Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Film Stock shopping experience:

1. Compare - without doubt the biggest advantage that the Film Stock offers shoppers today is the ability to compare thousands of Film Stock at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.

2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about

3. Testimonials - don't know anybody that has bought a Film Stock? Wrong! If the Film Stock is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.

4. Questions - Got a question about Film Stock then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....

5. Reputation - Never heard of the company selling Film Stock? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Film Stock and build up a picture of their reputation for sales, returns, customer service, delivery etc.

6. Returns - still worried that even after all of the above your Film Stock wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.

7. Feedback - happy with your Film Stock then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.

8. Security - check for the yellow padlock on the Film Stock site before you buy, and the s after http:/ /i.e. https:// = a secure site

9. Contact - got a question about Film Stock, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.

10. Payment - ready to pay for your Film Stock, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.

This article is mainly concerned with motion picture film. For still photography film, please see photographic film. Film stock is the term for photographic film on which Film are shot and reproduced.

History 1889-1899 Modern motion picture film stock was first created thanks to the introduction of a transparent flexible film base material, celluloid, which was discovered and refined for photographic use thanks to the work of John Carbutt, Hannibal Goodwin, and George Eastman. Prior to this, most motion picture experiments were performed using paper roll film, which made it difficult if not impossible to view the developed film as a single continuous moving image without other complex apparatuses. Furthermore, the paper film was much more fragile than celluloid.

Eastman Kodak would become the first to make celluloid film commercially available, starting in 1889; Thomas Henry Blair emerged in 1891 as the first major competitor for supplying celluloid film. The stock had a frosted base in order to facilitate easier viewing by transmitted back light, and the emulsions from each company were orthochromatic. By November 1891 William Dickson (film pioneer) at Edison's lab was using Blair's stock for Kinetoscope tests, and Blair's company remained a main supplier of film to the Edison lab for the next five years. Blair's operation was also crucial to the continued development of motion picture technology through 1892 and 1893, due to temporary shutdowns at Eastman because of problems with their production setup. Eventually patent lawsuits in 1893 led to Blair leaving his American company and starting again in England, which allowed Eastman to gradually fill the entirety of the Edison lab's film orders. Blair's new headquarters allowed him to supply many of the key European filmmaking pioneers, including Birt Acres, Robert Paul, George Albert Smith, Charles Urban, and the Lumiere Brothers. The American Blair company was to be shortlived, however, as by 1896 the new movie projector would demand a fully transparent film base that they had difficulty supplying. Eastman shortly thereafter bought the company out, thus consolidating its position as the leading supplier of film stock from then on. These developments also led Louis Lumiere to work with Victor Planchon on adapting the Lumiere "Blue Label" (Etiquette Bleue) photographic plate emulsion for use on celluloid roll film, which began in early 1896 and was brought to full production capacity by the following year.

Eastman's first motion picture film stock incorporated the same emulsion as was used for its still film, which was, like nearly all film emulsion of the time, orthochromatic-sensitive. Film at this point did not have a strictly defined speed; rather, the orthochromatic quality of the stock allowed the film to be processed under a red safelight, while the density was checked as development was occurring. Standard practice until the end of the silent film involved tearing off several inches from the start of each shot and testing development on it. Positive stock was created which would be slower, finer-grained, and of a higher contrast than a negative; all of these characteristics remain consistent to this day.

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, but this was largely undesirable by most narrative filmmakers. Actuality films 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 James J. Jeffries-Tom Sharkey fight on November 3, 1899.

1900-1919 Work on improved film stocks was rather slow in the first decade of the new century, as the equipment and list of film formats, particularly, were still in the process of gradually standardizing. With a large number of differing film gauges in use, supplying a market still in its infancy was likely a difficult task, and Eastman was able to retain the majority of the market share without making major adjustments to the emulsion; their only major change was to increase the length of rolls to 200 feet. Lumiere, on the other hand, reformulated their stock to match the speed of Eastman film, which became known as "Violet Label" (Etiquette Violette). Blair retired back to the United States after selling his English company to Pathe in 1907, who began using the facilities for producing their own film stock. This sale had future repercussions among film preservation, as Pathe began to supplement their operation in 1910 by purchasing film prints in order to strip the silver and emulsion from the film base for recoating.

