film formats

IMAX is a motion picture film format and a set of proprietary cinema projection standards created by a Canadian company of the same name. IMAX increases the resolution of the image by using a much larger film frame. To achieve this, 65 mm film stock passes horizontally through the cameras. Traditional cameras pass film vertically. In order to match standard film speed of 24 frames per second, three times the length of film moves through the camera.

There are 583 IMAX theaters in 48 countries (China is the second largest market after the US with roughly 25 theaters). The desire to increase the visual impact of film has a long history. In 1929, Fox introduced Fox Grandeur, the first 70 mm film format, but it ultimately lost out to 35mm film, which remains the industry standard. In the 1950s CinemaScope and VistaVision widened the image from 35 mm film, following multi-projector systems such as Cinerama. While impressive, Cinerama was difficult to install, and the seams between adjacent projected images were difficult to hide.

The IMAX system was first proposed by Canadian filmmakers Graeme Ferguson and Roman Kroitor. During the ‘Expo 67’ World’s Fair in Montreal, Kroitor’s ‘In the Labyrinth’ and Ferguson’s ‘Man and the Polar Regions’ both used multi-projector, multi-screen systems. Each encountered technical difficulties that led them to found a company, initially called ‘Multiscreen,’ with a primary goal of designing and developing a simpler approach. The single-projector/single-camera system they eventually settled upon was designed and built by engineer William C. Shaw, based upon a novel ‘Rolling Loop’ film-transport technology purchased from Australian inventor Ronald Jones. Later, when it became clear that a single, large-screen image had more impact than multiple smaller ones, Multiscreen changed its name to IMAX.

‘Tiger Child,’ the first IMAX film, was demonstrated at ‘Expo ’70’ in Osaka, Japan. The first permanent IMAX was in the Cinesphere in Toronto in 1971, and is still in operation. During ‘Expo ’74’ in Spokane, Washington, a very large IMAX screen that measured 90 × 65 m (300 × 213 ft) was featured in the US Pavilion (the largest structure in the expo). About 5 million visitors viewed the screen, which covered the viewer’s total vision field when looking directly forward. This created a sensation of motion in most viewers, and motion sickness in some. An IMAX 3D theater also is in operation near the former ‘Expo 67’ in Montreal. The first permanent IMAX Dome installation, the Eugene Heikoff and Marilyn Jacobs Heikoff Dome Theater at the Reuben H. Fleet Science Center, opened in San Diego in 1973. It doubles as a planetarium. The first permanent IMAX 3D theater was built in Vancouver for ‘Transitions’ (the first 3D IMAX film) at ‘Expo ’86,’ and was in use until 2009.

The IMAX format in the US has traditionally been employed for specialty applications. The expense and logistics of producing and presenting IMAX films has led to approximately 40 minute shorter running times than conventional films. The majority tend to be documentaries that are suited for institutional venues such as museums and science centers. IMAX cameras have orbited the earth, climbed Mount Everest, explored the bottom of the Atlantic Ocean, and visited the Antarctic. An IMAX documentary about the success of the Mars Exploration Rovers was released in 2006, titled ‘Roving Mars’ and used exclusive data from the Rovers. One of the first attempts at presenting entertainment in the IMAX format was ‘The Rolling Stones: Live at the Max’ (1991), an 85-minute compilation of concert footage filmed in IMAX during the band’s 1990 ‘Steel Wheels’ tour, edited to give the impression of a single concert.

In the 1990s more entertainment short films were created, notably ‘T-Rex: Back to the Cretaceous’ in 1998 and ‘Haunted Castle’ in 2001 (both in 3D). In 1995, French director Jean-Jacques Annaud directed ‘Wings of Courage,’ the first dramatic picture shot for IMAX. In 1998 and 1999, ‘More’ and ‘The Old Man and the Sea’ became the first short films produced using the IMAX format and both earned Academy Award nominations, with the latter winning (currently the only IMAX film to win an Oscar). In 2000, Disney produced ‘Fantasia 2000,’ the first full-length animated feature initially released exclusively in the IMAX format.

