Editing IMAX (section)

=== Film stock ===

The IMAX format is generically called "15/70" film, the name referring to the 15 sprocket holes or perforations per frame. The film's bulk and weight require horizontal platters, rather than conventional vertically mounted film reels. IMAX film is fed through the projector horizontally,<ref>{{cite web|last=Brain |first=Marshall |url=https://entertainment.howstuffworks.com/imax1.htm |title=Howstuffworks 'How IMAX Works' |date=August 3, 2001 |publisher=Howstuffworks.com | access-date=August 14, 2020}}</ref> and the film is drawn from the inner circumference of the platter, not from the outer circumference like in conventional film reels. A system is in place to keep the film in the outer circumference from flying outwards due to centrifugal force while the platter is spinning. IMAX film is shipped to theaters in several small reels that are spliced into one continuous length that is then wound into a platter, a process that may take hours to complete. Films may be several kilometers in length: ''Avatar'', which was 2:45 hours in duration, was close to {{convert|16|km|abbr=on|sp=us}} long. Platters are handled using special forklifts.<ref name="auto1">{{cite web|url=https://www.desmoinesregister.com/story/entertainment/movies/2015/12/16/facts-blank-dome-imax/77427476/|title=10 facts about Des Moines' Blank IMAX|first1=Courtney|last1=Crowder|first2=Jessica|last2=Knight|website=Des Moines Register}}</ref>  IMAX platters range from {{convert|1.2|to|1.83|m|ft|abbr=on|sp=us}} diameter to accommodate 1 to 2.75 hours of film. Platters with a 2.5 hour feature film weigh {{convert|250|kg|lb|abbr=on|sp=us}}. IMAX uses ESTAR-based print film<ref>Kodak's trade name for biaxially oriented PET film</ref> in their 15/70 rolling-loop film projection systems. ESTAR-based print film provides greater precision. The chemical development process does not change the size or shape of ESTAR print film, and IMAX's pin registration system (''especially that of the camera mechanism'') does not tolerate either [[sprocket]]-hole or film-thickness variations, but the film can still swell or shrink under varying temperature and humidity. This requires projection booths to be kept at a temperature of between 20 and 23.8&nbsp;°C and a humidity of 50%.<ref name="auto1"/> The film is too large to be moved using its sprockets,<ref name="auto2">{{cite web|url=https://entertainment.howstuffworks.com/imax.htm|title=How IMAX Works|date=August 3, 2001|website=HowStuffWorks}}</ref> so they are instead used for registration, to aid in aligning the film. A feature film platter can cost {{US$|36000|link=yes}} to print. The camera negative is actually 65&nbsp;mm film stock, but it runs horizontally and with 15 perforations per frame.<ref name="auto">{{cite web|url=https://www.redsharknews.com/technology-computing/item/1754-the-staggering-size-and-scale-of-imax|title=The staggering size and scale of IMAXr|website=Redsharknews.com}}</ref> The camera, like the projector, has a vacuum system; this makes the camera noisy, forbidding the [[sync-sound]] recording of quiet scenes. The camera has enough film for three minutes of shooting. The large frame of the film also imposes optical limitations such as an extremely shallow [[depth of field]] when shooting with an open aperture.<ref>{{cite web|url=https://ymcinema.com/2020/03/10/imax-filmmaking-what-is-it-like-to-shoot-on-an-imax-film-camera/|title=IMAX Filmmaking: What is it like to Shoot on an IMAX Film Camera?|first=Yossy|last=Mendelovich|website=Ymcinema.com|date=March 10, 2020}}</ref>