As the quantity of film and filmmakers grew in these early years, the demand for standardization increased in prominence. 35 mm film, largely thanks to the popularity of the Edison and Lumiere camera lines (and their often unauthorized clones) had begun to stabilize as the dominant gauge, but still was usually purchased unperforated, and subsequently punched by the consumer with perforation equipment designed by third parties. Although Edison (4 square perfs per frame on each side) and Lumiere (1 rounded perf per frame on each side) formats - based on the camera designs - were the most common, the perforators were not always precise, and it could be difficult to create prints for the opposite perforation format. Edison's organization of the Edison Trust, though largely ineffective in controlling the burgeoning film industry, was able in 1909 to agree to what would become the de facto standard: 35 mm gauge, with Edison perforations and a 1.33 aspect ratio (image). These parameters have remained largely constant to the present day.The gauge and perforations are more or less identical to modern film stock; the full silent ratio is also generally still used as the film gate in movie cameras, although portions of the image are later cropped out in post-production and projection.

The Bell and Howell company perforators entered the market in 1908 and very shortly were recognized as exceptional enough to pervade the American industry. Eastman Kodak was also quick to opt to use the machine to pre-perforate their films, which assured the perforation specifications being adopted as the world standard not long after. These perforations, known as BH-type, remain the standard for original camera negative film.

The belle epoque era also saw the creation of numerous small, local film suppliers, the vast majority of which were short-lived due to their smaller production batches, slower emulsions (which were also usually blue-only sensitive rather than orthochromatic), and inferior quality control. Among these companies, Agfa began to produce motion picture film in 1913, but remained a largely local supplier until post-World War I boycotts of popular French films allowed the newly-founded Universum Film AG film studio to flourish and thus boosted Agfa's orders.

Among the foremost problems with the film stocks of this era was that they were all manufactured on a nitrocellulose film base, which was a derivate of guncotton and thus highly flammable. Additionally, nitrate fires were notoriously difficult to put out, as even full submersion in water will not stop the fire. This had led to a significant number of fatal accidents in theatrical projection booths, where the heat of the projector lamp made ignition most likely. As the amateur filmmaking market slowly developed at the beginning of the 20th century, Kodak began to develop a more heat-resistant "safety base" which could be easily projected without incident even at home by those with no prior experience. Early tests in 1909 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. In the wake of the availability of safety film, more amateur formats began to adopt it, and several, including Kodak's own 16 mm format, were designed specifically so that the only film stocks released for the format specifications would be safety base.

Kodak also continued to refine their camera negative stock during the late 1910s, releasing 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, it has been suggested that the improvements most likely were in regards to granularity and sharpness.

1920s The 1920s proved to be the decade in which film stock manufacturers began to diversify their offerings. Prior to this, each manufacturer only offered one negative stock (usually orthochromatic) and one print stock. In 1920, a variant of Type F film known as X-back was created in order to counteract the effects of static electricity on the film, which can cause sparking and create odd exposure patterns on the film. This was created through the use of a resin backing on the film, which also had the effect of rendering the film too opaque to allow focusing through the back of the film - a common technique for many of the contemporary cameras of that era. As the static electricity was more likely to occur in colder climates, the X-back stock was mainly popular in the East Coast of the US. Other manufacturers also began to emerge in the 1920s as well, including American E.I. Dupont de Nemours in 1926 and Belgian Agfa-Gevaert in 1925.