In order to use more of the image area, IMAX film does not include an embedded soundtrack. Instead, the IMAX system specifies a separate six-channel 35mm magnetic film synchronized to the film. This is the same technology as was used to provide the 7-channel soundtrack for Cinerama. By the early 1990s, a separate digital 6-track source was used. The audio plays off a hard disk drive as a single uncompressed audio file containing the 6 channels, which are converted directly to analog rather than using a decoding method such as Dolby Digital. IMAX theaters place speakers both directly behind the screen and around the theater to create a three-dimensional effect.

Drawing the large film through the projector presented challenges for both the camera and the projector. Conventional 70 mm systems were not steady enough for the 586× magnification. On the projector side, William Shaw adapted an Australian patent for film transport called the ‘rolling loop’ by adding a compressed air ‘puffer’ to accelerate the film, and put a cylindrical lens in the projector’s ‘aperture block.’ The projector uses a vacuum to pull the film into contact with this lens. Thus the ‘field flattener’ flattens the image field. The lens is twice the height of the film and connects to a pneumatic piston so it can be moved up or down while the projector is running. This way, if a piece of dust comes off the film and sticks to the lens, the projectionist can switch to the clean side of the lens at the push of a button. The lens also has ‘wiper bars’ made of a felt or brush-like material which can wipe dust off the lens as it moves up or down.

The projector’s shutter is open around 20% longer than in conventional equipment and the light source is brighter. The xenon short-arc lamps are made of a thin layer of fused quartz and contain xenon gas at high pressure (367 PSI); because of this, projectionists are required to wear protective body armor when changing or handling bulbs (a cracked bulb would explode into quartz shrapnel).  An IMAX projector weighs up to two tons and is over 178 cm (70 in) tall and 195 cm (77 in) long.

IMAX Corporation has released four projector types that use its 15-perforation, 70 mm film format: GT (Grand Theatre), GT 3D (dual rotor), SR (Small Rotor), and MPX, which was designed for retrofitted theaters. In 2008, the company introduced a digital projection system, which it has not given a distinct name or brand, designed for multiplex theatres with screens no wider than 21.3 m (70 ft). All IMAX projectors, except the standard GT system, can project 3D images. A standard IMAX screen is 22 × 16.1 m (72 × 52.8 ft), but can be larger. IMAX theatre construction differs significantly from conventional theatres. The increased resolution allows the audience to be much closer to the screen; typically all rows are within one screen height; conventional theater seating runs 8 to 12 screen heights. Also, the rows of seats are set at a steep angle (up to 30° in some domed theaters) so that the audience is facing the screen directly. IMAX theatres are described as either ‘Classic Design’ (purpose-built structures), or ‘Multiplex Design’ (retrofitted auditoriums).

In the late 1960s the San Diego Hall of Science (now known as the Reuben H. Fleet Science Center) began searching North America for a large-format film system to project on the dome of their planned 76 ft (23 m) tilted dome planetarium. The standard IMAX projector was unsuitable for use inside a dome because it had a 12 ft (3.7 m) tall lamp house on top. IMAX Corporation redesigned its system, adding an elevator to lift the projector to the center of the dome from the projection booth below. Spectra Physics designed a suitable lamphouse that took smaller, 18 in (46 cm) lamps and placed the bulb behind the lens instead of above the projector. In 1970, Ernst Leitz Canada, Ltd. (now ELCAN Optical Technologies) won a contract to develop and manufacture a fisheye lens projection system optimized to project an image onto a dome instead of a flat screen.

The dome system, which the San Diego Hall of Science called OMNIMAX, uses films shot with a camera equipped with a fisheye lens on the camera that squeezes a highly distorted 180° field of view onto the 65 mm IMAX film. The lens is aligned below the center of the frame and most of the bottom half of the circular field falls beyond the edge of the film. The part of the field that would fall below the edge of the dome is masked. When filming, the camera is aimed upward at an angle that matches the tilt of the dome. When projected through a matching fisheye lens onto a dome, the original panoramic view is recreated. OMNIMAX premiered in 1973 showing ‘Voyage to the Outer Planets’ (produced by Graphic Films) and ‘Garden Isle’ (by Roger Tilton Films) on a double bill. IMAX has since renamed the system IMAX Dome. However, some theatres continue to call it OMNIMAX.

