Film stock
Encyclopedia
- This focuses on motion picture film. For still photographyPhotographyPhotography is the art, science and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor or chemically by means of a light-sensitive material such as photographic film...
film, see photographic filmPhotographic filmPhotographic film is a sheet of plastic coated with an emulsion containing light-sensitive silver halide salts with variable crystal sizes that determine the sensitivity, contrast and resolution of the film...
.
Film stock is photographic film
Photographic film
Photographic film is a sheet of plastic coated with an emulsion containing light-sensitive silver halide salts with variable crystal sizes that determine the sensitivity, contrast and resolution of the film...
on which filmmaking
Filmmaking
Filmmaking is the process of making a film, from an initial story, idea, or commission, through scriptwriting, casting, shooting, directing, editing, and screening the finished product before an audience that may result in a theatrical release or television program...
of motion pictures are shot and reproduced. The equivalent in television production is video tape.
1889–1899
Early motion picture experiments were performed using paper roll film, which was difficult to view a single, continuously moving image without complex apparatus. The paper film was fragile. Transparent and flexible film baseFilm base
A film base is a transparent substrate which acts as a support medium for the photosensitive emulsion that lies atop it. Despite the numerous layers and coatings associated with the emulsion layer, the base generally accounts for the vast majority of the thickness of any given film stock...
material, celluloid
Celluloid
Celluloid is the name of a class of compounds created from nitrocellulose and camphor, plus dyes and other agents. Generally regarded to be the first thermoplastic, it was first created as Parkesine in 1862 and as Xylonite in 1869, before being registered as Celluloid in 1870. Celluloid is...
, was discovered and refined for photographic use by John Carbutt, Hannibal Goodwin
Hannibal Goodwin
Hannibal Goodwin , was an Episcopal priest at the House of Prayer in Newark, New Jersey, patented a method for making transparent, flexible roll film out of nitrocellulose film base, which was used in Thomas Edison's Kinetoscope, an early machine for viewing animation.-Biography:He was born in...
, and George Eastman
George Eastman
George Eastman was an American innovator and entrepreneur who founded the Eastman Kodak Company and invented roll film, helping to bring photography to the mainstream...
.
Eastman Kodak
Eastman Kodak
Eastman Kodak Company is a multinational imaging and photographic equipment, materials and services company headquarted in Rochester, New York, United States. It was founded by George Eastman in 1892....
made celluloid film commercially available in 1889; Thomas Henry Blair, in 1891, was its first competitor. The stock had a frosted base to facilitate easier viewing by transmitted light. Emulsions were orthochromatic
Orthochromatic
- Orthochromatic photography :Orthochromatic photography refers to a photographic emulsion that is sensitive to only blue and green light, and thus can be processed with a red safelight. The increased blue sensitivity causes blue objects to appear lighter and red ones darker...
. By November 1891 William Dickson
William Dickson (film pioneer)
William Kennedy Laurie Dickson was aFrench-born Anglo-Scots inventor who devised an early motion picture camera under the employment of Thomas Edison .-Biography:...
, at Edison's laboratory, was using Blair's stock for Kinetoscope
Kinetoscope
The Kinetoscope is an early motion picture exhibition device. Though not a movie projector—it was designed for films to be viewed individually through the window of a cabinet housing its components—the Kinetoscope introduced the basic approach that would become the standard for all cinematic...
experiments. Blair's company supplied film to Edison for five years. Between 1892 and 1893, Eastman experienced problems with production. Because of patent lawsuits in 1893, Blair left his American company and established another in Britain. Eastman supplied Edison with film.
Blair's new company supplied European filmmaking pioneers, including Birt Acres
Birt Acres
Birt Acres was a photographer and film pioneer.Born in Richmond, Virginia to English parents, he invented the first British 35 mm moving picture camera, the first daylight loading home movie camera and projector, Birtac, was the first travelling newsreel reporter in international film history and...
, Robert Paul
Robert Paul
Robert Paul was a Canadian figure skater, who competed in pairs with Barbara Wagner. He was born in Toronto. From their start as a team in 1952, they captured five Canadian titles and four world titles, and capped their career by winning the gold medal at the 1960 Winter Olympics.After skating as...