Conversion of the industry from orthochromatic to panchromatic stocks was initiated by Kodak over the course of the decade. First used for exterior sequences in The Last of the Mohicans (1920 film) in 1920 and originally only available as a special order product, the stock's increased sensitivity in the red-light range meant greater overall light sensitivity and made it an attractive option for day for night shooting. Kodak financed a feature in 1922 shot entirely with the panchromatic stock, The Headless Horseman (1922 film), in order to promote the stock when it was introduced as a standard option; however, the fairly higher price of the stock compared to the orthochromatic emulsion meant that no other films would shot entirely with the panchromatic stock for several years. The cross-cutting between panchromatic and orthochromatic stocks also was noted to cause continuity problems particularly with regard to costume tones, and thus was often avoided. The dominance of orthochromatic film lasted until the mid 1920s due to Kodak's lack of competition in the panchromatic market; Gevaert emerged onto the market in 1925 with a dual product line of an orthochromatic stock with limited color sensitivity as well as a full panchromatic stock, Pan-23. This latter product likely encouraged Kodak to respond, and in 1926 they lowered the price of panchromatic stock to parity with the standard orthochromatic offering. Without any economic barrier remaining, the panchromatic stock began to overtake the orthochromatic stock's market share within a few years, as the cinematographers gradually became more familiar with the stock.There was apparently some question as to differences in relative contrast between the two stocks. As Barry Salt notes, "this claim is almost impossible to substantiate now, given the extreme difficulty there is in seeing a reasonable number of original prints of films shot on both stocks." (Salt, Film Style and Technology: History and Analysis, p. 179) With similar panchromatic offerings also made around the same period by Agfa and Pathe, the shift to panchromatic stocks had largely been completed by 1928.

Colour films Experiments with colour films were made as early as the late 19th century, but practical colour emulsions for professional use were not produced until shortly before the Second World War, and amateur film stock later.

The Technicolor process, which simultaneously exposed 3 frames of monochromatic cinematographic film through 3 colour filters, did not need an actual colour emulsion.

Classification and properties There are several variables in classifying stocks; in practice, one orders raw stock by a code number, based on desired sensitivity to light.

Base A piece of film consists of a light-sensitive emulsion applied to a tough, transparent film base, sometimes attached to anti-halation backing or "rem-jet" layer (now only on camera films). Originally the highly flammable Nitrocellulose 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 and by 1955 internationally. Since the late 1990s, almost all release prints have used polyester film stock.

Emulsion The emulsion is comprised of silver halide grains suspended in a gelatin colloid; in the case of color film, there are three layers of silver halide which are mixed with color couplers and interlayers which filter specific light spectra. These end up creating yellow, cyan, and magenta layers in the negative after development.

Chemistry Development chemistry applied to an appropriate film can produce either a positive (showing the same densities and colours as the subject) or negative film (with dark highlights, light shadows, and, in principle, complementary colours). 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 projector 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 alo be done by scanner 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 orthochromatic 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 film gauge and the arrangement of its film perforations— gauges range from 8 mm film to 70 mm film 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 mm film, 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 speed, determined by American Standards Association 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 film grain 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 or cross processing), 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 balance, which is defined by the color temperature at which it accurately records white. Tungsten lighting is defined at 3200 K, which is considered "warmer" in tone and shifted towards orange; daylight is defined at 5500 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. Obversely, 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 Motion picture film is known to be a highly unstable medium: improperly preserved film can deteriorate in a period of time much faster than many photographs or other visual presentations. Owners of home-made films often find that their film can become brittle and unwatchable in the space of a few years. Decaying acetate film stock gives off an odor similar to that of vinegar, which is why film buffs often refer to such decaying as "vinegar syndrome."

Intermediate and print stocks The distinction between camera stocks and print stocks involves a difference in the recording process. When the work print or edit master has been approved, the original camera negative (OCN) is assembled by a negative cutter using the edited work print or EDL (edit decision list) as a guide. An answer print is then made from the cut negative. During the answer print stage, corrections in the film's density and color are corrected (timed) to the filmmakers' tastes. Interpositive (IP) prints are struck from the answerprint, checked to make sure they look the same as the custom timed answer print and each IP is then used to make one or more Dupe Negative (DN) copies. The release prints are then generated from the DN(s). Recently, with the development of digital intermediate (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

Notes

References

External links

This article is mainly concerned with motion picture film. For still photography film, please see photographic film. Film stock is the term for photographic film on which Film are shot and reproduced.

History 1889-1899 Modern motion picture film stock was first created thanks to the introduction of a transparent flexible film base material, celluloid, which was discovered and refined for photographic use thanks to the work of John Carbutt, Hannibal Goodwin, and George Eastman. Prior to this, most motion picture experiments were performed using paper roll film, which made it difficult if not impossible to view the developed film as a single continuous moving image without other complex apparatuses. Furthermore, the paper film was much more fragile than celluloid.

