Watching a movie in 3D is quite an unusual experience for some, but over the years people have grown to love that style and now 3D projections are coming back strong. The illusion of an image coming off the screen is nothing more than just projecting two different images at the same time, each meant to be seen by a different eye. How do 3D glasses work and why do you actually need them to see a movie in 3D?
Coloured vs polarized lenses
There are two major ways 3D glasses are made and used in cinemas. The first and probably most commonly known type of 3D glasses are those that have two different colour lenses, usually in the combination of red and green or red and blue. The projector shows two different images in two different colours, each reaching the respective lens and allowing your eyes to see a slightly different picture. It is the brain that does the trick of connecting them together and creating the illusion of a 3D image. However, since the colours have to be superimposed on the image itself, the quality and depth of actual colours of the movie is lost significantly.
Another way of making 3D glasses is by using polarization. This has proven to be much more effective in terms of quality and for now, it is the most frequently used technique. Here, the lenses are the same colour, but they are polarized differently, usually with 45 and 135 degrees relative to the horizon. The movie is projected in such a way that each eye sees only the image the lens is polarized to, thus creating the 3D effect. This technology works with the best 3D projection systems now and it doesn’t seem like there are better options in the future.
The glasses that are used in cinemas can’t be technologically advanced as they would be easily broken or stolen by people. At home, however, the technology in 3D movies came far ahead and now, 3D glasses use shutters on their lenses so that the movie doesn’t have to play two images simultaneously. It all happens at such a rapid pace, our brains don’t really notice, but in fact each image is seen by each eye separately. Doing it that way, the quality is very good and the 3D effect is very realistic, which is obviously a good thing for the viewers and a great competition for wide screens in cinemas.