IMAX

IMAX (abbreviation of Maximum English Image ) is a process Cinéma tographic allowing the projection of images of dimensions and resolutions higher than the traditional cinema (a screen IMAX measurement at least 22 m of length and 16 m in height). Consequently, the architecture of rooms IMAX is different: the resolution of the image being more important, the seats are placed more close to the screen and are directed of 23° in the domes OMNIMAX.

A little history

The will to increase the visual impact of a film exists since the creation of the Cinéma: the best examples are the fakings of Georges Méliès or the arrival of the train in station of Ciotat, by the Frères Light (the train was filmed of face and of the spectators left the room while howling, of fear of finishing crushed).

There was initially the relief with wearing of glasses with 2 colors, an red eye and a blue eye, a film of Arnold Jack is turned with this process the Strange Creature of the black lake , proceeded used for the black and white. This process of separation of the colors is nevertheless very tiring for the eyes.

Later developed polarizing glasses with facets, process used still today in particular for their attraction of cinema in relief, in some rooms of the Futuroscope or in the parks Disney, to which was recently added a floating floor in the room in order to make “ sentir ” with the spectators emotions of film, movements of camera, tremors, etc

Abel Gance, as of 1927, carries out certain parts of its famous Napoleon on triple screen.

Alfred Hitchcock has recourse to the process of relief for its film the crime was almost perfect , color film which imposes to the spectators the wearing of polarizing glasses, which increases the cost of exploitation and embarrassment the visual comfort of the spectators.

the house of the the United States at the time of the International exhibition of Brussels in 1958 had revealed the Circlorama : a vision with 360° by means of 11 screens laid out around a circular room. The problem was all the same for the spectators of knowing in which direction to look at, and for the realizer to manage to envisage their reactions. Moreover, the proximity of the projectors in the center of the room could present a fire hazard.

the processes Cinemascope (objective Hypergonar invented by Christian Henri) and Vistavision widened the image starting from a reel 35 mm. There existed also the Cinérama, technique requiring several projectors. Although impressive, the Cinérama was difficult to implement, the junction between the screens being too visible.

System IMAX was developed by three Canadians: Graeme Ferguson, Romance Kroitor and Robert Kerr. During the World Fair of 1967 which was held with Montreal, with the Quebec, their system multi-projector encountered difficulties, which pushed them to create a system mono-projector. During the even exposure of 1967, the French house precisely exposed a system monoprojector on concave half-sphere: the Panrama.

The first demonstration of process IMAX took place with Ōsaka, with the Japan, in 1970. The film of demonstration projected had been made with three cameras simultaneously, which was to allow “ to create an impression evoking the relief ” (allegation already held in their time by the Cinemascope, then by the Cinerama, and resting on no serious basis).

First cinema IMAX was inaugurated in 1971 with Toronto.

In May 2003, there existed 230 cinemas IMAX in 34 countries, half of them being rooms with nonlucrative goal (scientific museums and centers). Realizers as Jean-Jacques Annaud gave an artistic credibility to the process. Some rooms IMAX also closed in the world, or passed under user license as that of Defense close to Paris which reopened on April 27th, 2006.

Technique used

The goal of the IMAX being to widen the image, the Pellicule proceeds horizontally, on both sides camera and not vertically, upwards, as on a traditional camera.

On a film 70 mm traditional, the part of the film devoted to the image are 48,5 mm wide for 22,1 mm in height. For the IMAX, the image is 69,6 mm wide for 48,5 mm in height.

For a film of the same duration, a film IMAX will be three times longer than a traditional film: approximately 1 Kilometer of film for 10 minutes of film.

Cameras IMAX use films Estar (registered trademark of Kodak, equivalent with the Mylar of Dupont), much more resistant than a conventional film. Indeed, the chemicals used for the development of the films deteriorate them. This resistance is useful for the projectors IMAX which are very sensitive to the variations thickness of film or the deterioration of the perforations located on each side of the film (or rather in top and bottom in the case of a film IMAX).

Format IMAX is also called “ 15/70 ”, in reference to the 15 perforations per image of 70 Misters.

Contrary to a traditional film, a film IMAX does not comprise a track its, in order to devote a maximum of film to the image: a tape recorder with bands 6 pistes/35mm is thus synchronized with film (this system was already used in the traditional cinema for doublings and the insertion of sound effects). Since the years 1990, the tape recorder with bands was replaced by its numerical equivalent, synchronized by code SMPTE (of a highher degree of accuracy), which with open the way to SDR and the Dolby DIGITAL.

The IMAX was a true technical challenge. Indeed, no projector 70 mm of the time had the precision necessary to “ the IMAX experiment; ”. William Shaw, of IMAX, adapted a cylindrical lens to the projector, added an air compressor in order to flux the development of film and to flatten the film in well the corridor of projection. The perfect alignment of the image is ensured by four barbs which come to plug in the perforations with the four corners of the image. Arms are used to slow down the film, in order to avoid the microphone-tremors during insertions of the barbs in the perforations. the obturator remains open approximately 20 % longer than in the case of traditional equipment and the bulb is more powerful. The largest projectors, equipped with lamps from 12 to 18 kw with cooling system with water, can weigh up to 1,8 tons.

Among the evolutions of standard IMAX, one can note the domes OMNIMAX (as with the Futuroscope of Poitiers or Géode of the Cité of Sciences and Industry, with Paris), the films in 3 dimensions, the dynamic cinema, the possibility of filming with 48 images a second (usually, a film with the cinema is diffused with 24 images a second and with 25 images a second on television). The audio system was also improved to allow its 3D.

And the spectator?

All these combined techniques (the immense screen, its proximity, sounds spouting out of all shares) make live with the spectator a true visual experiment. He is literally coated by the image and the sound. The dynamic cinema (the seats move in a way synchronized with the movement of the camera) reinforces obviously this impression, certain spectators suffering even “ Sea sickness ” during projection.

External bonds

Official site
IMAX with the boxoffice

Simple: IMAX

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