Le '''format ''' est le nom d’un type de millimètres de largeur. Créé à l’origine pour le format dominant.

== Utilisation au cinéma ==
367px|thumb|none|Description d’un film  ;  suppose un projecteur à chargement à droite (en regardant la salle), ce qui est le cas général
Dans le cas de l’usage cinématographique, les images utilisent la plus grande largeur de la pellicule, mais une portion est utilisée pour inscrire le son à côté de l’image. Un masque permet d’éviter que cette bande blanche de largeur variable ne soit visible sur l’écran pendant la projection.

La pellicule présente quatre perforations par image, de chaque côté de la pellicule.

Le rapport d’image (ratio) est de 1,33:1 jusqu’aux années 1930 : toute la zone réservée à l’image est exposée. Avec l’arrivée du cinéma sonore et la nécessité de loger une piste sonore, le ratio est ramené à 1,375:1 (communément appelé 1,37:1). 
La pellicule  est aussi fréquemment utilisée au lieu du  pour la production d’images au format prise de vue et la projection se font avec des objectifs anamorphiques qui compressent l’image dans un format hybride de 1,195:1. Il est également courant de masquer à la prise de vue une partie de l’image en hauteur pour obtenir des formats plus rectangulaires dont les plus courants sont le 1,85:1 et le 1,66:1.

== Utilisation en photographie ==
Le format  (''pellicule 135'') est le support le plus courant en moyen et grand formats).

Les formats de prises de vue sur une pellicule 135 sont nombreux, le principal étant le }} (défilement horizontal de la pellicule). D’anciens modèles reprenaient le fonctionnement d’une photos de }} : on parlait de demi-format. Aujourd’hui, on note aussi de nombreux formats panoramiques - les dimensions ne sont pas standardisées, mais on peut citer le }}.

right|thumb|250px|35&nbsp;mm film print frames. At far left and far right, outside the perforations, is the [[Sony Dynamic Digital Sound|SDDS soundtrack as an image of a digital signal. Between the perforations is the Dolby SR noise reduction that can be dematrixed into four channels using DTS soundtrack, which sits between the optical soundtrack and the image, is not pictured. Finally, the image here is an anamorphic image used to create a 2.39:1 aspect ratio when projected through an anamorphic lens. Note the thin frame lines of anamorphic prints.]]

'''35 mm film''' is the basic William Dickson and SMPTE, or 34.975 mm. The size was created by Dickson in collaboration with Eastman, and would have been in standard, not metric, units. An account of this is given in an article by Dickson in a 1933 SMPTE Journal. [http://www.subclub.org/shop/halframe.htm "Half Frame Cameras"]. Retrieved August 12, 2006. This size is also exactly half the width of the 2 3/4 inch-wide (69.85 mm) "A-type" rollfilm which was the standard Eastman size at the time. [http://www.eastman.org/fm/mees/htmlsrc/mE12900002_ful.html "Enhancing the Illusion: The Process and Origins of Photography"], George Eastman House. Retrieved August 12, 2006.</ref><ref name="smpte139">ANSI/SMPTE 139–1996. ''SMPTE STANDARD for Motion-Picture Film (35mm) - Perforated KS.'' Society of Motion Picture and Television Engineers. White Plains, NY.</ref> The standard perforations per frame along both edges, which makes for exactly 16 frames per foot<ref name="acm">Hummel, Rob (ed). ''American Cinematographer Manual'', 8th edition. ASC Press: Hollywood, 2001.</ref> (for stills, the standard frame is eight perforations). 

A wide variety of largely proprietary gauges were used by the numerous camera and projection systems  invented independently in the late 19th century and early 20th century, ranging from 13&nbsp;mm to 75&nbsp;mm (0.51&ndash;2.95&nbsp;in).<ref name="gauges">Horak, Jan-Christopher. UCLA Film and Television Archive, [http://www.cinema.ucla.edu/tank/GaugesHorak.htm "Introduction to Film Gauges"]. Retrieved August 11, 2006.</ref> 35&nbsp;mm was eventually recognized as the international standard gauge in 1909,<ref name="alsobrook">Alsobrook, Russ T. International Cinematographers Guild, [http://www.cameraguild.com/interviews/chat_alsobrook/alsobrook_machines1.htm "Machines That Made the Movies, Part 1"]. Retrieved August 11, 2006.</ref> and has remained by far the dominant film gauge for image origination and projection despite threats from smaller and larger gauges, and from novel formats, because its size allows for a relatively good tradeoff between the cost of the film stock and the quality of the images captured. The ubiquity of 35&nbsp;mm movie projectors in commercial movie theaters makes it the only motion picture format, film or video, that can be played in almost any cinema in the world. 

