How do 3D films work?


Many people wonder how filmmakers can make an image seem like it jumps off the screen so far you feel like you can touch the objects and characters. But the process is quite simple.

First of all, you have to understand how the human eye works. As we have two eyes that sit side by side, we perceive everything we see from two different angles. Although those angles might be only slightly different, they are different enough to give us depth perception. We can judge the distance of things based on how severe the difference in angle is in terms of the object that we are looking at.

3D films work with these dynamics. Two camera lenses sit side by side and film the content of the film from slightly different angles. From there, the two images are superimposed onto the screen using different types of light for each “eye”. The technology has changed over the years, so the type of light being used for each side is dependent on the system in use. They all, however, work under the same principle, which is to show two images stacked on top of one another yet not aligned exactly so as to imitate the way our eyes see things.

Retro image of a 1940’s film noir mature gangster / private detective wearing a suit and fedora hat, pulling out a pistol / gun from his jacket. He stands on a dock by a vintage car with a generic city in the background, under a dark and stormy evening sky. Sign is fictional.

When the moviegoer sits down in the theatre with their blue and red glasses, the same goal is achieved, no matter what kind of 3D technology is being used. One of the lenses will only let the type of light through that is intended for the eye behind it, and the other will block out the light waves that the other eye is seeing while allowing through the light intended for its side. By controlling which type of light makes it to which eye, and placing the images on the screen at slightly different angles, the human brain is tricked into thinking that it is seeing something tangible.


Next time you go to a movie house to see a 3D movie, pay attention to the colours on screen and the overlay to see for yourself how the technology works. Who knows? Maybe you will discover something about how you perceive things with your own eyes.

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