|
Sin embargo, Eastman fue la primera gran empresa que lanzó la producción en masa de estos componentes, cuando en 1889 notó que la emulsión de solución gelatinosa de bromuro podía ser aplicada a esta base clara eliminado así el papel.<ref>Mees, C. E. Kenneth (1961). ''From Dry Plates to Ektachrome Film: A Story of Photographic Research''. Ziff-Davis Publishing. pp. 15-16.</ref>
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Con la aparición de la pelicuula flexible, [[Thomas Alva Edison]] rapidamente empezó a trabajar en su invención, el [[Kinetoscopio]], el cual fue exhibido por primera vez en el Instituto de Arte y Ciencia de Brooklyn en [[May 9]], [[1893]].<ref>Robinson, David (1997). ''Desde Peepshow hasta el palacio: El nacimiento del cine americano''. New York and Chichester, West Sussex: Columbia University Press; pp. 39–40. ISBN 0-231-10338-7</ref> El kinetoscopio era un sistema de proyección secuencual planeado para ser visto por una persona a la vez.<ref name="hone">''Kodak Motion Picture Film (H1)'' (4th ed). Eastman Kodak Company. ISBN 0-87985-477-4</ref> Edison, junto con su asistente W.K.L. Dickson, continuó con su trabajo e inventó el [[Kinetoscopio#Kinetofono|Kinetófono]], el cual combinaba el Kinetoscopio con el cilindro de Edison, el [[fonógrafo]]<!--. Beginning in March 1892, Eastman and then, from April 1893 into 1896, New York's Blair Camera Co. supplied Edison with 1 9/16–inch filmstock that would be trimmed and perforated at the Edison lab to create 35 mm gauge filmstrips (at some point in 1894 or 1895, Blair began sending stock to Edison that was cut exactly to specification).<ref>Spehr, Paul C. (2000). ''Unaltered to Date: Developing 35mm Film'', in ''Moving Images: From Edison to the Webcam'', ed. John Fullerton and Astrid Söderbergh Widding. Sydney: John Libbey & Co; pp. 3–28 (pp. 11–14). ISBN 1-86462-054-4</ref> Edison's aperture defined a single frame of film at 4 perforations high.<ref name="katz">Katz, Ephraim. (1994). ''The Film Encyclopedia'' (2nd ed.). HarperCollins Publishers. ISBN 0-06-273089-4.</ref> Edison claimed exclusive patent rights to his design of 35 mm motion picture film, with four sprocket holes per frame, forcing his only major filmmaking competitor, [[American Mutoscope and Biograph Company|American Mutoscope & Biograph]], to use a 68 mm film that used friction feed, not sprocket holes, to move the film through the camera. A court judgment in March 1902 invalidated Edison's claim, allowing any producer or distributor to use the Edison 35 mm film design without license. Filmmakers were already doing so in Britain and Europe, where Edison had failed to file patents.<ref>{{cite book | first = Charles | last = Musser | title = The Emergence of Cinema: The American Screen to 1907 | location = Berkeley, Cal. | publisher = University of California Press| year = 1994 | pages = 303-313|id = ISBN 0-520-08533-7}}</ref> A variation developed by the [[Auguste and Louis Lumière|Lumière Brothers]] used a single circular perforation on each side of the frame towards the middle of the horizontal axis.<ref name="lumiere">Lobban, Grant. "Film Gauges and Soundtracks", BKSTS wall chart (sample frame provided). [Year unknown]</ref> It was Edison's format, however, that became first the de facto standard and then, in 1909, the "official" standard of the newly formed [[Motion Picture Patents Company]], a [[trust (19th century)|trust]] established by Edison. Scholar Paul C. Spehr describes the importance of these developments:
<blockquote>
[T]he early acceptance of 35mm as a standard had momentous impact on the development and spread of cinema. The standard gauge made it possible for films to be shown in every country of the world.... It provided a uniform, reliable and predictable format for production, distribution and exhibition of movies, facilitating the rapid spread and acceptance of the movies as a world-wide device for entertainment and communication.<ref>Spehr, Paul C. (2000). ''Unaltered to Date: Developing 35mm Film'', in ''Moving Images: From Edison to the Webcam'', ed. John Fullerton and Astrid Söderbergh Widding; pp. 3–28 (p. 4). Sydney: John Libbey & Co. ISBN 1-86462-054-4</ref>
</blockquote>
The film format was introduced into still photography as early as 1913 (the Tourist Multiple) but first became popular with the launch of the [[Leica]] camera, created by [[Oskar Barnack]] in 1925.<ref>Scheerer, Theo M. (1960). ''The Leica and the Leica System'' (3rd ed). Umschau Verlag Frankfurt Am Main. pp. 7-8.</ref>
===Amateur interest===