Eastman Kodak would become the first to make celluloid film commercially available, starting in 1889; Thomas Henry Blair emerged in 1891 as the first major competitor for supplying celluloid film. The stock had a frosted base in order to facilitate easier viewing by transmitted back light, and the emulsions from each company were orthochromatic. By November 1891 William Dickson (film pioneer) at Edison's lab was using Blair's stock for Kinetoscope tests, and Blair's company remained a main supplier of film to the Edison lab for the next five years. Blair's operation was also crucial to the continued development of motion picture technology through 1892 and 1893, due to temporary shutdowns at Eastman because of problems with their production setup. Eventually patent lawsuits in 1893 led to Blair leaving his American company and starting again in England, which allowed Eastman to gradually fill the entirety of the Edison lab's film orders. Blair's new headquarters allowed him to supply many of the key European filmmaking pioneers, including Birt Acres, Robert Paul, George Albert Smith, Charles Urban, and the Lumiere Brothers. The American Blair company was to be shortlived, however, as by 1896 the new movie projector would demand a fully transparent film base that they had difficulty supplying. Eastman shortly thereafter bought the company out, thus consolidating its position as the leading supplier of film stock from then on. These developments also led Louis Lumiere to work with Victor Planchon on adapting the Lumiere "Blue Label" (Etiquette Bleue) photographic plate emulsion for use on celluloid roll film, which began in early 1896 and was brought to full production capacity by the following year.

Eastman's first motion picture film stock incorporated the same emulsion as was used for its still film, which was, like nearly all film emulsion of the time, orthochromatic-sensitive. Film at this point did not have a strictly defined speed; rather, the orthochromatic quality of the stock allowed the film to be processed under a red safelight, while the density was checked as development was occurring. Standard practice until the end of the silent film involved tearing off several inches from the start of each shot and testing development on it. Positive stock was created which would be slower, finer-grained, and of a higher contrast than a negative; all of these characteristics remain consistent to this day.

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, but this was largely undesirable by most narrative filmmakers. Actuality films 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 James J. Jeffries-Tom Sharkey fight on November 3, 1899.

1900-1919 Work on improved film stocks was rather slow in the first decade of the new century, as the equipment and list of film formats, particularly, were still in the process of gradually standardizing. With a large number of differing film gauges in use, supplying a market still in its infancy was likely a difficult task, and Eastman was able to retain the majority of the market share without making major adjustments to the emulsion; their only major change was to increase the length of rolls to 200 feet. Lumiere, on the other hand, reformulated their stock to match the speed of Eastman film, which became known as "Violet Label" (Etiquette Violette). Blair retired back to the United States after selling his English company to Pathe in 1907, who began using the facilities for producing their own film stock. This sale had future repercussions among film preservation, as Pathe began to supplement their operation in 1910 by purchasing film prints in order to strip the silver and emulsion from the film base for recoating.

As the quantity of film and filmmakers grew in these early years, the demand for standardization increased in prominence. 35 mm film, largely thanks to the popularity of the Edison and Lumiere camera lines (and their often unauthorized clones) had begun to stabilize as the dominant gauge, but still was usually purchased unperforated, and subsequently punched by the consumer with perforation equipment designed by third parties. Although Edison (4 square perfs per frame on each side) and Lumiere (1 rounded perf per frame on each side) formats - based on the camera designs - were the most common, the perforators were not always precise, and it could be difficult to create prints for the opposite perforation format. Edison's organization of the Edison Trust, though largely ineffective in controlling the burgeoning film industry, was able in 1909 to agree to what would become the de facto standard: 35 mm gauge, with Edison perforations and a 1.33 aspect ratio (image). These parameters have remained largely constant to the present day.The gauge and perforations are more or less identical to modern film stock; the full silent ratio is also generally still used as the film gate in movie cameras, although portions of the image are later cropped out in post-production and projection.