, George Albert Smith
George Albert Smith (inventor)
George Albert Smith was a stage hypnotist, psychic, magic lantern lecturer, astronomer, inventor, and one of the pioneers of British cinema, who is best known for his controversial work with Edmund Gurney at the Society for Psychical Research, his short-films from 1897-1903 which pioneered film...
, Charles Urban
Charles Urban
Charles Urban was an Anglo-American film producer and distributor, and one of the most significant figures in British cinema before the First World War...
, and the Lumiere Brothers. By 1896 the new movie projector
Movie projector
A movie projector is an opto-mechanical device for displaying moving pictures by projecting them on a projection screen. Most of the optical and mechanical elements, except for the illumination and sound devices, are present in movie cameras.-Physiology:...
required a fully transparent film base that Blair's American operation could not supply. Eastman shortly thereafter bought the company out and became the leading supplier of film stock. Louis Lumiere worked with Victor Planchon to adapt the Lumiere "Blue Label" (Etiquette Bleue) photographic plate emulsion for use on celluloid roll film, which began in early 1896.
Eastman's first motion picture film stock used the same emulsion as its still film, which was orthochromatic
Orthochromatic
- Orthochromatic photography :Orthochromatic photography refers to a photographic emulsion that is sensitive to only blue and green light, and thus can be processed with a red safelight. The increased blue sensitivity causes blue objects to appear lighter and red ones darker...
. Film did not have a strictly defined speed; the orthochromatic stock could be processed under a red safelight
Safelight
A safelight is a light source suitable for use in a photographic darkroom. It provides illumination only from parts of the visible spectrum to which the photographic material in use is nearly or completely insensitive.- Design :...
. Density was checked as development was occurring. Until the end of the silent era
Silent film
A silent film is a film with no synchronized recorded sound, especially with no spoken dialogue. In silent films for entertainment the dialogue is transmitted through muted gestures, pantomime and title cards...
, several inches were cut from the start of each shot developed to test it. Positive stock was slower, finer-grained and of a higher contrast than a negative.
From 1895, Eastman supplied their motion picture roll film in rolls of 65 feet, while Blair's rolls were 75 feet. If longer lengths were needed, the unexposed negative rolls could be cemented in a darkroom
Darkroom
A darkroom is a room that can be made completely dark to allow the processing of light sensitive photographic materials, including photographic film and photographic paper. Darkrooms have been created and used since the inception of photography in the early 19th century...
, but this was largely undesirable by most narrative filmmakers. Actuality film
Actuality film
The actuality film is a non-fiction film genre that like the documentary film uses footage of real events, places, and things, yet unlike the documentary is not structured into a larger argument, picture of the phenomenon or coherent whole. In practice, actuality films preceded the emergence of the...
s were much more eager to undertake this method, however, in order to depict longer actions, and created cemented rolls as long as 1000 feet. American Mutoscope and Biograph was the first known company to use this, for the Jeffries
James J. Jeffries
James Jackson Jeffries was a world heavyweight boxing champion.His greatest assets were his enormous strength and stamina. Using a technique taught to him by his trainer, former welterweight and middleweight champion Tommy Ryan, Jeffries fought out of a crouch with his left arm extended forward...
-Sharkey
Tom Sharkey
Tom 'Sailor Tom' Sharkey was a boxer who fought two fights with heavyweight champion James J. Jeffries. Sharkey's recorded ring career spanned from 1893 to 1904. He is credited with having won 40 fights , 7 losses, and 5 draws...
fight on November 3, 1899.
1900–1919
Film stocks improved slowly between 1900 and 1910, as the equipment and formats gradually became standardized. many differing film gaugeFilm gauge
Film gauge is a physical property of photographic or motion picture film stock which defines its width. Traditionally the major film gauges in usage are 8 mm, 16 mm, 35 mm, and 65/70 mm...
s were made. Eastman retained a large market share without major adjustments to the emulsion, increasing the length of rolls to 200 feet. Lumiere reformulated its stock to match the speed of Eastman film, naming it 'Etiquette Violette' (Violet Label). Blair sold his English company to Pathé
Pathé
Pathé or Pathé Frères is the name of various French businesses founded and originally run by the Pathé Brothers of France.-History:...
in 1907 and retired to the US. Pathe began to supplement its operation in 1910 by purchasing film prints, strip the emulsion from the film base and re-coating it.