OMNIMAX theatres inhabit theme parks and North American museums, particularly those with a scientific focus, where the technical aspects of the system may be highlighted as part of the attraction. The projection room is often windowed to allow public viewing and accompanied by informational placards like other exhibits. The screen may be a permanent fixture, such as at the St. Louis Science Center, Boston’s Museum of Science, and Birmingham, Alabama’s McWane Science Center; or lowered and raised as needed, such as at the Science Museum of Minnesota (where it shares an auditorium with a standard IMAX screen). Before the feature begins, the screen can be backlit to show the speakers and girders behind it. While the majority of museum installations focus on educational and documentary films, on special occasions, entertainment films are also shown, such as ‘Charlie and the Chocolate Factory’ at the Oregon Museum of Science and Industry. The largest in North America are at Liberty Science Center in Jersey City, and the Telus World of Science in Vancouver, both of which have 88 feet (27 m) dome screens.

To create the illusion of depth, the IMAX 3D process uses separate camera lenses to represent the left and right eyes. The two lenses are separated by an interocular distance of 64 mm (2.5 in), the average distance between a human’s eyes. Each lens feeds a separate roll of film. By projecting the two films simultaneously, viewers experience seeing a 3D image on a 2D screen. The IMAX 3D camera weighs over 113 kg (250 lb). One method of creating the 3D illusion involves polarizing the light from the two images. During projection, the left and right eye images are linearly polarized as they are projected. Eyeglasses with right and left lenses polarized to match the projection present each eye with just the image intended for that eye since the polarization cancels out the other eye’s image. Alternatively the two projectors take turns displaying each frame (while one projector’s image is displayed, the other is blocked) at an effective rate of 48 frames per second. The viewer dons LCD shutter glasses that contain LCD panels that block or transmit light in each eye in sync with the projector, such that each eye only sees the image intended for it.

Variations on IMAX included the 48 frames per second IMAX HD process, which sought to reduce strobing and offer higher definition by doubling the normal film rate. The IMAX HD system was tested in 1992 at the Canada Pavilion of the Seville ‘Expo ’92’ with the film ‘Momentum.’ Higher production costs, and the high ‘wear-and-tear’ on the prints and projectors, doomed the IMAX HD system, but, not before many theaters had been retrofitted to project at 48 frames, especially in Canada, in order to play ‘Momentum.’ In the 1990s theme parks in Thailand, Germany, and Las Vegas used IMAX HD for their Motion Simulator rides. The Disney parks attraction ‘Soarin’ Over California’ features a modification of both IMAX HD and IMAX Dome, projecting in 48 frames per second. The doubled IMAX HD frame rate means that each IMAX HD reel lasts half as long, and the logistical implications of this reach throughout the film production chain. IMAX production by default is at least 3 to 5 times more expensive than common 35mm production. The further increase in IMAX HD has prevented significant adoption.

Because the cost and production of 70mm film and projectors are costly and difficult to mass produce, IMAX debuted a digital projection system in 2008. It uses two projectors that can present either 2D or 3D content in DCI (Digital Cinema Initiatives, a joint venture of major motion picture studios, formed to establish a standard for digital cinema systems) or IMAX digital format (which in itself is a superset of DCI). IMAX digital, until 2012, used 2K-resolution (2048×1152) Christie projectors with Texas Instruments Digital Light Processing technology alongside parts of IMAX’s proprietary technologies. The two 2K images are projected over each other, producing an image that is potentially brighter 2K digital cinema.

