinct images to figure out your distance from it. You can still perceive distance to an extent when you only see with one eye, but you definitely don’t get the accuracy that you have with both eyes and the binocular vision that comes with it.

How do red and blue 3D glasses work?

Due to the distinct signal you get from a television screen, a unique form of 3D has to be utilized, where there are two images placed on the screen, one in blue or green, and the other in red. You then use certain glasses that have a red filter on one eye, and a blue filter on the other. Viewing the image through both these filters will remove one of the colors from each eye, only leaving the other. Thanks to the aforementioned binocular vision, the brain will fill in the perceived gaps in the image, leaving you with an image that appears to pop out from the screen. Keep in mind, however, that since there’s such a limited color spectrum to this particular method of 3D, it’s hard to have very distinct colors in your 3D movie. This was the favored method of 3D moviemaking when it had its heyday in the 1950s and 1960s, but has since fallen out of favor now that more innovative and quality technologies have been developed.

How do polarized 3D glasses work?

Polarized 3D glasses are the wave of the future, and have been used at theme parks for many years before being put into widespread use in current and recent features. Polarization occurs when a lens is oriented or created in a way that will only let certain types of light through, via microscopic slits in the lens. This form of 3D uses two different projectors to transmit the film onto a screen – both of those projectors possess a different polarization. You are then given a pair of polarized 3D glasses that are meant to interpret the images the projector provides you. When these two are played at the same time, your polarized 3D glasses only let in the particular image with the polarization that matches the lens. Thanks to this innovative technology, you can have a more vivid color image, dramatically improving the picture quality of most motion pictures.

Now that you know how 3D glasses work, you can understand a little bit more about how those true-to-life images you see on your movie theater screen work, and appreciate the artistry that goes into creating these works of art.