As the quantity of film and filmmakers grew, the demand for standardization increased. Because of the popularity of Edison's and Lumière's cameras, 35mm film began to become the dominant gauge. this was usually purchased unperforated and punched by the consumer with perforation equipment. Perforators were often imprecise, causing difficulty in making prints for the opposite perforation format. Edison's organization of the Motion Picture Patents Trust agreed in 1909 to what would become the standard: 35 mm gauge, with Edison perforations and a 1.33 aspect ratio
Aspect ratio (image)
The aspect ratio of an image is the ratio of the width of the image to its height, expressed as two numbers separated by a colon. That is, for an x:y aspect ratio, no matter how big or small the image is, if the width is divided into x units of equal length and the height is measured using this...
?
Bell and Howell began making perforators in 1908. Eastman Kodak used Bell and Howell's machine to perforate its films.
Agfa began to produce motion picture film in 1913, but remained a largely local supplier until World War I boycotts of popular French, American and Italian film stocks allowed the UFA
Universum Film AG
Universum Film AG, better known as UFA or Ufa, is a film company that was the principal film studio in Germany, home of the German film industry during the Weimar Republic and through World War II, and a major force in world cinema from 1917 to 1945...
film studio to flourish, boosting Agfa's orders.
Nitrocellulose
Nitrocellulose is a highly flammable compound formed by nitrating cellulose through exposure to nitric acid or another powerful nitrating agent. When used as a propellant or low-order explosive, it is also known as guncotton...
film base
Film base
A film base is a transparent substrate which acts as a support medium for the photosensitive emulsion that lies atop it. Despite the numerous layers and coatings associated with the emulsion layer, the base generally accounts for the vast majority of the thickness of any given film stock...
, which is highly flammable. Nitrate film fires were difficult to extinguish. A significant number of fatal accidents occurred in theatrical projection booths, where the heat of the projector lamp made ignition most likely.
Amateur filmmaking
Filmmaking
Filmmaking is the process of making a film, from an initial story, idea, or commission, through scriptwriting, casting, shooting, directing, editing, and screening the finished product before an audience that may result in a theatrical release or television program...
(home movies
Home movies
A home movie is part of the motion picture filmmaking process made by amateurs, often for viewing by family and friends. When the hobby began, home movies were produced on photographic film, but accessibility of video production with video cameras and low cost data storage devices has made the...
) slowly developed during this period. Kodak developed a heat-resistant 'safety base' for home projection. In 1909, tests showed cellulose diacetate to be a viable replacement base, and Kodak began selling acetate-base films the following year in 22 mm widths for Edison's work on the Home Kinetoscope, which was commercially released in 1912. Eastman Kodak introduced a non-inflammable 35 mm film stock in 1909. The plasticizer
Plasticizer
Plasticizers or dispersants are additives that increase the plasticity or fluidity of the material to which they are added; these include plastics, cement, concrete, wallboard, and clay. Although the same compounds are often used for both plastics and concretes the desired effects and results are...
s used to make the film flexible evaporated quickly, making the film dry and brittle, causing splices to part and perforations to tear. In 1911 the major American film studios returned to using nitrate stock. More amateur formats began to use acetate based film, and several, including Kodak's own 16 mm format, were designed specifically to be manufactured with safety base.
Kodak released Cine Negative Film Type E in 1916 and Type F (later known as Negative Film Par Speed Type 1201) in 1917. As both of these orthochromatic films were no faster than previous offerings; the improvements were in granularity and sharpness.
1920s
Film stock manufacturers began to diversify their products. Each manufacturer had previously offered one negative stock (usually orthochromatic) and one print stock. In 1920, a variant of Type F film known as X-back was introduced to counteract the effects of static electricity on the film, which can cause sparking and create odd exposure patterns on the film. A resin backing was used on the film, which rendered the film too opaque to allow focusing through the back of the film, a common technique for many cameras of that era. The X-back stock was popular on the east coast of the US. Other manufacturers were established in the 1920s, including American E.I. Dupont de Nemours in 1926 and Belgian GevaertAgfa-Gevaert
Agfa-Gevaert N.V. is a European multinational corporation that develops, manufactures, and distributes analogue and digital imaging products and systems, as well as IT solutions. The company has three divisions. Agfa Graphics offers integrated prepress and industrial inkjet systems to the...
in 1925.