The Bell and Howell company perforators entered the market in 1908 and very shortly were recognized as exceptional enough to pervade the American industry. Eastman Kodak was also quick to opt to use the machine to pre-perforate their films, which assured the perforation specifications being adopted as the world standard not long after. These perforations, known as BH-type, remain the standard for original camera negative film.

The belle epoque era also saw the creation of numerous small, local film suppliers, the vast majority of which were short-lived due to their smaller production batches, slower emulsions (which were also usually blue-only sensitive rather than orthochromatic), and inferior quality control. Among these companies, Agfa began to produce motion picture film in 1913, but remained a largely local supplier until post-World War I boycotts of popular French films allowed the newly-founded Universum Film AG film studio to flourish and thus boosted Agfa's orders.

Among the foremost problems with the film stocks of this era was that they were all manufactured on a nitrocellulose film base, which was a derivate of guncotton and thus highly flammable. Additionally, nitrate fires were notoriously difficult to put out, as even full submersion in water will not stop the fire. This had led to a significant number of fatal accidents in theatrical projection booths, where the heat of the projector lamp made ignition most likely. As the amateur filmmaking market slowly developed at the beginning of the 20th century, Kodak began to develop a more heat-resistant "safety base" which could be easily projected without incident even at home by those with no prior experience. Early tests in 1909 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. In the wake of the availability of safety film, more amateur formats began to adopt it, and several, including Kodak's own 16 mm format, were designed specifically so that the only film stocks released for the format specifications would be safety base.

Kodak also continued to refine their camera negative stock during the late 1910s, releasing 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, it has been suggested that the improvements most likely were in regards to granularity and sharpness.

1920s The 1920s proved to be the decade in which film stock manufacturers began to diversify their offerings. Prior to this, each manufacturer only offered one negative stock (usually orthochromatic) and one print stock. In 1920, a variant of Type F film known as X-back was created in order to counteract the effects of static electricity on the film, which can cause sparking and create odd exposure patterns on the film. This was created through the use of a resin backing on the film, which also had the effect of rendering the film too opaque to allow focusing through the back of the film - a common technique for many of the contemporary cameras of that era. As the static electricity was more likely to occur in colder climates, the X-back stock was mainly popular in the East Coast of the US. Other manufacturers also began to emerge in the 1920s as well, including American E.I. Dupont de Nemours in 1926 and Belgian Agfa-Gevaert in 1925.

Conversion of the industry from orthochromatic to panchromatic stocks was initiated by Kodak over the course of the decade. First used for exterior sequences in The Last of the Mohicans (1920 film) in 1920 and originally only available as a special order product, the stock's increased sensitivity in the red-light range meant greater overall light sensitivity and made it an attractive option for day for night shooting. Kodak financed a feature in 1922 shot entirely with the panchromatic stock, The Headless Horseman (1922 film), in order to promote the stock when it was introduced as a standard option; however, the fairly higher price of the stock compared to the orthochromatic emulsion meant that no other films would shot entirely with the panchromatic stock for several years. The cross-cutting between panchromatic and orthochromatic stocks also was noted to cause continuity problems particularly with regard to costume tones, and thus was often avoided. The dominance of orthochromatic film lasted until the mid 1920s due to Kodak's lack of competition in the panchromatic market; Gevaert emerged onto the market in 1925 with a dual product line of an orthochromatic stock with limited color sensitivity as well as a full panchromatic stock, Pan-23. This latter product likely encouraged Kodak to respond, and in 1926 they lowered the price of panchromatic stock to parity with the standard orthochromatic offering. Without any economic barrier remaining, the panchromatic stock began to overtake the orthochromatic stock's market share within a few years, as the cinematographers gradually became more familiar with the stock.There was apparently some question as to differences in relative contrast between the two stocks. As Barry Salt notes, "this claim is almost impossible to substantiate now, given the extreme difficulty there is in seeing a reasonable number of original prints of films shot on both stocks." (Salt, Film Style and Technology: History and Analysis, p. 179) With similar panchromatic offerings also made around the same period by Agfa and Pathe, the shift to panchromatic stocks had largely been completed by 1928.

Colour films Experiments with colour films were made as early as the late 19th century, but practical colour emulsions for professional use were not produced until shortly before the Second World War, and amateur film stock later.

