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     Dr.(Phys.)Dipl.-Ing.Ralf-Udo Hartmann

Rolling Loop

The Canadian IMAX system of cinematography is considered to be the largest motion picture in the world, and its very name is a synonym of Maximum Image relating to the 48.5mm x 69.5mm frame size when 70mm film is projected horizontally. For almost 100 years, engineers in the motion picture industry have come up with nothing better than either a simple claw movement or an intermittent sprocket to transport film through a projector. This works well for film sizes up to and including conventional 70mm, but problems occur with acceleration loads on wider films which can cause unsteadiness and a very short print life.

Over in Brisbane, Australia, there was an engineer called Ron Jones who had always been fascinated by cinematograph equipment. He owned a repair workshop and back in the 1960's he had been working on an entirely new film transport system. He found that he could advance film through a projector in gentle caterpillar-like waves on to fixed registration pins using compressed air jets to cushion the film movement. Ron called his unique system 'The Rolling Loop' and immediately took out a patent.At about the same time producer/

cameraman Graham Ferguson and his partner Roman Kroiter were making multi-screen films for the Canadian Government, often using several 35mm cameras strapped together. Their dream was to find a large format system which would produce a single image on a giant screen, with audiences sitting relatively close so that the projected image covered the entire field of vision of the viewer. This concept was quite different from normal viewing practice and meant that the back row of the audience would have to be sitting at a distance closer than the width of the screen. The problem always returned to the system of projection, and both Graham and Roman visited the New York World Fair to see a 70mm film with a 10 perforation pull-down. Even this was not big enough for their purpose, and when they eventually heard about the Rolling Loop patent they realized that this might just be the answer. Graham was on the next plane to Brisbane.

Ron Jones was rather taken aback by the sudden interest in his system, and whilst Graham thought that all Hollywood would be there clamoring for the patent rights, he was, in fact, the only one. So without any competition, he bought the world rights and returned to Canada with the prototype for a revolutionary new film transport system.

Hand-made model of the rolling-loop mechanism from IMAX movie projectors!

                  IMAX Projector Assembly an new generation MPX IMAX Projector
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