A 3D movie can be viewed in a number of ways. Early 3D movies used a system called Anaglyph which uses coloured lenses to view superimposed images. It worked, but due to the coloured lenses, the colour of the image is distorted and the effect seems quite primitive compared to more modern techniques. Also, the requirement to wear glasses is a drawback.
Another technique called the Eclipse method, uses a different sort of glasses with LCD shutters. Alternative frames of the movie are from each of the two viewpoints. The LCD shutters are in sync with the frames, so each eye only sees the correct image for that angle. This words well, but syncing with the movie makes it difficult to use in movie theatres. It works well with home viewing, and is often used by gamers to display 3D games.
Most movie theatres use a polarisation technique, which requires special glasses, but doesn’t interfere with colour. Each viewpoint is projected through a polarising filter. Using polarised glasses, it is possible to view each projected view separately. This is probably the optimum method for displaying 3D in a movie theatre, but it still requires glasses.
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