The [[petrochemical]] and [[silver]] compounds necessary for the creation of film stock meant from the start that 35 mm filmmaking was to be an expensive hobby with a high [[barrier to entry]] for the public at large. Furthermore, the [[nitrocellulose]] [[film base]] of all early film stock was dangerous and highly flammable, creating considerable risk for those not accustomed to the precautions necessary in its handling. [[Birt Acres]] was the first to attempt an amateur format, creating [[Birtac]] in 1898 by slitting the film into 17.5 mm widths. By the early 1920s, several formats had successfully split the amateur market away from 35 mm — namely [[28 mm film|28 mm]] (1912), [[9.5 mm film|9.5 mm]] (1922), [[16 mm]] (1923), and Pathe Rural, a safety 17.5 mm format (1926). Eastman Kodak's 16 mm format won the amateur market and is still widely in use today, mainly in the Super 16 variation which remains very popular with professional filmmakers. The 16 mm size was specifically chosen to prevent third-party slitting, as it was very easy to create 17.5 mm stock from slitting 35 mm stock in two. It also was the first major format only be released with the non-flammable [[cellulose diacetate]] (and later [[cellulose triacetate]]) "safety film" base. This amateur market would be further diversified by the introduction of [[8 mm film]] in 1932, intended for amateur filmmaking and "home movies".<ref name="tafi">Slide, Anthony (1990). ''The American Film Industry: A Historical Dictionary''. Limelight (1st ed). ISBN 0-87910-139-3</ref> By law, both 16 mm and 8 mm gauge stock (as well as 35 mm films intended for non-theatrical use) had to be manufactured on safety stock. The effect of these gauges was to essentially make the 35 mm gauge almost the exclusive province of professional filmmakers, a divide which mostly remains to this day.
==How film works==
{{Mergeto|Film stock|Talk page|date=February 2007}}
{{Main|Photographic film|Color film (motion picture)|Exposure (photography)|Film base}}
Inside the photographic emulsion are millions of light-sensitive [[silver halide]] crystals. Each crystal is a compound of [[silver]] plus a [[halogen]] (such as [[bromine]], [[iodine]] or [[chlorine]]) held together in a cubical arrangement by electrical attraction. When the crystal is struck with light, free-moving silver ions build up a small collection of uncharged atoms. These small bits of silver, too small to even be visible under a microscope, are the beginning of a [[latent image]]. [[Photographic processing|Developing]] chemicals use the latent image specs to build up density, an accumulation of enough metallic silver to create a visible image.<ref>Upton, Barbara London with Upton, John (1989). ''Photography'' (4th ed). BL Books, Inc./Scott, Foresman and Company. ISBN 0-673-39842-0.</ref>
[[Imagen:35mm-undevel.jpg|thumb|left|A short strip of undeveloped 35 mm film.]]The emulsion is attached to the [[film base]] with a transparent adhesive called the subbing layer. Below the base is an undercoat called the antihalation backing, which usually contains absorber dyes or a thin layer of silver or carbon (called rem-jet on color negative stocks). Without this coating, bright points of light would penetrate the emulsion, reflect off the inner surface of the base, and reexpose the emulsion, creating a halo around these bright areas. The antihalation backing can also serve to reduce static buildup, which was a significant problem with old black and white films. The film, which runs through the camera at 18 inches per second, could build up enough static electricity to actually cause a spark bright enough to expose the film; antihaliation backing solved this problem. Color films have three layers of silver halide emulsions to separately record the red, green and blue information. For every silver halide grain there is a matching color coupler grain. The top layer contains blue-sensitive emulsion, followed by a yellow filter to cancel out blue light - after this comes a green sensitive layer followed by a red sensitive layer.
Just as in black-and-white, the first step in color development converts exposed silver halide grains into metallic silver — except that an equal amount of color dye will be formed as well. The color couplers in the blue-senstitive layer will form yellow dye during processing the green layer will form magenta dye and the red layer will form cyan dye. A bleach step will convert the metallic silver back into silver halide, which is then removed along with the unexposed silver halide in the fixer and wash steps, leaving only color dyes.<ref>Malkiewicz, Kris and Mullen, M. David ASC (2005) ''Cinematography'' (3rd ed). Simon Schuester. pp. 49-50. ISBN 0-7432-6438-X</ref>
In the 1980s Eastman Kodak invented the [[Tabular-grain film|T-Grain]], a synthetically manufactured silver halide grain that had a larger, flat surface area and allowed for greater light sensitivity in a smaller, thinner grain. Thus Kodak was able to break the [[Catch-22 (logic)|Catch-22]] of higher speed (greater light sensitivity — see [[film speed]]) means larger grain and more "[[Film grain|grainy]]" images. With T-Grain technology, Kodak refined the grain structure of all their "EXR" line of motion picture film stocks<ref>Probst, Christopher (May 2000). "Taking Stock" Part 2 of 2 ''American Cinematographer Magazine'' ASC Press. pp. 110-120</ref> (which was eventually incorporated into their "MAX" still stocks). Fuji films followed suit with their own grain innovation, the tabular grain in their SUFG (Super Unified Fine Grain) SuperF negative stocks, which are made up of thin hexagonal tabular grains.<ref>Holben, Jay (April 2000). "Taking Stock" Part 1 of 2 ''American Cinematographer Magazine'' ASC Press. pp. 118-130</ref>
===Other common types of photographic films===
In addition to black & white and color negative films, there are black & white and color [[reversal film]]s, which when developed create a positive ("natural") image that is projectable. There are also films sensitive to non-visible wavelengths of light, such as [[Infrared photography|infrared]].