Panchromatic
Panchromatic
Panchromatic film is a type of black-and-white photographic film that is sensitive to all wavelengths of visible light. A panchromatic film therefore produces a realistic reproduction of a scene as it appears to the human eye. Almost all modern photographic film is panchromatic, but some types are...
film stock became more common. Created in 1913 for use in color film processes such as Kinemacolor
Kinemacolor
Kinemacolor was the first successful color motion picture process, used commercially from 1908 to 1914. It was invented by George Albert Smith of Brighton, England in 1906. He was influenced by the work of William Norman Lascelles Davidson. It was launched by Charles Urban's Urban Trading Co. of...
, panchromatic was first used in a black-and-white film for exterior sequences in Queen of the Sea (1918) and originally available as a special order product. The stock's increased sensitivity to red light made it an attractive option for day for night
Day for night
Day for night, also known as nuit américaine , is the name for cinematographic techniques used to simulate a night scene; such as using tungsten-balanced rather than daylight-balanced film stock or with special blue filters and also under-exposing the shot to create the illusion of darkness or...
shooting. Kodak financed a feature in 1922 shot entirely with panchromatic stock, The Headless Horseman, to promote the film when Kodak introduced it as a standard option. Panchromatic film stock was expensive and no motion pictures were produced in entirety on it for several years. The cross-cutting between panchromatic and orthochromatic stocks caused continuity problems with costume tones and panchromatic film was often avoided. Orthochromatic film remained dominant until the mid 1920s due to Kodak's lack of competition in the panchromatic market. In 1925, Gevaert introduced an orthochromatic stock with limited color sensitivity and a fully panchromatic stock, Pan-23. In 1926, Kodak lowered the price of panchromatic stock to parity with its orthochromatic offering and the panchromatic stock began to overtake the orthochromatic stock's market share within a few years. Similar panchromatic film stocks were manufactured by Agfa and Pathé, the shift to panchromatic stocks had largely been completed by 1928, and Kodak discontinued orthochromatic stock in 1930.
Color films
Experiments with color films were made as early as the late 19th century, but practical color film was not commercially viable until 1908, and for amateur use when Kodak introduced KodachromeKodachrome
Kodachrome is the trademarked brand name of a type of color reversal film that was manufactured by Eastman Kodak from 1935 to 2009.-Background:...
for 16 mm in 1935 and 8 mm
8 mm film
8 mm film is a motion picture film format in which the filmstrip is eight millimeters wide. It exists in two main versions: the original standard 8mm film, also known as regular 8 mm or Double 8 mm, and Super 8...
in 1936.
Before 1941, commercially successful color processes used special cameras loaded with black-and-white separation stocks rather than color negative. Kinemacolor
Kinemacolor
Kinemacolor was the first successful color motion picture process, used commercially from 1908 to 1914. It was invented by George Albert Smith of Brighton, England in 1906. He was influenced by the work of William Norman Lascelles Davidson. It was launched by Charles Urban's Urban Trading Co. of...
(1908–1914), Technicolor
Technicolor
Technicolor is a color motion picture process invented in 1916 and improved over several decades.It was the second major process, after Britain's Kinemacolor, and the most widely used color process in Hollywood from 1922 to 1952...
processes 1 through 4 (1917–1954), and Cinecolor
Cinecolor
Cinecolor was an early subtractive color-model two color film process, based upon the Prizma system of the 1910s and 1920s and the Multicolor system of the late 1920s and 1930s. It was developed by William T. Crispinel and Alan M...
used one, two or three strips of monochrome film stock sensitized to certain primary colors or exposed behind color filters in special cameras.
Technicolor introduced a color reversal stock, called Monopack, for location shooting in 1941; it was ultimately a 35 mm version of Kodachrome that could be used in standard motion picture cameras. Eastman Kodak introduced their first 35mm
35 mm film
35 mm film is the film gauge most commonly used for chemical still photography and motion pictures. The name of the gauge refers to the width of the photographic film, which consists of strips 35 millimeters in width...
color negative stock, Eastman Color Negative film 5247, in 1950. A higher quality version in 1952, Eastman Color Negative film 5248, was quickly adopted by Hollywood for color motion picture production, replacing both the expensive three-strip Technicolor process and Monopack.
