Everyone loves a good 3-D film experience. You get your cool glasses and have such an immersive experience. Films like Avatar, The Adventures of Tin Tin, Journey to the Center of the Earth and the like have totally changed the perspective of watching films. But have you ever wondered how these 3-D films are made? The concept behind 3-D movies is nearly as old as motion pictures themselves, dating back to the early 1900s. 3-D movie is the short name for a stereoscopic 3-D film, motion picture technology which has its roots based in stereoscopic photography. Based on depth perception, stereoscopic photography creates the 3 dimensional illusion by shooting the image/video at two slightly different angles. The glasses through which such images appear as 3-D are created on the cross-eyed view technique, the same principle as that of binoculars.

Most people see out of two eyes. This is a basic fact that makes possible the illusion of depth that 3-D movies create. The human eyes are spaced about two inches apart, which means that each eye gives the brain a slightly different perspective on the same object. The brain then uses this variance to quickly determine an object’s distance. To test this, simply hold a hand or other object out a few feet. Alternate closing one eye and then the other. The object will appear to move against the background. 3-D movies take advantage of this fact. Two images filmed at slightly different perspectives are projected on a screen. Using a variety of technologies, 3-D movies permit each eye to see only one of them. The brain combines the separate images as if it were looking at an actual object, creating the illusion of depth.
Warning: Geek speak coming up
Stereoscopic photography creates an image known as anaglyph. Although two lenses are used, a single image is created. These are generally superimposed through two color filters, one in red the other in cyan. Thus when a 3-D image is projected using a stereoscopic projector system, glasses with one red and another cyan lens create the cross-eyed effect, to make the image appear as one. This can either be done using two cameras or a camera with dual lenses set a uniform distance and angle from each other. The two angles can also be computer generated graphics.

Since there are two sets of films, special projection hardware is used to display the film. The film appears as a single image with the help of special glasses. Such hardware is not only available for the 70mm movie screen, but can be used for television broadcasting too. There are several new technologies which use alternative techniques cut down on costs. One such technique is ‘RealD 3D cinema‘ technology.

‘RealD 3D cinema’ method uses a light based technique known as the circular polarization for creating the stereoscopic image-type projection of the film. It means that using this projection system, the film need not be shot using two lenses. This reduces the cost considerably as the film can be relayed as both a 3-D projection as well as a 2-D projection, because the film is shot as 2-D but projected as 3-D. Since it’s not a color imbalance but a light based simulation, the glasses for the two are different too.
The next time you watch a 3-D film, you’ll have a better appreciation of what actually went in to the making of that film, be it capturing some insane looking visuals or even computer generated animations! This trend that began in Hollywood is heading to the East and we will soon see 3-D Indian films starting with South Indian Superstar Rajnikanth’s Kochadaiyaan (technically this isn’t the first Indian film in 3-D, My Dear Kuttichathan was the first and was released some 28 years ago but Kochadaiyaan is the first 3-D film using performance capturing technology). We can’t wait!

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