The Technicolor process, which simultaneously exposed 3 frames of monochromatic cinematographic film through 3 colour filters, did not need an actual colour emulsion.

Classification and properties There are several variables in classifying stocks; in practice, one orders raw stock by a code number, based on desired sensitivity to light.

Base A piece of film consists of a light-sensitive emulsion applied to a tough, transparent film base, sometimes attached to anti-halation backing or "rem-jet" layer (now only on camera films). Originally the highly flammable Nitrocellulose 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 and by 1955 internationally. Since the late 1990s, almost all release prints have used polyester film stock.

Emulsion The emulsion is comprised of silver halide grains suspended in a gelatin colloid; in the case of color film, there are three layers of silver halide which are mixed with color couplers and interlayers which filter specific light spectra. These end up creating yellow, cyan, and magenta layers in the negative after development.

Chemistry Development chemistry applied to an appropriate film can produce either a positive (showing the same densities and colours as the subject) or negative film (with dark highlights, light shadows, and, in principle, complementary colours). 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 projector 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 alo be done by scanner 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 orthochromatic 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 film gauge and the arrangement of its film perforations— gauges range from 8 mm film to 70 mm film 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 mm film, 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 speed, determined by American Standards Association 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 film grain 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 or cross processing), 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 balance, which is defined by the color temperature at which it accurately records white. Tungsten lighting is defined at 3200 K, which is considered "warmer" in tone and shifted towards orange; daylight is defined at 5500 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. Obversely, 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 Motion picture film is known to be a highly unstable medium: improperly preserved film can deteriorate in a period of time much faster than many photographs or other visual presentations. Owners of home-made films often find that their film can become brittle and unwatchable in the space of a few years. Decaying acetate film stock gives off an odor similar to that of vinegar, which is why film buffs often refer to such decaying as "vinegar syndrome."

Intermediate and print stocks The distinction between camera stocks and print stocks involves a difference in the recording process. When the work print or edit master has been approved, the original camera negative (OCN) is assembled by a negative cutter using the edited work print or EDL (edit decision list) as a guide. An answer print is then made from the cut negative. During the answer print stage, corrections in the film's density and color are corrected (timed) to the filmmakers' tastes. Interpositive (IP) prints are struck from the answerprint, checked to make sure they look the same as the custom timed answer print and each IP is then used to make one or more Dupe Negative (DN) copies. The release prints are then generated from the DN(s). Recently, with the development of digital intermediate (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

Notes

References

External links



Filmstock - Luton International Film Festival
UK-based international film festival.

Film stock - Wikipedia, the free encyclopedia
Film stock is photographic film on which motion pictures are shot and reproduced.

BBC - Film
The Film Programme: Francine Stock and star guests on the latest cinema releases, DVDs and films on TV.

Film Stocks
Current Products. Kodak: 01442 845945 http://www.kodak.com Fuji: 0207 586 5900 http://www.motion.fuji.co.uk/motionproducts/index.html

London's Only Shop to Buy Telescopes & Telescope Accessories, Stumpfl ...
Standard 8 Color Ektachrome 100ASA and SUPER 8 CAMERAS are back soon! Super 8 mm, Standard 8 & 16 mm - cameras, film stock, processing and on-site Telecine Service (a fully graded ...

Bradford Movie makes,one of the oldest amateur film making clubs in ...
Historically we are one of the oldest amateur film making clubs in this country. A small group working with black and white 16mm film stock, founded the Bradford Cine Circle in ...

The Standard Eight Film Co - Film Stock Page
This is the official website for Standard 8 Film Making. ... Film Stocks Fomapan R100 Fuji Velvia Kodak Ektachrome 100D Kodak Tri-X Kodak Plus-X

SourceForge.net: Film Stock Calculator
The world's largest development and download repository of Open Source code and applications ... The Film Stock Calculator is an application for calculating the film stock footage ...

Film Stock Calculator™
The Film Stock Calculator provides an easy method for calculating the film stock footage and cost for a film.

The Knowledge Online: Film Stock & Videotape / Archives
The definitive UK source of contacts within the TV, video and film production industries: Film Stock & Videotape

 

Film Stock



 
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