The separation of the two pictures or sequences of pictures (film) for the right and the left eye by glasses can be realised with several methods.

At the one side by colour filters, which are combined in this way, that the colours seen by the left eye can’t be seen by the right eye: red-green [a], red-blue [b] glasses. Therefore the two images (films) must be copied in this colour in another ( Effect: only black and white picture (film)).

Glasses for colour-TV [c]. Hereby with simple methods of filming they get a 3D effect. The normal film camera is moving with a constant rate from right to left. The glasses have an dark filter in front of the right eye. This delays the perception of the right side. Caused by the move of the camera, the two eyes perceipt two different views, which are together a 3D view of the scene.
The restricition for film design (permanent constantly moving of the camera) are so strong, that this is only acceptable for documentary films (Effect: color film with 3D effect).