Classification and properties
Base
A piece of film consists of a light-sensitive emulsionEmulsion
An emulsion is a mixture of two or more liquids that are normally immiscible . Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion is used when both the dispersed and the...
applied to a tough, transparent base
Film base
A film base is a transparent substrate which acts as a support medium for the photosensitive emulsion that lies atop it. Despite the numerous layers and coatings associated with the emulsion layer, the base generally accounts for the vast majority of the thickness of any given film stock...
, sometimes attached to anti-halation backing
Anti-halation backing
An anti-halation backing is a layer found in most photographic films. It is usually a coating on the back of the film base, but sometimes it is incorporated between the light-sensitive emulsion and the base. The light that passes through the emulsion is absorbed by the anti-halation layer...
or "rem-jet" layer (now only on camera films). Originally the highly flammable cellulose nitrate
Nitrocellulose
Nitrocellulose is a highly flammable compound formed by nitrating cellulose through exposure to nitric acid or another powerful nitrating agent. When used as a propellant or low-order explosive, it is also known as guncotton...
was used. In the 1930s, film manufacturers introduced "safety film" with a cellulose triacetate plastic base***. All amateur film stocks were safety film, but the use of nitrate persisted for professional releases. Kodak discontinued the manufacture of nitrate base in 1951, and the industry transitioned entirely to safety film in 1951 in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and by 1955 internationally. Since the late 1990s, almost all release prints have used polyester
Polyester
Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...
film stock.
Emulsion
The emulsion consists of silver halideSilver halide
A silver halide is one of the compounds formed between silver and one of the halogens — silver bromide , chloride , iodide , and three forms of silver fluorides. As a group, they are often referred to as the silver halides, and are often given the pseudo-chemical notation AgX...
grains suspended in a gelatin
Gelatin
Gelatin is a translucent, colorless, brittle , flavorless solid substance, derived from the collagen inside animals' skin and bones. It is commonly used as a gelling agent in food, pharmaceuticals, photography, and cosmetic manufacturing. Substances containing gelatin or functioning in a similar...
colloid; in the case of color film, there are three layers of silver halide, which are mixed with color couplers and interlayers that filter specific light spectra. These end up creating yellow, cyan
Cyan
Cyan from , transliterated: kýanos, meaning "dark blue substance") may be used as the name of any of a number of colors in the blue/green range of the spectrum. In reference to the visible spectrum cyan is used to refer to the color obtained by mixing equal amounts of green and blue light or the...
, and magenta
Magenta
Magenta is a color evoked by light stronger in blue and red wavelengths than in yellowish-green wavelengths . In light experiments, magenta can be produced by removing the lime-green wavelengths from white light...
layers in the negative after development.
Chemistry
Development chemicals applied to an appropriate film can produce either a positive (showing the same densities and colors as the subject) or negative image (with dark highlights, light shadows, and, in principle, complementary colors). The first films were darkened by light: negative films. Later films that produce a positive image became known as reversal films; processed transparent film of this type can be projectedMovie projector
A movie projector is an opto-mechanical device for displaying moving pictures by projecting them on a projection screen. Most of the optical and mechanical elements, except for the illumination and sound devices, are present in movie cameras.-Physiology:...
onto a screen. Negative images need to be transferred onto photographic paper or other substrate which reverses the image again, producing a final positive image. Creating a positive image from a negative film can also be done by scanning
Image scanner
In computing, an image scanner—often abbreviated to just scanner—is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Common examples found in offices are variations of the desktop scanner where the document is placed on a glass...
the negative to create a computer file which can then be reversed by software.
Image record
Different emulsions and development processes exist for a variety of image recording possibilities: the two most common of which are black and white, and color. However, there are also variant types, such as infrared film (in black and white or false color); specialist technical films, such as those used for X-rays; and obsolete processes, such as orthochromaticOrthochromatic
- Orthochromatic photography :Orthochromatic photography refers to a photographic emulsion that is sensitive to only blue and green light, and thus can be processed with a red safelight. The increased blue sensitivity causes blue objects to appear lighter and red ones darker...
film. Generally, however, the vast majority of stock used today is "normal" (visible spectrum) color, although "normal" black and white also commands a significant minority percentage.