==Attributes==
{{Mergeto|Film stock|Talk page|date=February 2007}}
===Color===
{{main|Color film (motion picture)}}
Originally, film was a strip of cellulose nitrate coated with black-and-white photographic [[emulsion]].<ref name="hone" /> Early film pioneers, like [[D. W. Griffith]], color [[film tinting|tinted or toned]] portions of their movies for dramatic impact, and by 1920, 80 to 90 percent of all films were tinted.<ref>{{cite book | first = Richard | last = Koszarski | title = An Evening's Entertainment : The Age of the Silent Feature Picture, 1915-1928 | location = | publisher = University of California Press | year = 1994 | pages = 127|id = ISBN 0-520-08535-3 }}</ref> The first successful natural color process was Britain's [[Kinemacolor]] (1908-1914), a two-color additive process that used a rotating disk with red and green filters in front of the camera lens and the projector lens.<ref>{{cite book | first = Patrick | last = Robertson | title = Film Facts | location = New York | publisher = Billboard Books | year = 2001 | pages = 166 | id = ISBN 0-8230-7943-0 }}</ref><ref>Hart, Martin. (1998) [http://www.widescreenmuseum.com/oldcolor/kinemaco.htm "Kinemacolor: The First Successful Color System"] Widescreen Museum. Retrieved July 8, 2006</ref> But any process that photographed and projected the colors sequentially was subject to color "fringing" around moving objects, and a general color flickering.<ref>Hart, Martin (May 20, 2004). [http://www.widescreenmuseum.com/oldcolor/kinemacolortoeastmancolor.htm "Kinemacolor to Eastmancolor: Faithfully Capturing an Old Technology with a Modern One"] Widescreen Museum. Retrieved July 8, 2006</ref>
In 1916, William Van Doren Kelley produced the first commercially successful American color system using 35mm film called [[Prizma]]. Initially a system that used frame sequential photography and projectected through additive synthesis, Prizma was refined to bi-pack photography, with two strips of film (one senstitized for red and one for blue) threaded as one through the camera. The method of projection was also changed: each record was printed and processed on [[Duplitized film|duplitized stock]], creating a successful subtractive color process. This basic principle behind color photography set the standard for many later successful color formats, such as [[Multicolor]], Brewster Color, and [[Cinecolor]].
Although color was available for years prior, color in Hollywood feature films became popular with [[Technicolor]], whose main advantage was quality prints in shorter time than its competitors. In its earliest conception, Technicolor was a 2-color system, recording red and green. 1922's ''[[Toll of the Sea]]'' was the first film printed in their subtractive color system. Unlike Kinemacolor, which recorded color frame-sequentially, Technicolor's camera recorded red and green frames simultaneously through a beam splitting prism onto one strip of film. Two prints on half-width stock were processed from this negative, and one was toned red, and the other toned green. The two strips were then cemented together, forming a single strip similar to duplitized film.
In 1928, Technicolor introduced imbibition printing (similar to [[lithography]]) that streamlined the process. Using two matrices coated with hardened gelatin in a relief image, thicker where the image was darker, aniline color dyes were transferred onto a third, blank strip of film.
In 1934, William T. Crispinel and Alan M. Gundelfinger revived the [[Multicolor]] process under the company name [[Cinecolor]]. Cinecolor enjoyed large success in animation and low-budget pictures, largely due to its inexpense and good image results. But while Cinecolor used the same duplitized stock method as Prizma and Multicolor, its main advange was inventing processing machines that could do larger quantities of film in a shorter time.
Technicolor re-emerged with a three-color process for cartoons in 1932, and live action in 1934. Using a beam-splitter prism behind the lens, this camera incorporated three individual strips of black and white film, each one behind a filter of one of the [[primary colors]] (red, green and blue), allowing the full color spectrum to be recorded.<ref name="widetech">Hart, Martin (2003). [http://www.widescreenmuseum.com/oldcolor/technicolor1.htm "The History of Technicolor"] Retrieved July 7, 2006</ref> A printing matrix with a hardened gelatin relief image was made from each negative, and the three matrices transferred color dye onto a blank film to create the print.<ref>Sipley, Louis Walton. (1951). ''A Half Century of Color'' The Macmillan Company, New York.</ref>
In 1950 Kodak announced the first Eastman color 35 mm negative film (along with a complementary positive film) that could record all three primary colors on the same strip of film.<ref>Kodak | Motion Picture Imaging [http://www.kodak.com/US/en/motion/about/chrono1.shtml Chronology of Motion Picture Films] Retrieved July 10, 2006.</ref> An improved version in 1952 was quickly adopted by Hollywood, making the use of tri-strip Technicolor cameras and bi-pack cameras (utilized in two-color systems such as [[Cinecolor]]) obsolete in color cinematography. This "monopack" structure is made up of three separate emulsion layers, one sensitive to red light, one to green and one to blue.