The gauge is remarkably versatile in application. In the past one hundred years, it has been modified to include sound, redesigned to create a safer film base, formulated to capture color, has accommodated a bevy of widescreen formats, and has incorporated digital sound data into nearly all of its non-frame areas. Since the beginning of the 21st century, Eastman Kodak and Fujifilm have held a duopoly in the manufacture of 35&nbsp;mm motion picture film.

== Early history ==

In 1880, Rochester, perforated film stock. Eastman was the first major company, however, to mass-produce these components, when in 1889 Eastman realized that the dry-gelatino-bromide emulsion could be coated onto this clear base, eliminating the paper.<ref>Mees, C. E. Kenneth (1961). ''From Dry Plates to Ektachrome Film: A Story of Photographic Research''. Ziff-Davis Publishing. pp. 15–16.</ref>

With the advent of flexible film, Kinetophone, which combined the Kinetoscope with Edison's cylinder American Mutoscope & Biograph, to use a 68&nbsp;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&nbsp;mm film design without license. Filmmakers were already doing so in Britain and Europe, where Edison had failed to file patents.<ref></ref> A variation developed by the 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 trust established by Edison. Scholar Paul C. Spehr describes the importance of these developments:

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 28&nbsp;mm (1.1&nbsp;in) (1912), 9.5 mm (0.37&nbsp;in) (1922), 16 mm (0.63&nbsp;in) (1923), and Pathe Rural, a 17.5&nbsp;mm format designed for safety film (1926). Eastman Kodak's 16&nbsp;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&nbsp;mm size was specifically chosen to prevent third-party slitting, as it was very easy to create 17.5&nbsp;mm stock from slitting 35&nbsp;mm stock in two. It also was the first major format only to 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 (0.31&nbsp;in) 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&nbsp;mm gauge almost the exclusive province of professional filmmakers, a divide which mostly remains to this day.

== How film works ==
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Inside the photographic emulsion are millions of light-sensitive 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>

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; antihalation 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-sensitive 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 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 problem of higher speed (greater light sensitivity — see 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 infrared.

== Attributes ==
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=== Color ===

Originally, film was a strip of cellulose nitrate coated with black-and-white photographic tinted or toned portions of their movies for dramatic impact, and by 1920, 80 to 90 percent of all films were tinted.<ref></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></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 35 mm film called 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 two-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 advantage 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&nbsp;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 nitrate-based films with the safer, more robust 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 in the early 1990s). Ironically, 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:  2–3&nbsp;ft or ~2 sec. Also, polyester film will melt if exposed to the projector lamp 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 ====

In the conventional motion picture format, frames are four perforations tall, with an Fox placed the soundtrack in an optical record directly on the film (sound-on-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, resulting in an almost square image ratio. 

In 1932, to restore a more rectangular image ratio, the picture was shrunk slightly vertically, with the line between frames thickened. Hence the frame became 22&nbsp;mm by 16&nbsp;mm (0.866&nbsp;in by 0.630&nbsp;in) with an aspect ratio of 1.37:1. This became known as the "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> 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&nbsp;mm by 16&nbsp;mm (0.816&nbsp;in by 0.612&nbsp;in), 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 ====

The commonly used anamorphic 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>

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 in order to compete with the growing audiences of television and the dwindling audiences in movie theaters. These processes could give theatergoers an experience that television couldn't-- color, stereophonic sound and panoramic vision.  Before the end of the year, 20th Century Fox had narrowly "won" a race to obtain an anamorphic optical system invented by Henri Chrétien, and soon began promoting 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>

Looking for a similar alternative, other major studios hit upon a simpler, less expensive solution by May 1953: using a removable aperture plate in the film projector gate, the top and bottom of the frame could be cropped to create a wider aspect ratio. Paramount Studios began this trend with their aspect ratio of 1.66:1, first used in ''Shane'', which was originally shot for Thunder Bay'' that introduced the now standard 1.85:1 format to American audiences and brought attention to the industry the capability and low cost of equipping theaters for this transition.

Other studios followed suit with aspect ratios of 1.75:1 up to 2:1. For a time, these various ratios were used by different studios in different productions, but by 1956, the aspect ratio of 1.85:1 became the "standard" US format. These ''flat'' films are photographed with the full 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, although some productions with pre-determined American distributors compose for the latter in order to appeal to US markets.