Physical characteristics
Film is also classified according to its gaugeFilm gauge
Film gauge is a physical property of photographic or motion picture film stock which defines its width. Traditionally the major film gauges in usage are 8 mm, 16 mm, 35 mm, and 65/70 mm...
and the arrangement of its perforations
Film perforations
Film perforations, also known as perfs, are the holes placed in the film stock during manufacturing and used for transporting and steadying the film. Films may have different types of perforations depending on film gauge, film format, and the intended usage...
— gauges range from 8 mm
8 mm film
8 mm film is a motion picture film format in which the filmstrip is eight millimeters wide. It exists in two main versions: the original standard 8mm film, also known as regular 8 mm or Double 8 mm, and Super 8...
to 70 mm
70 mm film
70mm film is a wide high-resolution film gauge, with higher resolution than standard 35mm motion picture film format. As used in camera, the film is wide. For projection, the original 65mm film is printed on film. The additional 5mm are for magnetic strips holding four of the six tracks of sound...
or more, while perforations may vary in shape, pitch, and positioning. The film is also distinguished by how it is wound with regard to perforations and base or emulsion side, as well as whether it is packaged around a core, a daylight spool, or within a cartridge. Depending on the manufacturing processes and camera equipment, lengths can vary anywhere from 25 to 2000 feet. Common lengths include 25 feet for 8 mm, 50 feet for Super 8
Super 8 mm film
Super 8 mm film is a motion picture film format released in 1965 by Eastman Kodak as an improvement of the older "Double" or "Regular" 8 mm home movie format....
, 100 and 400 feet for 16 mm, 400 and 1000 feet for 35 mm, and 1000 for 65/70 mm.
Responsivity
A critical property of a stock is its film speedFilm speed
Film speed is the measure of a photographic film's sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system....
, determined by ASA or its sensitivity to light listed by a measurement on the raw stock which must be chosen with care. Speed determines the range of lighting conditions under which the film can be shot, and is related to granularity
Film grain
Film grain or granularity is the random optical texture of processed photographic film due to the presence of small particles of a metallic silver, or dye clouds, developed from silver halide that have received enough photons. While film grain is a function of such particles it is not the same...
and contrast, which influence the look of the image. The stock manufacturer will usually give an exposure index (EI) number equal to the ASA which they recommend exposing for. However, factors such as forced or non-standard development (such as bleach bypass
Bleach bypass
Bleach bypass, also known as skip bleach or silver retention, is an optical effect which entails either the partial or complete skipping of the bleaching function during the processing of a color film. By doing this, the silver is retained in the emulsion along with the color dyes. The result is a...
or cross processing
Cross processing
Cross processing is the procedure of deliberately processing photographic film in a chemical solution intended for a different type of film. The effect was discovered independently by many different photographers often by mistake in the days of C-22 and E-4...
), compensation for filters or shutter angle, as well as intended under- and over-exposure may cause the cinematographer to actually "rate" the stock differently from the EI. This new rating is not a change to the stock itself - it is merely a way of calculating exposure without figuring out the compensation after each light reading.
Color temperature
Another important quality of color film stock in particular is its color balanceColor balance
In photography and image processing, color balance is the global adjustment of the intensities of the colors . An important goal of this adjustment is to render specific colors – particularly neutral colors – correctly; hence, the general method is sometimes called gray balance, neutral balance,...
, which is defined by the color temperature
Color temperature
Color temperature is a characteristic of visible light that has important applications in lighting, photography, videography, publishing, manufacturing, astrophysics, and other fields. The color temperature of a light source is the temperature of an ideal black-body radiator that radiates light of...
at which it accurately records white. Tungsten
Tungsten
Tungsten , also known as wolfram , is a chemical element with the chemical symbol W and atomic number 74.A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as...
lighting is defined at 3200 K, which is considered "warmer" in tone and shifted towards orange; daylight
Daylight
Daylight or the light of day is the combination of all direct and indirect sunlight outdoors during the daytime. This includes direct sunlight, diffuse sky radiation, and both of these reflected from the Earth and terrestrial objects. Sunlight scattered or reflected from objects in outer space is...
is defined at 5600 K, which is considered "colder" and shifted towards blue. This means that unfiltered tungsten stock will look normal shot under tungsten lights, but blue if shot during daylight. Conversely, daylight stock shot in daylight will look normal, but orange if shot under tungsten lights. Color temperature issues such as these can be compensated for by other factors such as lens filters and color gels placed in front of the lights. The color temperature of a film stock is generally indicated next to the film speed number - e.g. 500T stock is color film stock with an ASA of 500 and balanced for tungsten light; 250D would have an ASA of 250 and be balanced for daylight.
