How IMAX Works
CREDIT: (NASA/Paul E. Alers)
A classic IMAX theater gets its immersive qualities from two separate sources: the IMAX film itself, and the design of the theater.
Basically, an IMAX film frame has more than eight times the area of a standard movie film frame. Standard Hollywood movies are shot on 35mm film that runs vertically through the camera. The picture occupies a rectangle that's about 22mm wide by 18.6mm high, or about 409 square millimeters.
IMAX movies are shot on 70mm film that moves horizontally through the camera. The picture occupies a rectangle that's 70mm wide by 48.5mm high, covering 3,395 square millimeters.
Obviously, the resolution can be much nicer, but it comes at a cost. IMAX cameras use three times more film than standard movie cameras. The cameras themselves have to be large, and the projectors even larger. Since the film resolution will magnify film jitter, each frame has to be held precisely in place during exposure and projection.
Then there's the theater, which usually involves a large screen, and a steeply sloped bank of seats that are closer to the screen than in a standard theater . Speakers are placed around the periphery for an immersive audio experience. Some are even placed behind the screen, which has tiny perforations to let the sound through.
There's no standard screen size, but classic IMAX theater screens can be 100 feet or more wide and nearly as tall. The screens at your neighborhood multiplex theater might be 60 feet wide and 30 feet high. However, there are IMAX installations in conventional theaters as well.
IMAX started when a group of Canadian film-makers began experimenting with the wide-screen films that were a hit at the EXPO '67 world's fair in Montreal. Those films required a clumsy multi-projector set-up, and the IMAX team set out to make a single-projector wide-screen system.
The first IMAX films were shown at the EXPO '70 fair in Japan, and the first permanent IMAX theater opened in 1971 in Toronto.
IMAX was adapted for 3-D as early as 1986. IMAX began offering a system to re-master 35mm Holly films in IMAX format in 2002. The first Hollywood movie to be simultaneously released in conventional and IMAX formats was "Matrix Revolutions" in 2003. "Polar Express" in 2004 was the first full-length Hollywood movie to be released in IMAX 3D format. IMAX released a digital system in 2008.
At last count there were 430 IMAX theaters, spread across 48 countries. The total includes 309 commercial theaters, and 121 institutional theaters, typically museums.