Diferencia entre revisiones de «Película de 35 mm»

[[Archivo:Anamorphic-digital sound.jpg|right|thumb|250px|Fotogramas de una película de 35 mm.]]

[[Imagen:Film-frames-nba.jpg|thumb|right|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.

[[Imagen:VistaVision 8 perf 35 mm film.png|thumb|right|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&nbsp;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&nbsp;mm frame.<ref name="achart">Hart, Douglas C. ''The Camera Assistant: A Complete Professional Handbook''. Focal Press: Boston, 1996.</ref>

'''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.

'''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" />

[[Imagen:35mm_film_audio_macro35mm 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.]]