The digital installations have caused some controversy, as many theaters have branded their screens as IMAX after merely retrofitting standard auditoriums with IMAX digital projectors. The screen sizes in these auditoriums are much smaller than those in the purpose-built auditoriums of the original IMAX format. These theaters charge the same premium pricing as the purpose-built IMAX theaters, resulting in consumer confusion. IMAX marketing makes no distinction between the new smaller digital installations and the original format. Another disadvantage is a lower resolution than normal IMAX film, estimated to be about 12,000×8,700 theoretical pixels. Some reviewers also note that the approach to using dual 2K projectors does not produce an image quality higher than a single 4K (4096×2304) projector system, which are available for some non-IMAX theaters.

In 2012, IMAX announced that it had selected Barco as the primary supplier of projectors for the next 7 years. IMAX began testing a new 4K laser-projection system, based on patents licensed from Eastman Kodak. Like the film and digital systems, it uses two projectors but it has been said to improve over the smaller digital screens to allow films to be shown on screens 120 feet wide or more. The laser projector will be available to exhibitors in 2013-2014.

IMAX recently has been moving forward with digital projection with recent success with ‘The Hunger Games’ and ‘The Avengers’ and digital projection has aided in the company’s worldwide growth, especially in Russia and China. Mainly because the system facilitates inexpensive distribution of IMAX features. The company has recently announced that they are re-renovating specially selected locations around the world to present both 70mm analog and digital presentations. To do so, IMAX has developed with another, currently unknown, business partner a rail system that allows the projectors to be moved in and out if there’s either a full-frame film print available or a digital-only release. IMAX says that it will be prepared in time for ‘The Dark Knight Rises’ in the summer of 2012.

In 2011, IMAX announced a 4K 3D digital camera with the similar wide resolution of regular IMAX film cameras. The camera was developed alongside Vision Research and AbelCine, integrating two Phantom 65 engines. A prototype camera was used for the documentary, ‘Born to be Wild’ in which approximately 10% of the finished film was shot with the system. It’s been said that the new digital camera has no intentions of replacing the higher resolution film cameras but can be used in scenes that require a lightweight or relatively small 3D camera in order to film it without issue. Currently while IMAX has completed the production camera and has been placed into service on several films, there are no plans to produce an IMAX film using solely the new digital system.

Before the end of the 1990’s, theatrical features were deemed impossible to run in the IMAX venues at the time, as there was a technical limitation on the size of the film reel where films had to be run around two hours. Originally IMAX and Pixar were considering to re-release ‘Toy Story’ in IMAX3D. But the results of the tests displayed that the render resolution could not match to the size of the IMAX image. Disney’s ‘Fantasia 2000’ was the studio’s first IMAX release and the first theatrical feature to to be presented in IMAX theaters. It was originally planned as a standard theatrical release, but in agreeing with the company to release the film, the IMAX sound system incorporated a multi-channel and multi-layer stereo system for the orchestrated soundtrack, similar to the Fantasound system Walt Disney used for the original film decades ago. The company agreed to Disney’s terms and conditions to gain the exclusive first showings of the film. These included a limited engagement of 4 months and 50% of the box office receipts. Although not all IMAX cinemas were prepared to accept Disney’s terms to present the film. After the IMAX release, a standard 35mm run followed at regular theaters.

Although ‘Fantasia 2000’ had a luke-warm financial run, the critical praise for its use of the IMAX format convinced Disney to put more releases in the giant-screen format in the pipeline. In 2002, IMAX re-issues of ‘Beauty and the Beast’ and ‘The Lion King’ were released in selected theaters. New digital masters were created from the original production files and select scenes of animation were cleaned up to make use of the high resolution IMAX film negatives. ‘Treasure Planet’ was also released in select IMAX theaters and was the first theatrical film to be released in regular and IMAX theaters simultaneously. But all of these releases had underwhelming box office returns and Disney canceled later big-screen re-releases, including ‘Aladdin.’