===Safety film===
Although [[Eastman Kodak]] had first introduced [[acetate]]-based film, it was far too brittle and prone to shrinkage, so the very dangerous nitrate-based celluose films, which had to be handled with extreme care or else they were prone to catching fire and exploding, were generally used for motion picture camera and print films. In 1949 Kodak began replacing all of the [[Nitrocellulose|nitrate-based]] films with the safer, more robust [[cellulose triacetate]]-based "Safety" films. In 1950 the [[Academy of Motion Picture Arts and Sciences]] awarded Kodak with a Scientific and Technical [[Academy Award]] ([[Academy Awards|Oscar]]) for the safer triacetate stock.<ref>Internet Movie Database, [http://us.imdb.com/Sections/Awards/Academy_Awards_USA/1950#Academy_Award_of_Merit Academy Awards, USA: 1950].</ref> By 1952, all camera and projector films were triacetate-based.<ref name="tafi" /> Most if not all film prints today are made from synthetic [[polyester]] safety base (which started replacing Triacetate film for prints starting in the early 1990s). However, the downside of [[polyester]] film is that it is extremely strong, and in case of a fault, will stretch and not break (potentially causing damage to the projector and ruining a fairly large stretch of film - 2-3ft or ~2 sec.), and will melt the frames if exposed to the projector bulb for too long. [[Original camera negative]] is still generally made on a triacetate base.
==Common formats==
:''See [[list of film formats]] for a comprehensive table of known formats''
====Academy format====
{{main|Academy ratio}}
In the conventional motion picture format, frames are four perforations tall, with an [[aspect ratio]] of about 1.37:1, 22 mm by 16 mm (0.866" x 0.630"). This is a derivation of the aspect ratio and frame size designated by Thomas Edison (24.89 mm by 18.67 mm or .980" by .735") at the dawn of motion pictures, which was an aspect ratio of 1.33:1.<ref>{{cite book | first = John | last = Belton | title = Widescreen Cinema | location = Cambridge, Mass. | publisher = Harvard University Press | year = 1992 | pages = 17-18|id = ISBN 0-674-95261-8 }}</ref> The first sound features were released in 1926-1927, and while [[Warner Bros.]] was using synchronized phonograph discs, [[Fox Film Corporation|Fox]] placed the soundtrack in an optical record directly on the film, on a strip between the sprocket holes and the image frame.<ref name="early sound">Dibbets, Karel. "The Introduction of Sound". ''The Oxford History of World Cinema''. Oxford University Press: Oxford, 1996.</ref> "Sound-on-film" was soon adopted by the other Hollywood studios. This resulted in an almost square image ratio. To restore a more rectangular image ratio, in 1932 the picture was shrunk slightly vertically (with the line between frames thickened). Hence the frame became 22 mm by 16 mm (.866" by .630") with an aspect ratio of 1.37:1. This became known as the "[[Academy ratio|Academy]]" ratio, named so after the [[Academy of Motion Picture Arts and Sciences]].<ref name="1.37">Hummel, Rob (ed.). ''American Cinematographer Manual'', 8th edition. pp. 18-22. ASC Press: Hollywood, 2001.</ref> Although, since the 1950s the aspect ratio of theatrically released motion picture films has been 1.85:1 (1.66:1 in Europe) or 2.35:1 (2.40:1 after 1970), so the "Academy" ratio was relegated to usage primarily for television. The image area for "TV transmission" is slightly smaller than the full "Academy" ratio at 21 mm by 16 mm (0.816" by 0.612"), which is an aspect ratio of 1.33:1. Hence the "Academy" ratio is often mistakenly referred to as having an aspect ratio of 1.33:1, referring to the TV transmitted area, instead of the actual 1.37:1 ratio of the full "Academy" area.<ref name="1.37" />
====Widescreen====
{{Main|Anamorphic|Aspect ratio (image)|Widescreen}}
The commonly used [[anamorphic widescreen]] format uses a similar four-perf frame, but an anamorphic lens is used on both the camera and projector to produce a wider image, today with an aspect ratio of about 2.39 (more commonly referred to as 2.40:1. The ratio was 2.35:1 — and is still quite often mistakenly referred to as such — until a [[SMPTE]] revision of projection standards in 1970).<ref name="2.39">Hart, Martin.(2000). Widescreen museum [http://www.widescreenmuseum.com/widescreen/apertures.htm "Of Apertures and Aspect Ratios"] Retrieved August 10, 2006.</ref> The image, as recorded on the negative and print, is horizontally compressed (squeezed) by a factor of 2.<ref name="ana">Hora, John. "Anamorphic Cinematography". ''American Cinematographer Manual'', 8th edition. ASC Press: Hollywood, 2001.</ref>
