3D Technology

Stereoscope: The main concept behind 3D technology relies on the fact that our eyes  are a certain width apart and because of this difference, we are able to see two images at the same time, which are identical with some alterations.Our brain is able to discover these differences and synch both of them together using geometry and maths, creating the 3D effect.

 The anaglyph glasses makes use of this concept by giving a different colour for each eye(blue and red), thus making them have a different perspective of the film. In a film theatre, two different coloured images are projected onto the screen and the different coloured lenses filter the images allowing a different image to enter each eye. However a problem with using this kind of glasses was that the quality of the images were very poor since it didn't allow a variety of colours since colour was already being used for separation. It also gave the images a ´ghost´ effect by combining them together.
An additional problem with the technology was that when 3D was first launched many people complained about feeling dizzy or straining their eyes to watch the films.

 Polarized glasses are now more commonly used, this technique takes advantage of the fact that light can be polarized. It does this by projecting two different images on the screen which have different orientations, one is vertical and the other horizontal. This corresponds to the lenses on the glasses which also share different orientations, this allows a different image to be seen by a different eye because the eye which has a lens with a vertical orientation will see only the image with the horizontal orientation and vice versa. However this technique also has problems, the colour and 3D effect of the film can be ruined if the person watching moves their head, this is because it distorts how the waves enter the eyes. On the other hand a solution to this problem has been found through the use of projectors who have a clockwise and a anticlockwise spin, this images correspond to the different lenses on the glasses which separate the images, this is called rotational polarity.

This video shows that not everyone enjoys 3D movies despite the majority of new films being released are now in 3D.

Source 1 Source 2