Editing Negative pulldown

{{Short description|Manner of exposing motion picture film that determines aspect ratio}}
{{tone|date=March 2023}}

[[Image:4 perf 3 perf and 2 perf 35 mm film compared.png|right|thumb|300px|A comparison of 4-perf, 3-perf and 2-perf 35&nbsp;mm film formats]]

'''Negative pulldown''' is the manner in which an image is exposed on a [[film stock]], described by the number of [[film perforations]] spanned by an individual frame. It can also describe whether the image captured on the negative is oriented horizontally or vertically.  Changing the number of exposed perforations allows a [[cinematographer]] to change both the [[aspect ratio (image)|aspect ratio]] of the image and the size of the area on the film stock that the image occupies (which affects image clarity).

The most common negative pulldowns for [[35 mm movie film|35&nbsp;mm film]] are 4-perf and 3-perf, the latter of which is usually used in conjunction with [[Super 35]]. 2-perf, used in [[Techniscope]] in the 1960s, is enjoying a slight resurgence due to the birth of [[digital intermediate]] techniques eliminating the need for optical lab work. Vertical pulldown is overwhelmingly the dominant axis of motion in cinematography, although horizontal pulldown is used in [[IMAX]], [[VistaVision]], and in [[135 film|35&nbsp;mm]] consumer and professional [[still camera]]s.

== Usage of various formats ==
=== History ===
The majority of 35&nbsp;mm film systems, [[camera]]s, [[telecine]] equipment, [[optical printer]]s, or [[Movie projector|projector]]s, are configured to accommodate the 4-perf system; each frame of 35&nbsp;mm is 4 perforations long. 4-perf was (and remains) the traditional system, and the majority of projectors are based on 4-perf, because 4 perforations is the amount needed per frame vertically in order to have enough negative space for a roughly squarish image, which became the [[silent film]] standard [[Aspect ratio (image)|aspect ratio]] of 1.33:1. 

Later, when the film industry was facing the perceived threat of obsolescence to [[television]], universally a 1.33:1 aspect ratio at the time (and remained so in many countries until the introduction of [[Digital Television|DTV]]), studios started experimenting with various competing widescreen formats.

== Current practice ==
Eventually, aspect ratios of 1.85:1 in [[North America]] and 1.66:1 in [[Europe]] became standard for 35&nbsp;mm productions shot with normal non-[[anamorphic]] lenses. However, the aspect ratio for these films is not created within the camera itself but is achieved during projection by placing a cropping device, known as an aperture mask, over the film. As a result, most films are shot in full-screen format—commonly, though inaccurately, referred to as 1.33:1 but actually 1.37:1 due to the inclusion of soundtracks—while being composed for aspect ratios such as 1.85:1 or 1.66:1. These films are then cropped to the desired aspect ratio during projection. Consequently, a significant portion of the film is unused, as the cropped top and bottom sections are typically not intended to be displayed unless the film was specifically protected for full-screen presentation. The 3-perf and 2-perf systems are employed only during the origination and post-production transfer stages.

==35 mm==
===2-perf===
{{main|Techniscope}}

2-perf camera systems use 2 perforations per frame on 35&nbsp;mm film with an aspect ratio close to 2.39:1; the aspect ratio used in [[anamorphic]] prints. It was first proposed conceptually around 1930, but was not put into practice until 1961, when [[Techniscope]] was developed at [[Technicolor]]'s Italian branch. It has recently been brought up again with the advent of higher quality, lower grain [[film stock]]s as well as [[digital intermediate]] post-production methods which eliminate optical blowups and thus improve quality. While in the recent past, some companies have offered custom conversions of camera equipment to 2-perf, it appears that camera manufacturers are now poised to support the format. [[Arri]] made 2-perf movement blocks for their [[Arricam]] and [[Arriflex 235]] cameras available for rental in March 2007.<ref>Arri advertisement, ''British Cinematographer'', March 2007, p. 2.</ref> [[Aaton]]'s [[Aaton Penelope|Penelope]] camera, released in October 2008, was the first camera specifically designed for 2-perf usage (as well as 3-perf).

===3-perf===
{{main|Super 35}}
In the early 1980s, Swedish cinematographer [[Rune Ericson]] collaborated with [[Panavision]] on the concept of creating a 3-perf mechanism for motion picture cameras.<ref>{{Cite web |url=http://www.svenskfilmdatabas.se/en/item/?type=person&itemid=61955 |title=Rune Ericson biography |website=The Swedish Film Database |access-date=2016-09-20}}</ref> The 3-perf system, achieved by altering the camera gate and shutter mechanism, reduces film wastage by using frames that are 3 perforations high instead of the standard 4-perforations. <ref>This sentence has been corrected from its original version 'This results in an aspect ratio of approximately 1.78:1, which closely aligns with the widescreen television aspect ratio of 1.85:1' If correction shouldn't have happened, please re-edit and remove this, if it is correct and rightly happened, please remove this</ref> This results in an aspect ratio of approximately 1.85:1, which closely aligns with the widescreen television aspect ratio of 1.78:1, thereby minimizing image loss outside this aspect ratio. Due to the smaller frame size, the camera operates about 25% slower, leading to a 25% reduction in film stock usage. Additionally, the camera operates more quietly because less film passes through the mechanism per frame. The [[Super 35]] variant of 3-perf also provides a larger negative area, which can help offset the increase in grain when using higher-speed film stocks.

