Bradford’s IMAX experience connects visitors to one of the most technically demanding cinema formats ever developed. IMAX originated in Canada, where co-founders Graeme Ferguson, Roman Kroitor, Robert Kerr, and William C. Shaw established what was initially called Multiscreen Corporation, Ltd. in September 1967, later renamed IMAX Corporation. Working through the late 1960s and early 1970s, they set the first projection standards that would define the format for decades.
How the Technology Works
The original and still premium IMAX format, known as IMAX GT, uses an unusual film-transport mechanism called the Rolling Loop, which runs 15/70 film horizontally rather than vertically through the projector. This orientation allows the image width to exceed the width of the film stock itself, producing frames across 15 sprocket perforations rather than the five used in standard 70 mm vertical projection. The result is screens as large as 18 by 24 metres, with a tall 1.43:1 aspect ratio and steep stadium seating that places the audience close to the image. The Rolling Loop technology itself was purchased from Peter Ronald Wright Jones, a machine shop worker from Brisbane, Australia, and adapted by William C. Shaw into the single-projector system the corporation adopted. GT installations often limit their programming to high-quality short documentaries to maintain the integrity of the format.
Later Formats and Digital Systems
The high construction and maintenance costs of GT theatres led to several adaptations over the years. The IMAX SR system arrived in 1998 with slightly smaller screens but still in purpose-built auditoriums at the 1.43:1 ratio, while the IMAX MPX system followed in 2004 specifically to retrofit existing multiplex screens, at some cost to picture quality. Digital formats came next, with IMAX Digital 2K introduced in 2008 and IMAX with Laser 4K arriving in 2014. Both are purely digital and suited to existing theatre retrofits, though neither matches the roughly 70 megapixels of equivalent resolution produced by the original 15/70 film format. Since 2018, the Laser system has also been applied to full dome installations. The standard aspect ratio for most IMAX screens today is 1.90:1, marginally wider than the conventional 1.85:1 theatrical widescreen standard, with the taller 1.43:1 ratio now available only at selected locations.