CRITERIA B

IMAX theatres’ astonishing quality is achieved by using film shots that are about 10 times larger than the regular 35 mm film stocks. These are square when shot and hence are not in the same proportion of the sides of the screen - they need to be compressed. The 75 mm ones give about double the resolution and are in the proportion of the screen sides. IMAX film shots are 70 mm high and 15 perforations wide (perforations are holes in the film stock that keep it steady)(howstuffworks.com, 29/01/09). Their projectors are different to the regular ones in several ways:
• The film in their projectors moves through horizontally rather than vertically.
• The shutter in these projectors opens for a longer time (rather than for a second) so more light in shone through.
• Bulbs in general theatre projectors are about 150- 200Watts while the IMAX lamps are 15, 000 Watts.
• The IMAX projectors weight approximately 2 tonnes
These projectors project the movie to a large dome which is approximately 30 metres wide – large enough to fill one’s field of vision.














Layout of an IMAX dome
http://entertainment.howstuffworks.com/imax1.htm

IMAX also uses a six channel surround system for its sound technology. This, in a typical home theatre system consists of 6 speakers – three front speakers (right, left and centre), a left and right surround speaker and a rear speaker – and a subwoofer (it is usually referred to as a 6.1 surround system due to the addition of the subwoofer) (howstuffworks.com, 31/01/09).
Also, IMAX uses 3D technology to enhance their films. LCD (Liquid Crystal Display) shutter technology, combined with polarized lenses (here, two synchronised projectors, with two different polarisations air the movie on the screen) makes IMAX movies very different to the others (howstuffworks.com, 31/01/09).