While black-and-white film has no color temperature itself, the silver halide grains themselves tend to be slightly more responsive to blue light, and therefore will have daylight and tungsten speeds - e.g. Kodak's Double-X stock is rated 250D/200T, since the tungsten light will give slightly less exposure than an equivalent amount of daylight.
Deterioration
All plastic is subject to deteriorationPolymer degradation
Polymer degradation is a change in the properties—tensile strength, colour, shape, etc.—of a polymer or polymer-based product under the influence of one or more environmental factors such as heat, light or chemicals such as acids, alkalis and some salts...
through physical or chemical means, and thus, motion picture film is subject to the same deterioration. Cellulose nitrate, cellulose diacetate and triacetate are known to be unstable mediums: improperly preserved film can deteriorate in a period of time much faster than many photographs or other visual presentations.
Cellulose nitrate, because of its unstable chemistry, eventually breaks down, releasing nitric acid, further catalyzing the decomposition. In the final stages of celluloid decomposition, the film turns into a rust-like powder.
Likewise, tri-acetate stock is also vulnerable to deterioration. Because of the small gauge of the film, owners of home-made films often find that their film can become shrunken and brittle to the point where the film is unwatchable in the space of a few years. In general, decaying acetate film breaks down into acetic acid
Acetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...
, and similar to celluloid decomposition, leads to an auto-catylictic breakdown of the base that cannot be reversed. The result of the acetic acid released is a strong odor of vinegar
Vinegar
Vinegar is a liquid substance consisting mainly of acetic acid and water, the acetic acid being produced through the fermentation of ethanol by acetic acid bacteria. Commercial vinegar is produced either by fast or slow fermentation processes. Slow methods generally are used with traditional...
, which is why the decay process in the archival community is known as "vinegar syndrome".
Modern polyester-based stocks are far more stable by comparison and are rated to last hundreds of years.
Intermediate and print stocks
Digital intermediate
Digital intermediate is a motion picture finishing process which classically involves digitizing a motion picture and manipulating the color and other image characteristics. It often replaces or augments the photochemical timing process and is usually the final creative adjustment to a movie...
(DI), it has become possible to completely edit, composite visual effects, and color grade the image digitally at full resolution and bit-depth. In this workflow, the answer print is generated digitally and then written out to the IP stage using a laser film printer.
Due to the specialized nature of the exposure and the higher degree of control afforded by the film lab equipment, these intermediate and release stocks are specially designed solely for these applications and are generally not feasible for camera shooting. Because intermediates only function to maintain the image information accurately across duplication, each manufacturer tends to only produce one or two different intermediate stocks. Similarly, release print stocks usually are available only in two varieties: a "normal" print or a deluxe print (on more-costly print film like Kodak Vision Premiere) with slightly greater saturation and contrast.
See also
- Direct film
- Film formatFilm formatA film format is a technical definition of a set of standard characteristics regarding image capture on photographic film, for either stills or movies. It can also apply to projected film, either slides or movies. The primary characteristic of a film format is its size and shape.In the case of...
- Film preservationFilm preservationthumb|300px|Stacked containers filled with reels of [[film stock]]The film preservation, or film restoration, movement is an ongoing project among film historians, archivists, museums, cinematheques, and non-profit organizations to rescue decaying film stock and preserve the images which they contain...
- List of film formats
- List of motion picture film stocks
- Color motion picture film
- Photographic filmPhotographic filmPhotographic film is a sheet of plastic coated with an emulsion containing light-sensitive silver halide salts with variable crystal sizes that determine the sensitivity, contrast and resolution of the film...
with emphasis on film for still photography.