70 mm film
[2] The use of anamorphic Ultra Panavision 70 lenses squeezes an ultra-wide 2.76:1 aspect ratio horizontally into that 2.2:1 imaging area.
To this day, Ultra Panavision 70 produces the widest picture size in the history of filmmaking; surpassed only by Polyvision, which was only used for 1927's Napoléon.
Cinerama employed three 35 mm film projectors running in synchronism to project a wide (2.6:1) image onto a deeply curved screen.
Although the results were impressive, the system was expensive, cumbersome and had some serious shortcomings due to the need to match up three separate projected images.
The Todd-AO format was originally intended to use a deeply curved Cinerama-type screen but this failed to survive beyond the first few films.
However Todd-AO has six channels instead of the four of Cinemascope and due to the wider stripes and faster film speed provides superior audio quality.
It had another resurgence in the mid-2010s with the release of The Master (2012), The Hateful Eight (2015) and Dunkirk (2017), with a small number of venues getting temporary or permanent 70 mm film projectors in order to be able to screen these titles.
[4] Quentin Tarantino, in particular, led a successful campaign to have the equipment required to show The Hateful Eight in Ultra Panavision installed in 100 cinemas worldwide.
These enlargements often provided richer colors, and a brighter, steadier and sharper (though often grainier) image, but the main benefit was the ability to provide 6-channel stereophonic sound as most theaters before the mid-70s (before the advent of Dolby A) were screening 35 mm prints with single channel monaural sound.
[1] However these "blow-ups" rarely used the full six channels of the Todd-AO system and instead used the four-track mixes made for 35 mm prints, the additional half-left and half-right speakers of the Todd-AO layout being fed with a simple mix of the signals intended for the adjacent speakers (known as a "spread") or simply left blank.
[12] This layout came to be known as "5.1" (the "point one" is the low-frequency enhancement channel) and was subsequently adopted for digital sound systems used with 35 mm.
Among some of the more recent 70 mm blow-up titles are Paul Thomas Anderson's Inherent Vice (2014)[1] and Phantom Thread (2017), Patty Jenkins's Wonder Woman (2017),[13] and Steven Spielberg's Ready Player One (2018).
An anamorphic squeeze combined with 65 mm film allowed for extremely wide aspect ratios to be used while still preserving quality.
Since the 1990s, a handful of films (such as Spider-Man 2) have used 65mm for this purpose, but the usage of digital intermediate for compositing has largely negated these issues.
Digital intermediate offers other benefits such as lower cost and a greater range of available lenses and accessories to ensure a consistent look to the footage.
The Dynavision and Astrovision systems each use slightly less film per frame and vertical pulldown to save print costs while being able to project onto an IMAX screen.
The system was developed by Allan Silliphant and Chris Condon of StereoVision International Inc., which handled all technical and marketing aspects on a five-year special-royalty basis with Warner Bros.
One of the few producers of 70 mm films for Cinema 180 was the German company Cinevision (today AKPservices GmbH, Paderborn).
