Watching your favorite movie in 3d can be an amazing experience: intense colors, objects flying towards you and a sense of literally ‘being in’ the movie. But what makes this possible, are the certain types of 3d glasses that are combined with the 3d technology projected on your screen to produce this magnificent result. It makes sense to ask then ‘what types of 3d glasses are available in the market’?
The answer is in fact simple. There are three types of 3d glasses: anaglyph 3d glasses, polarized ones, and 3d shutter glasses, each one with a different story behind it. Anaglyph 3d glasses were the first to be invented, and we actually owe this invention to Wilhelm Rollmann who managed to materialize his idea in 1852. Rollmann succeeded in creating the 3d effect by taking advantage of the physiology of the human eye and that of the human brain. Anaglyph glasses have two colored lenses; the one is red and the other is cyan (that’s why anaglyph glasses are usually called red-cyan glasses). As a result, one eye sends a to the visual cortex a red covered image, the other eye sends a cyan covered image, which then are inevitably fused by the brain into a single three-dimensional image. In other words, only the red/cyan glasses are enough in this case to produce the 3d effect to the person wearing them. Instead of red-cyan, anaglyph glasses can also be red/green and magneta-green, plus there are a few more color combinations that can cause this ‘popping’ effect to the human eye.
Among the three types of 3d glasses we mentioned, however, polarized glasses are probably the most common. Instead of red/cyan lenses, these glasses have yellow-brownish lenses that act as polarizing filters that restrict in certain ways the amount of light that goes through the lenses. The result of course is the same: the glasses trick your eyes into seeing a three-dimensional image. Polarized glasses were first used to watch 3d movies as early as in 1936 thanks to Edwin Land, and are still used in cinemas, especially in IMAX 3d movies. Nevertheless, although polarized glasses are very effective in creating this 3d effect to the person wearing them, they also tend to make that person look ridiculously funny; therefore, it is better to put them on only after the lights are turned off.
As for shutter glasses, those are very different from the previous two types of 3d glasses. They neither color the image like anaglyph glasses, nor do they filter it like polarized glasses do. Instead what happens is that one lens becomes darker and the other becomes brighter (and vice versa) so fast that you do not even realize it. This contrast and constant shift in brightness/darkness of the image that your retina perceives is what creates the desired 3d effect. Shutter glasses are considered to be the most advanced of the three types of 3d glasses, they are the future in 3d technology, and that is why they are also very expensive.