In 2003, IMAX released its DMR (Digital Media Remastering) process; which allows conventional films to be upconverted into IMAX format. Warner Bros. Pictures especially embraced the format with the two ‘Matrix’ sequels. Since ‘The Prisoner of Azkaban’ in 2004, Warner Bros. began releasing the ‘Harry Potter’ film franchise in IMAX to strong financial success. Also in 2004 the studio released Robert Zemeckis’ motion-capture film ‘The Polar Express’ in IMAX 3D. ‘Polar Express’ became the most successful film to be released in IMAX theatres, producing at least a quarter of the film’s gross of $302 million from less than 100 IMAX screens. Success for Warner Bros. and IMAX followed in later years with ‘I Am Legend,’ ‘Happy Feet,’ and ‘Batman Begins’ and ‘The Dark Knight.’ Progressively other studios became further interested in releasing films in IMAX through the DMR process and have found success through it.

Reviewers have generally praised the results of the DMR blowup process, which are visually and audibly superior to the same films projected in 35mm. But some filmmakers, such as producer Frank Marshall, point out that DMR blowups are not comparable to films created directly in the 70 mm IMAX format, and that directors Ron Howard and George Lucas expected better results (‘Apollo 11’ and ‘Attack of the Clones’ were two of the first films to be upconverted). They note that the decline of Cinerama coincided roughly with its replacement by a simpler, cheaper, technically inferior version, and view DMR with alarm. IMAX originally reserved the phrase ‘the IMAX experience’ for true 70 mm productions, but now allows its use on DMR productions as well.

Some recent features have employed IMAX cameras for selected scenes, however no full-length feature film has yet been shot entirely using IMAX cameras due to the numerous difficulties presented with the format – the cameras are much larger and heavier than standard cameras and as they are noisier it makes dialogue recording difficult. The cameras have short film loads ranging from 30 seconds to at most three minutes, and the cost of the film stock is much greater than standard 35mm film.

‘The Dark Knight’ featured six sequences (a total of 30 minutes) shot using IMAX. According to the film’s press notes, this was the ‘first time ever that a major feature film has been even partially shot using IMAX cameras.’ Even before Dark Knight, Nolan had wanted to shoot a film in the IMAX format, and he also used it for ‘quiet scenes which pictorially we thought would be interesting.’ Nolan said that he wished that it were possible to shoot the entire film in IMAX: ‘if you could take an IMAX camera to Mount Everest or outer space, you could use it in a feature movie.’ In addition, Nolan chose to edit some of the IMAX sequences using the original camera negative, which by eliminating generation loss, raised the film resolution of those sequences up to 18 thousand lines. When the film opened in 94 IMAX venues in 2008, all of them were sold out for the opening weekend.

A year later, director Michael Bay was inspired by IMAX’s use in ‘The Dark Knight’ to feature big-screen sequences in ‘Transformers: Revenge of the Fallen.’ The film’s co-writer Roberto Orci suggested that the IMAX footage would be 3D, but Bay later said that considering himself an ‘old school’ filmmaker, he found 3D gimmicky and added that shooting in IMAX was easier than using stereoscopic cameras. The IMAX version of the film, in the end, contained almost ten minutes of IMAX-filmed footage out of the two and a half hour film. Bay later partially filmed the third Transformers film, ‘Dark of the Moon’ in 3D but without IMAX.

Two years later, Brad Bird’s ‘Mission: Impossible – Ghost Protocol’ had approximately 30 minutes of footage shot using IMAX cameras. Bird believed that using IMAX format would bring back ‘a level of showmanship’ to the presentation of Hollywood films, which he believes the industry has lost due to its emphasis on screening films in multiplexes as opposed to grand theaters, and vetoing ‘first runs’ in favor of wider initial releases. He also added that the IMAX format offered the viewer more immersion than digital 3D due to its brighter, higher quality image, which is projected on a larger screen, without the need for specialized glasses.

Like with ‘The Dark Knight,’ Christopher Nolan decided to film sequences of the sequel, ‘The Dark Knight Rises,’ in 70mm IMAX. Nolan elected not to film in 3-D and stated that he intends to focus on improving image quality and scale using the IMAX format. In a Hollywood record, the film will feature over an hour of footage shot in IMAX. But because of the considerable noise dialogue had to be dubbed when shot with IMAX cameras.


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