IMAX is a proprietary system of high-resolution cameras, film formats, film projectors, and theaters known for having very large screens with a tall aspect ratio (approximately 1.43:1 & 1.90:1) and steep stadium seating.
Graeme Ferguson, Roman Kroitor, Robert Kerr, and William C. Shaw were the co-founders of what would be named the IMAX Corporation (founded in September 1967 as Multiscreen Corporation, Limited), and they developed the first IMAX cinema projection standards in the late 1960s and early 1970s in Canada. Unlike conventional film projectors, the film runs horizontally so that the image width can be greater than the width of the film stock.
When IMAX was introduced, it was a radical change in the movie-going experience. Viewers were treated to the scene of a gently-curved giant screen more than seven stories tall (75 feet (23 m), with the tallest measuring 117 feet (36 m)) and steep stadium seating that made for a visually immersive experience. This was enhanced by a sound system that was far superior to the audio at typical theaters in the years prior to the advent of THX. Some IMAX theaters have a hemispheric dome screen geometry, which can give the viewer an even more immersive feel. Over the decades since its introduction, IMAX evolved to include "3D" stereoscopic films, introduced in January 1998, and then began to proliferate with a transition away from analog film into the digital era. Beginning in May 1991, a visceral dimension of the movie experience was added by having the audience's seats mounted on a full-motion platform as an amusement park ride in IMAX ride film theaters.
With the advent of digital projection, the IMAX brand has also been applied to lower-resolution imaging systems, causing some degree of confusion among the viewing public.