[[Imagen:Film-frames-nba.jpg|thumb|A film which has been "hard matted" to 1.85:1 in-camera. Most non-anamorphic widescreen films, however, are "soft matted" by a mask in the [[movie projector]] gate.]]The unexpected success of the [[Cinerama]] widescreen process in 1952 led to a boom in [[film format]] innovations from both studios and individuals looking to capitalize on audience demand for higher quality, lower cost widescreen images. Before the end of the year, [[20th Century Fox]] had narrowly "won" a race to obtain [[anamorphic]] optics, and began hyping the [[Cinemascope]] technology as early as the production phase.<ref name="scope">Hart, Martin. American Widescreen Museum, [http://www.widescreenmuseum.com/widescreen/wingcs1.htm "Cinemascope Wing 1"]. Retrieved August 10, 2006.</ref> Feeling the need to compete but having little time for research and development, the major studios hit upon an easier solution by May 1953: matte the top and bottom of the frame to create a wider aspect ratio. Paramount Studios began this trend with their aspect ratio of 1.66:1, first used in ''[[Shane (film)|Shane]]'', which was originally shot for [[Academy ratio]].<ref name="crop">Hart, Martin. American Widescreen Museum, [http://www.widescreenmuseum.com/Widescreen/evolution.htm "Early Evolution from Academy to Wide Screen Ratios"]. Retrieved August 10, 2006.</ref> Other studios followed suit with aspect ratios of 1.75:1, 1.85:1 and 2:1. For a time, these various ratios competed, but by 1956, the aspect ratio of 1.85:1 became the "standard" US format. These ''flat'' films are photographed with the full [[Academy ratio|Academy frame]], but are matted (most often with a mask in the theater projector, not in the camera) to obtain the "wide" aspect ratio. This standard, in some European nations, became 1.66:1 instead of 1.85:1.
By September 1953, [[20th Century Fox]] debuted [[Cinemascope|CinemaScope]], the earliest mainstream anamorphic film process, to great success.<ref>Samuelson, David W. (September 2003). "Golden Years". ''American Cinematographer Magazine'' ASC Press pp. 70-77.</ref> It became the basis for a host of "formats", usually suffixed with ''-scope'', which were otherwise identical in specification, although often inferior in optical quality. (Some developments, such as [[Superscope|SuperScope]] and [[Techniscope]], however, were truly entirely different formats.) [[Panavision]] would eventually solve many of the Cinemascope lenses' technical limitations with their own lenses,<ref name="ana" /> and Cinemascope became obsolete in 1967 in favor of Panavision and other third-party manufacturers.<ref name="obsolete">Nowell-Smith, Geoffrey (ed.) ''The Oxford History of World Cinema'', pg. 266. Oxford University Press: Oxford, 1996.</ref>
The 1950s and 1960s saw many other novel processes such as [[Vistavision|VistaVision]], SuperScope, [[Technirama]], and Techniscope, most of which ultimately became obsolete. Vistavision, however, would be revived decades later by [[Lucasfilm]] for special effects work, while a SuperScope variant became the predecessor to the modern [[Super 35]] format popular today.
====Super 35====
{{Main|Super 35 mm film}}
The concept behind Super 35 originated with the Tushinsky Brothers' [[SuperScope]] format, particularly the SuperScope 235 specification from 1956. In 1982, Joe Dunton revived the format for ''[[Dance Craze]]'', and [[Technicolor]] soon marketed it under the name "Super Techniscope" before the industry settled on the name Super 35.<ref name="dunton">Mitchell, Rick. Society of Camera Operators Magazine, [http://www.soc.org/opcam/04_s94/mg04_widescreen.html The Widescreen Revolution: Expanding Horizons — The Spherical Campaign"], Summer 1994. Retrieved August 12, 2006.</ref> The central driving idea behind the process is to return to shooting in the original silent "Edison" 1.33:1 full 4-perf negative area (24.89 mm by 18.67 mm or .980" by .735"), and then crop the frame either from the bottom or the center (like 1.85:1) to create a 2.40:1 aspect ratio (matching that of anamorphic lenses) with an area of 24 mm by 10 mm (.945" by .394"). Although this cropping may seem extreme, by expanding the negative area out perf-to-perf, Super 35 creates a 2.40:1 aspect ratio with an overall negative area of 240 mm² (9.45 in²), only a mere 9 mm² (.35 in²) less than the 1.85:1 crop of the Academy frame (248.81 mm² or 9.80 in²).<ref name="asc">Burum, Stephen H. (ed) (2004). ''American Cinematographer Manual'' (9th ed). ASC Press. ISBN 0-935578-24-2</ref> The cropped frame is then converted at the intermediate stage to a 4-perf anamorphically squeezed print compatible with the anamorphic projection standard. This allows an "anamorphic" frame to be captured with non-anamorphic lenses, which are much more common, less expensive, faster, smaller, and optically superior to equivalent anamorphic lenses.<ref name="asc" /> Up to 2000, once the film was photographed in Super 35, an optical printer was used to anamorphose (squeeze) the image. This optical step reduced the overall quality of the image and made Super 35 a controversial subject among cinematographers, many who preferred the higher image quality and frame negative area of anamorphic photography (especially with regard to [[Film grain|granularity]]).<ref name="asc" /> With the advent of [[Digital intermediate]]s (DI) at the beginning of the 21st century, however, Super 35 photography has become even more popular, since the cropping and anamorphosing stages can be done digitally in-computer without creating an additional optical generation with increased grain. As DI becomes less expensive and more popular, it is likely to render Super 35 optical conversions completely obsolete in the near future.
