User:Girolamo Savonarola/stock

1889-1894: Celluloid beginnings
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 coated with collodion, 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. Thomas Edison's lab, under the direction of William Dickson, began ordering celluloid photographic sheets from Carbutt in June 1889, which were wrapped around a cylindrical apparatus used in the earlier stages of the development of the Kinetoscope. Edison's subsequent trip to France in August 1889 included a meeting with chronophotographer Etienne-Jules Marey, and led Edison's conceptual design work to focus on a roll of film moved intermittently by means of perforations and sprockets. Dickson was particularly glad to embrace roll film, as the strip of film promised much greater shot lengths than cylindrical or disc systems, both of which were limited to exposing their surface areas. Additionally, moving the film off of a cylinder onto a flat plane reduced distortion and improved image resolution.

This decision to shift the photographic system towards roll film made Eastman Kodak well-positioned to take a dominant role in the inception of motion pictures. George Eastman invented the concept in 1884 in order to allow existing professional still photographers to quickly take multiple exposures, and the convenience of the system led to the opening of the amateur stills market in 1887 with the "Kodak No. 1". Although Eastman had been experimenting with celluloid since the early 1880s, the introduction of photographic celluloid by Carbutt and others spurred intensive research in 1888 led by chemist Henry Reichenbach. Upon making patent applications in the spring of 1889, Eastman Kodak announced in June that they would become the first company to make celluloid roll film commercially available; however, the manufacturing process was almost immediately beset by defects including      static electricity crackles near the corners of the exposures and blistering of the film, all of which ultimately held back wide distribution of the Eastman celluloid roll film until spring 1890. Despite these setbacks, Dickson was eager to try out the new roll film, as he had run into difficulties implementing Edison's roll system by means of recutting Carbutt's film into strips in the summer of 1889. Eastman's new celluloid manufacturing process created a product which was both stronger and more flexible, which made it better suited to the speeds and stresses required for a motion picture roll film. Dickson claimed to have first received a roll from a company representative at a New York City demonstration in August 1889, although the first Edison records indicate an order in early September for a single roll of 3/4 inch (19 mm) film 50 feet long, followed by a dozen more before the end of the year.

Edison's return from abroad in late 1889 spurred him to refine his concept in order to explicitly include perforations and sprockets into the mechanisms, which led Dickson to begin ordering Eastman rolls 1 inch (25.4 mm) wide starting in February 1890. The additional width was necessary in order for Dickson trim the film to 3/4 inch with higher accuracy, which was prerequisite for more accurate perforation, which was also done in-house at Edison's lab. Following a successful demonstration of the new horizontal-feed Kinetoscope on May 20, 1891, Dickson met with Eastman in July at the film manufacturer's headquarters in Rochester to discuss changes to the Kinetoscope and problems the Edison lab had been encountering with the film stock, mainly regarding torn perforations and blurred images. To address these concerns, the next revision of the Kinetoscope would integrate a second row of perforations on the opposite edge of the film to increase image stability and would take larger images, requiring wider-gauge rolls. By late summer 1891, Dickson had settled on a rectangular image - in contrast to all previous formats taking a circular one - which he stipulated be 1 inch by 3/4 inch, establishing what would become the standard silent film aspect ratio of 1.33:1.

Thomas Henry Blair emerged in 1890 as the first major competitor for supplying celluloid film stock. 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 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.

1895-1899: Transparency and projection
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 era 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 Jeffries-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 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 Motion Picture Patents 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. These parameters have remained largely constant to the present day.

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 UFA 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 nitrate 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 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 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, 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. 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 color 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 color filters, did not need an actual color emulsion.