3D movies have been around for a very long time now and although it seems like it was only the recent years that made it widely popular, in the United States the biggest rise of 3D movies was around in the 1990s. There are two main types of 3D glasses that are used in the cinemas and one more popular for at-home purposes. How do 3D glasses work?
The illusion of seeing a 3D image on the screen, often referred to as stereoscopy is nothing more than just tricking your brain into seeing two pictures and overlaying them on top of one another. How does it actually work?
With the traditional, cheap cinema 3D glasses, you have two options – different coloured lenses or opposite polarization. With the first one, movies were edited in the post-production stage so that one eye could see a slightly different mage than the other and it was done by using two slightly different RGB schemes. While one eye was seeing red, the other one saw blue and the brain was connecting the images together as it had to process them simultaneously. This technique was proving to be good and is still used in many cinemas around the world, although where quality counts, there are better options available.
Lens polarization is another way of making 3D glasses. Here, the movie is projected in such a way that the image designed for the left eye is polarized differently to the one for the right eye. Typically, producers use polarization of 45 and 135 degrees relative to the horizon and project the two images simultaneously, with one eye able to see only one of them.
The home revolution
3D movies and TV sets have entered the market in the recent years, making not only great competition for cinemas, but for their 3D glasses as well. If you really wanted good quality image and glasses that are far more advanced, most TV sets will work with specially designed shutter glasses. Here, the picture for each eye is not shown simultaneously – the lenses are rapidly closing and opening, allowing each eye to see its image before closing it off for the other one. This couldn’t work at the cinemas mostly because of the price of such 3D glasses. If you still want to go and see a good quality movie, look for polarized glasses.