====3-Perf====
{{Main|Negative pulldown}}
Most motion pictures today are shot and projected using the [[4-perf]]oration format, but cropping the top and bottom of the frames for an aspect ratio of 1.85 or 1.66. In [[television production]], where compatibility with an installed base of 35 mm film projectors is unnecessary, a [[3-perf]] format is sometimes used, giving — if used with [[Super 35]] — the 16:9 ratio used by [[High-definition television|HDTV]] and reducing film usage by 25 percent. Because of 3-perf's incompatibility with standard 4-perf equipment, it can utilize the whole negative area between the perforations ([[Super 35 mm film]]) without worrying about compatibility with existing equipment; the Super 35 image area includes what would be the soundtrack area in a standard print.<ref name="aaton">[[Aaton]], [http://www.aaton.com/products/film/35/3perf.php "3 perf: The future of 35mm filmmaking"]. Retrieved August 10, 2006</ref> All 3-perf negatives require optical or digital conversion to standard 4-perf if a film print is desired, though 3-perf can easily be transferred to video with little to no difficulty by modern [[telecine]] or film scanners. With [[digital intermediate]] increasingly becoming a standard process for post-production, 3-perf has become more popular with productions which would otherwise be averse to an optical conversion stage.<ref name="arri">[[Arri]], [http://www.arri.com/news/newsletter/articles/0357824976/3-perf.htm "3 Perf Conversion Kit for the Arricam System"], Arri Newsletter, March 2002. Retrieved August 10, 2006.</ref>
====VistaVision====
{{main|VistaVision}}
[[Imagen:VistaVision 8 perf 35 mm film.png|thumb|A diagram of the [[VistaVision]] format, affectionately dubbed "Lazy 8" because it is eight [[film perforations|perforations]] long and runs horizontally (laying down).]]The [[VistaVision]] motion picture format was created in 1954 by [[Paramount Pictures]] in order to create a finer-grained negative and print for flat widescreen films.<ref name="vista">Nowell-Smith, Geoffrey (ed.) ''The Oxford History of World Cinema'', pp. 446-449. Oxford University Press: Oxford, 1996.</ref> Similar to [[still photography]], the format uses a camera running 35 mm film horizontally instead of vertically through the camera, with frames that are eight perforations long, resulting in a wider aspect ratio of 1.5:1 and greater detail, as more of the negative area is used per frame.<ref name="asc" /> This format is unprojectable in standard theaters and requires an optical step to squeeze the image into the standard 4-perf vertical 35 mm frame.<ref name="achart">Hart, Douglas C. ''The Camera Assistant: A Complete Professional Handbook''. Focal Press: Boston, 1996.</ref>
While the format was dormant by the early 1960s, the camera system was somewhat revived for visual effects by [[John Dykstra]] at [[Industrial Light and Magic]], starting with ''[[Star Wars]]'', as a means of reducing granularity in the [[optical printer]] by having increased [[original camera negative]] area at the point of image origination.<ref name="starwars">Blalack, Robert and Paul Roth. "Composite Optical and Photographic Effects". ''American Cinematographer Magazine'', July 1977.</ref> Its usage has again declined since the dominance of computer-based visual effects, although it still sees very limited utilization.<ref name="batman">[http://www.fxguide.com/article262.html "Double Negative Breaks Down ''Batman Begins''"]. FXGuide, 2005-07-18. Retrieved August 11, 2006.</ref>
===Perforations===
{{main|Film perforations}}
'''BH perfs:''' Film perforations were originally round holes cut into the side of the film, but as these perforations were more subject to wear and deformation, the shape was changed to that now called the [[Böwe Bell & Howell|Bell & Howell]] (BH) perforation, which has a straight top and bottom edge and outward curving sides. The BH perforation's dimensions are 0.110" (2.79 mm) from the middle of the side curve to opposite top corner by 0.073" (1.85 mm) in height.<ref name="case">Case, Dominic. ''Motion Picture Film Processing''. Boston: Focal Press, 1985.</ref> The BH1866 perforation, or BH perforation with a [[Film perforations#pitch|pitch]] of 0.1866", is the modern standard for negative and internegative films.