In the late 1990s, cinematographer [[Vittorio Storaro]] proposed a film standard known as [[Univisium]] (also called Univision), which advocated for 3-perf Super 35 to create a 2.00:1 aspect ratio.

=== Disadvantages of 3-perf and 2-perf ===
One disadvantage of 3-perf and 2-perf is found when projected theatrically, as it needs to be transferred back to a 4-perf system. This typically involves a [[film print]] with black cropping on the print itself in order to fit the image onto a 4-perf frame – encountering the same wastage problem as before.  Even so, the amount of film shot on a production is much greater than the length of the final film, so 3-perf or 2-perf are still viable cost-saving options for production.  Generally, 3-perf is most frequently used for [[widescreen]] television productions shot on film, as film is developed and then transferred to [[Videotape|video]], rendering projection incompatibilities irrelevant. Recently, this process has become popular with big-budget motion picture production, due to the advent of the [[digital intermediate]] process. The negative is scanned to high resolution (usually HD, 2K or 4K ([[digital cinema]])) digital files, colour graded, and ultimately printed back to standard 4-perf for projection. At some point in the future, the final 4-perf print will become unnecessary assuming the cinema distribution and projection chain become fully digital.

3-perf and 2-perf pose minor problems for visual effects work. The area of the film in 4-perf work that is not projected nonetheless contains picture information which is useful for such visual effects tasks as 2D and 3D tracking.{{Citation needed|date=October 2015}} This mildly complicates certain visual effects efforts for productions using 3-perf and 2-perf.

[[File:VistaVision_8_perf_35_mm_film.png|right|thumb|300px|A VistaVision 35&nbsp;mm frame, marked for a 1.85:1 crop]]

=== VistaVision ===
{{main|VistaVision}}
'''VistaVision''' is a higher resolution, [[widescreen]] variant of the [[35 mm movie film|35&nbsp;mm motion picture film]] format which was created by [[Paramount Pictures]] in 1954. It uses a horizontal, 8 perforation 35&nbsp;mm image, similar to that used in [[135 film]] for [[photography|still photography]]. Paramount did not use [[anamorphic]] processes such as [[CinemaScope]] but refined the quality of their flat widescreen system by orienting the 35&nbsp;mm negative horizontally in the camera gate and shooting onto a larger area, which yielded a finer-grained projection print.

==70 mm==
{{main|70 mm film}}
===Standard 65 mm (5/70) (Todd-AO, Super Panavision)===
* spherical lenses
* 5 perforations/frame
* 42 frames/meter (12.8 frame/ft)
* 34.29 meters/minute (112.5&nbsp;ft/minute)
* vertical pulldown
* 24 frames/second
* ''camera aperture'': 52.48 by 23.01&nbsp;mm (2.066 by 0.906 in)
* ''projection aperture'': 48.56 by 20.73&nbsp;mm (1.912 by  0.816 in)
* 305&nbsp;m (1000&nbsp;feet), about 9 minutes at 24 frame/s = 4.5&nbsp;kg (10 pounds) in can
* ''aspect ratio'': 2.2:1

===Ultra Panavision 70 (MGM Camera 65)===
{{main|Ultra Panavision 70}}
''Same as Standard 65&nbsp;mm except''
* Shot with special anamorphic adapter in front of lens
* 1.25× squeeze factor, projected aspect ratio 2.76:1

===Showscan===
{{main|Showscan}}
''Same as Standard 65&nbsp;mm except''
* 60 frames per second

===IMAX (15/70)===
{{main|IMAX}}
* spherical lenses
* 15 perforations per frame
* horizontal movement, from right to left (viewed from base side)
* 24 frames per second
* ''camera aperture'': 70.41 by 52.63&nbsp;mm (2.772 by 2.072 in)
* ''projection aperture'': at least 2&nbsp;mm (0.080&nbsp;in) less than camera aperture on the vertical axis and at least 0.4&nbsp;mm (0.016&nbsp;in) less on the horizontal axis
* ''aspect ratio'': 1.35:1 (camera), 1.43:1 (projected)

===Dynavision (8/70) (Also known as Iwerks 8/70)===
* fisheye or spherical lenses, depending on if projecting for a dome or not
* vertical pulldown
* 24 or 30 frames per second
* ''camera aperture'': 52.83 by 37.59&nbsp;mm (2.080 by 1.480 in)

==See also==
* [[List of film formats]]

==References==
{{reflist}}
{{refbegin}}
* [https://web.archive.org/web/20080118094257/http://www.arri.de/prod/cam/technology_3_perforation.htm 3 PERFORATION - SAME IMAGE QUALITY AT LOWER COSTS]
* [https://web.archive.org/web/20060713061542/http://www.aaton.com/products/film/35/3perf.php The future of 35mm filmmaking: standard rawstock but 3perf/picture instead of 4perf.]
{{refend}}

==External links==
* [[wikibooks:Movie Making Manual/Post-production/Telecine|Movie Making Manual wikibook article on Telecine]] including a list of facilities that can telecine 2-perf

{{DEFAULTSORT:Negative Pulldown}}
[[Category:Film and video technology]]