3D - 2

How do they make 3D movies without red and blue glasses?

My recent trip to Walt Disney World and Universal's Islands of Adventure brought 3D movies to my attention. All of the attractions utilized the same technologies to produce their 3D effects. The thing that really confuses me is that the glasses they give you aren't red and blue, they're kind of like sunglasses (and they're non-electronic), so how do they send each image to the correct eye? One thing I did notice with the goggles is that when I looked at my watch with a specific lens (the left I believe) my LCD watch face was completely black. However, with the other eye I could see my watch just fine. I'd guess they use some kind of light filtering in the the lenses that filter the frames that aren't supposed to be seen with that eye. Another thing I noticed is that when you take the goggles off the screen is really shaky. The closer stuff gets in 3D the further apart the images on the screen get, but I assume that method is used in the older blue and red films too?

Public Comments

1. The glasses they have you wear are polarized. Polarization blocks light waves coming from certain angles, depending on how the polarized material is rotated. Some expensive sunglasses are polarized to block the suns near-parallel light rays, and are commonly used in fishing because you can see fish better when sun glare is reduced. I'm not 100% sure but i think they polarize lenses by cutting microscopic ridges in the glass or plastic. In the case of the 3d movie, the ridges run horizontal in one eye and vertical in the other eye. They then polarize every other frame of the film differently, so you see some with only one eye and the other half with the other, simulating stereoscopic vision. Some cool effects can be achieved with polarized lenses, like if you take two polarized sunglass lenses and rotate them while looking through both of them, the light will fade in and out.
2. The Polaroid version you saw is the best form of 3-D. It's basically the same process that got started back in the 1950's with "Bwana Devil" and "House of Wax". It uses two seperate rolls of film (left and right images) in projection as well as photography. It can be done with two synchronized projectors (the old way) or with both images on the same film. The red/green 3-D process is called anaglyphic and it goes way back to the 1930's. It was used for 3-D comic books and is used on 3-D videos and for 3-D TV. It is not nearly as effective as the Polaroid variety. It is easy to do in movies because it just needs one projector to show. By the way, with Polaroid projection, you also need a silver screen...normal white screens don't work.
3. The June 2006 issue of Popular Science magazine has an entire article about 3D movies!