'''KS perfs:''' Because BH perfs have sharp corners, the repeated use of the film through intermittent movement projectors creates strain that can easily tear the perforations. Furthermore, they tended to shrink as the print slowly decayed. Therefore, larger perforations with a rectangular base and rounded corners were introduced by [[Kodak]] in 1924 to improve steadiness, registration, durability, and longevity. Known as "Kodak Standard" (KS), they are 0.0780" (1.981 mm) high by 0.1100" (2.794 mm) wide.<ref name="smpte139" /> Their durability makes KS perfs the ideal choice for intermediate and release prints, as well as [[original camera negative]]s which require special use, such as [[high-speed filming]], [[bluescreen]], [[front projection]], [[rear projection]], and matte work. The increased height also means that the image registration was considerably less accurate than BH perfs, which remains the standard for negatives.<ref name="screensound">ScreenSound Australia, [http://www.screensound.gov.au/glossary.nsf/Pages/Perforations?OpenDocument "Technical Glossary of Common Audiovisual Terms: Perforations"]. Retrieved August 11, 2006.</ref> The KS1870 perforation, or KS perforation with a [[Film perforations#pitch|pitch]] of 0.1870", is the modern standard for release prints.
These two perforations have remained by far the most commonly-used ones. BH and KS are also are known as ''N'' (negative) and ''P'' (positive) perforations, respectively. The Bell & Howell perf remains the standard for camera negative films because of its perforation dimensions in comparison to most printers, thus having the ability to keep a steady image compared to other perforations.<ref name="gray">Gray, Peter. [http://www.jkor.com/peter/perfs.html "Sprocket Holes"]. Retrieved August 11, 2006.</ref>
'''DH perfs:''' The Dubray Howell (DH) perforation was first suggested in 1931 to replace both the BH and KS perfs with a single standard perforation which was a hybrid of the two in shape and size, being like KS a rectangle with rounded corners and a width of 0.1100" (2.79 mm), but with BH's height of 0.073" (1.85 mm).<ref name="achart" /> This gave it longer projection life but also improved registration. One of its primary applications was usage in [[Technicolor]]'s dye imbibition printing (dye transfer).<ref name="gray" /> The DH perf never caught on, and Kodak's introduction of monopack Eastmancolor film in the 1950s reduced the demand for dye transfer,<ref name="screensound" /> although the DH perf persists in certain special application intermediate films to this day.<ref name="dh">Eastman Kodak. [http://www.kodak.com/US/en/motion/products/intermediate/tech5242.jhtml?id=0.1.4.6.4.4.4&lc=en "Kodak Vision Color Intermediate Film - Technical Data"]. Retrieved August 11, 2006.</ref>
'''CS perfs:''' In 1953, the introduction of CinemaScope required the creation of a different shape of perforation which was nearly square and smaller to provide space for four magnetic sound stripes for stereophonic and surround sound.<ref name="hone" /> These perfs are commonly referred to as CinemaScope (CS) or "fox hole" perfs. Their dimensions are 0.073" (1.85 mm) in width by 0.078" (1.98 mm) in height.<ref name="case" /> Due to the size difference, CS perfed film cannot be run through a projector with standard KS sprocket teeth, but KS prints ''can'' be run on sprockets with CS teeth. Shrunken film with KS prints that would normally be damaged in a projector with KS sprockets may sometimes be run far more gently through a projector with CS sprockets because of the smaller size of the teeth. Though CS perfs have not been widely used since the late 1950s, Kodak still retains CS perfs as a special-order option on at least one type of print stock.<ref name="cs">Eastman Kodak. [http://www.kodak.com/US/en/motion/students/handbook/perforations1.jhtml?id=0.1.4.9.6&lc=en "Sizes and Shapes"]. Retrieved August 11, 2006.</ref>
During continuous contact printing, the raw stock and the negative are placed next to one another around the sprocket wheel of the printer. The negative, which is the closer of the two to the sprocket wheel (thus creating a slightly shorter path), must have a marginally shorter pitch between perforations (0.1866" pitch); the raw stock has a long pitch (0.1870"). While cellulose nitrate and cellulose diacetate stocks used to shrink during processing slightly enough to have this difference naturally occur, modern safety stocks do not shrink at the same rate, and therefore negative (and some intermediate) stocks are perforated at a pitch of 0.2% shorter than print stock.<ref name="case" />
===New innovations in sound===
[[Imagen:35mm film audio macro.jpg|200px|left|thumb|35mm film audio tracks, from left to right: [[SDDS]], [[Dolby Digital]], analog optical, and [[Digital Theater System|DTS]] time code.]]
