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Tech Behind Modern 3D Movies

As I sat through Avatar 3D, I kept wondering how they made it all work. With the old red/blue glasses (anaglyph), it was pretty easy to understand. One eye filtered out one color and the other eye filtered out the other color and you ended up sending separate images to each eye. But how does the new 3D work? Time to surf the interwebz…

There are a few different types of 3D in use, but the most common is RealD. When you look at the screen without glasses, you see images that are blurred (two unaligned images) and the amount of the blur correlates to the virtual depth. These two images are projected with opposite circular polarized light. One lens get the left handed polarization while the other lets the right handed polarization through. The end result is the same as the red/blue glasses: each eye sees a unique image.

Imax 3D uses linear polarized light. The downside to this is that as the viewer tilts their head, the image can become distorted. You tend to see images pop out of the screen instead of viewing virtual depth into the screen. It creates a lot of eye strain and can give you headaches after watching for more than a half hour.

The other 3D technology is Dolby 3D. It’s the hardest to find of the three, and you can read more about it in this article which discusses all three. The short story is that the end result is similar to RealD: low eyestrain, good viewing experience.

One problem I see with all of these solutions, is you end up watching through tinted glasses. It reduces the amount of light that makes it into your eyes. They have to blow out the brightness on the film which can lose some of the fine detail in brightly lit areas. However, in contrast to 3D at home, I think 3D in the theater will take off as a differentiating factor to draw people back to the theaters.

Want to find a theater which uses a specific 3D technology? This site is a good collection of places to search for that info. In addition to all the links scattered through this post, Wikipedia has a good overview of 3D technology.