IMAX is a film projection system which has the capacity to display images of far greater size than conventional film. A standard IMAX screen in 22m wide and 16m high, but can be larger.

The desire to increase the visual impact of film has a long history. Film formats such as Cinemascope and Vistavision developed the image and in the late 1960s there were attempts at multi-projector systems. While impressive, the system was cumbersome, difficult to set up and the joins between the screens were difficult to hide.

The IMAX (IMage MaXimum) was developed by three Canadians - Graeme Ferguson, Roman Kroitor and Robert Kerr. It uses a special 70mm/15 film stock (sometimes called "15/70" film, to distinguish it from conventional films that are also shown at some IMAX theatres), which is three times the size of conventional 70mm stock, has three times as many perforations, is a different ratio, stronger and does not carry a sound track.

Drawing the film through the projector was a difficult technical problem to solve, using a conventional system simply tore the film apart and was unable to hold the film flat to the lens. IMAX required a number of innovations - the film runs horizontally with a ripple technique called rolling loop, the film moves in a wave with each frame being held flat onto the projection elements by a field flattener vacuum. The shutter is also open for around 20% longer than in conventional equipment and the light source is brighter and requires water-cooling. An IMAX projector is therefore a substantial lump, weighing up to 1.8 tonnes. Further improvements to the technique include a dome projection option (OMNIMAX) and the possibility of a faster 48 fps rate. While IMAX does not include a sound-track it has specified a separate six-channel sound system. A 3D projection format is used for some films in over 100 theaters.

There are around 230 IMAX theatres in 34 countries around the world. Half of them are in commercial theater complexes; the other half in educational locations.

The first IMAX film was demonstrated at EXPO '70 in Japan. The first permanent IMAX system was set up in Toronto in 1971. Although IMAX is an impressive format from a technical perspective, its popularity as a motion picture format has traditionally been limited. The majority of films in this format tend to be documentaries idealy suited for institutional venues such as museums and science centers.

Recently there has been some interest in broadening the use of the IMAX format, this is particularily apparent from the recent Disney film, Fantasia 2000.

The recent advance in IMAX digital remastering has led to the release of 35mm films in an IMAX format. A high-publicity movie released for IMAX in 2003 was The Matrix Reloaded.

James Cameron filmed a movie on the Titanic in 3D IMAX format, Ghosts of the Abyss.

Up to 2002, eight IMAX format films have received Academy Awards nomination with one win, the animated short, The Old Man and The Sea in 2000.

• Fantasia 2000
• Cirque Du Soleil -The Journey of Man
• To Fly! - top-grossing IMAX with a box office of $82,500,000
• Everest
• Antarctica
• Grand Canyon: The Hidden Secrets
• T-Rex: Back to the Cretaceous
• Space Station
• Mysteries of Egypt
• Cyberworld 3D
• Haunted Castle
• Star Wars Episode II: Attack of the Clones
• The Lion King
• Beauty and the Beast
• The Matrix Reloaded

• IMAX - official site
• IMAX box office numbers