Sep 18, 2009
by Philip Jaeger, Director of Operations
Many of you have probably turned your head to stare at the back wall of the IMAX and looked up at the windows impatiently waiting for your movie to start. So in this blog, I thought it might be a good idea to tell you what happens on the other side of those windows.
Starting off, the IMAX Theater at the Evergreen Aviation & Space Museum is one of the best in the world in terms of sound, quality of image and multi-use capability. The sound comes from six speaker systems arranged throughout the theater. Each individual speaker cone is laser aligned into the theater for an optimum large sweet spot of sound. It took one week to set the sound levels so that all the speakers sound exactly the same on every frequency the human ear can detect. The IMAX SR projection system is a film-based system.
You have probably noticed the large movie screen (the largest one in Oregon) in front of you, but did you realize it was painted silver and covered with holes? The holes allow all the sound energy to bounce freely throughout the theater and not move the screen like a giant bed sheet in the wind. The silver paint is part of the 3D process.
Inside the projection booth, there are two giant projectors, one for the left eye of film and one for the right eye of film. If we are running a normal 2D movie, we can use either projector by itself. But to make a 3D movie, we need a film for each eye. The films are run through the projectors at the same time, and then the image is projected through a polarized piece of glass. To keep the image polarized (especially the colored light that is actually the image), the screen is painted silver to reflect the light like a giant mirror. Then with your 3D glasses on, your left eye only sees the left image and your right eye only sees the right image, and then your brain fuses the two together.
You might notice in the pictures some really large black metal circles. These are the platters that hold the film while it is playing. For a normal 45 minute IMAX movie, there are two and half miles of film per eye. The total weight is more than 200 lbs. For a two and a half hour movie, that jumps up to a six foot diameter platter that holds eight miles of film, which weighs over 700 lbs. One other fun fact about the film is that each individual IMAX frame holds 50 MB of data, if digitized, and is the equivalent size to 10 regular motion picture frames.
I hope you enjoyed your tour behind the scenes, and make sure to stop by and see our new IMAX 3D movie Wild Ocean.