New digital soundtracks introduced since the [[1990s]] include [[Dolby Digital]], which is stored in between the perforations on the sound side; [[SDDS]], stored in two [[redundancy (engineering)|redundant]] strips along the outside edges (beyond the perforations); and [[Digital Theatre System|DTS]], where sound data is stored on separate [[compact disc]]s synchronized by a [[timecode]] track stored on the film just to the right of the analog soundtrack and left of the frame.<ref name="filmtech">Norwood, Scott E. [http://www.film-tech.com/warehouse/tips/faq2/faq2.html Film-Tech FAQ]. Retrieved August 11, 2006.</ref> Because all these soundtrack systems appear on different parts of the film, one movie can contain all of them and be played in the widest possible number of [[theater]]s regardless of which sound systems are or are not installed. The optical track technology has changed too; currently all distributors and theaters are in the process of phasing over to cyan dye optical soundtracks instead of black and white (silver) tracks(which are less environmentally friendly). This requires replacing the incandescent exciter lamp with a red LED or laser, which is backwards-compatible with older tracks.<ref name="cyan">Hull, Joe. [http://www.dyetracks.org/FJI_Sept04.pdf "Committed to Cyan"]. Retrieved August 11, 2006.</ref> (The cyan tracks can't be read with older photo-sensors.) ''[[Anything Else]]'' (2003) was the first film only to be released with cyan tracks.<ref name="cyan" /> The transition is expected to be completed sometime around 2007 and has already happened in most multiplexes.
== Technical specifications ==
[[Imagen:35mmareas2.gif|thumb|450px|Areas on 35 mm film]]
Technical specifications for 35 mm film are standardized by [[Society of Motion Picture and Television Engineers|SMPTE]].
* 16 frames per foot (0.748" (19 mm) per frame (long pitch))
* 24 frames per second (fps); (90 feet per minute)
* vertical pulldown
* 4 perforations per frame (except if using 3-perf for origination)
1000 feet is about 11 minutes at 24 fps.
'''35 mm spherical'''<sup><ref name="asc" /></sup>
* 1.37:1 aspect ratio on camera negative; 1.85:1 and 1.66:1 are hard or soft matted over this
* ''camera aperture'': 0.866 by 0.630 in (22 by 16 mm)
* ''projector aperture'' (full 1.37:1): 0.825 by 0.602 in (21 by 15 mm)
* ''projector aperture'' (1.66:1): 0.825 by 0.497 in (21 by 13 mm)
* ''projector aperture'' (1.85:1): 0.825 by 0.446 in (21 by 11 mm)
* ''TV station aperture'': 0.816 by 0.612 in (21 by 16 mm)
* ''TV transmission'': 0.792 by 0.594 in (20 by 15 mm)
* ''TV safe action'': 0.713 by 0.535 in (18 by 14 mm); corner radii: 0.143 in (3.6 mm)
* ''TV safe titles'': 0.630 by 0.475 in (16 by 12 mm); corner radii: 0.125 in (3.2 mm)
'''Super 35 mm film'''<sup><ref name="asc" /></sup>
* 1.33:1 aspect ratio on camera negative
* ''camera aperture'': 0.980" by 0.735"
* ''picture used'' (35 mm anamorphic): 0.945" (24.00 mm) by 0.394" (10.00 mm)
* ''picture used'' (70 mm blowup): 0.945" (24.00 mm) by 0.430" (10.92 mm)
* ''picture used'' (35 mm flat 1.85): 0.945" (24.00 mm) by 0.511" (12.97 mm)
'''35 mm anamorphic'''<sup><ref name="asc" /></sup>
* 2.39:1 aspect ratio, from a 1.19:1 frame with a 2x horizontal squeeze
* ''camera aperture'': 0.866" (22.00 mm) by 0.732" (18.59 mm)
* ''projector aperture'': 0.825" (20.96 mm) by 0.690" (17.53 mm)
== See also ==
* [[16 mm film]]
* [[135 film|35 mm still photography film (135 film)]]
* [[70 mm film]]
* [[Color film (motion picture)]]
* [[Film base]]
* [[Filmstock]]
* [[History of film|History of the art and technique of making films]]
* [[Film|Motion picture]]
* [[Movie camera]]
* [[Movie projector]]
* [[Negative pulldown]]
* [[Original camera negative]]
* [[Photographic film]]
* [[Film formats|Still photography film formats]]
* [[Super 35 mm film]]
* [[Techniscope]]
===Lists===
* [[List of film formats]]
* [[List of motion picture film stocks]]
== Enlaces externos ==
* [http://www.widescreenmuseum.com/ American Widescreen Museum]
* [http://www.fujifilm.com/products/motion_picture/index.html Fujifilm Motion Picture Films]
* [http://www.kodak.com/US/en/motion/ Kodak: Cinematography]
* [http://www.cinetech.com/html/stocktimeline.html Motion Picture Stock Timeline]
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== Notas ==
<div class="references-small" style="-moz-column-count:2; column-count:2;"><references /></div>
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