Community hub
Recent from talks
Contribute something to knowledge base
Content stats: 0 posts, 0 articles, 0 media, 0 notes
Members stats: 0 subscribers, 0 contributors, 0 moderators, 0 supporters
Subscribers
Supporters
Contributors
Moderators
Hub AI
Film base AI simulator
(@Film base_simulator)
Hub AI
Film base AI simulator
(@Film base_simulator)
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. Since the late 19th century, there have been three major types of film base in use: nitrate (until about 1951), acetate, and polyester.
In the literature of photography, "nitrate" is used as a synonym for the chemical nitrocellulose. It is also referred to as "cellulose nitrate". Nitrocellulose is guncotton, the first replacement propellant for gun powder in firearms.
Film stock with a nitrate base was the first transparent flexible plasticized base commercially available, thanks to celluloid developments by John Carbutt, Hannibal Goodwin, and Eastman Kodak in the 1880s. Eastman was the first to manufacture the film stock for public sale, in 1889. Unfortunately, nitrate also had the serious drawback of being extremely flammable, the characteristic that made it a suitable substitute for gunpowder. It gradually decomposes producing a flammable gas, becomes sticky and, at a late stage of decomposition, the film oozes a gooey fluid, ultimately leading the substance to become dust. As this occurs, the possibility of auto-ignition increases further.
Projection booth fires were not uncommon in the early decades of cinema if a film managed to be exposed to too much heat while passing through the projector's film gate, and several incidents of this type resulted in audience deaths by flame, smoke, or the resulting stampede. An accidental fire caused by the film jamming in the gate formed a significant plot point in the movie Cinema Paradiso (1988).
The year 1978 was particularly devastating for film archives when both the United States National Archives and Records Administration and George Eastman House had their nitrate film vaults auto-ignite. Eastman House lost the original camera negatives for 329 films, while the National Archives lost 12.6 million feet (3.84 million meters, or very roughly the distance between the two coasts of the continental United States) of newsreel footage. Because cellulose nitrate contains oxygen, nitrate fires are impossible to extinguish. The US Navy has produced an instructional movie about the safe handling and usage of nitrate films which includes footage of a full reel of nitrate film burning under water. The base is so flammable that intentionally igniting the film for test purposes is recommended in quantities no greater than one frame without extensive safety precautions. The smoke produced by burning nitrate film is highly toxic, containing several poisonous gases and can become lethal if inhaled enough.
Many nitrate films have been transferred in recent decades to safety stock, and original nitrate prints are generally stored separately to prevent a nitrate fire from destroying other non-nitrate films; the gas they release also affects the emulsion of safety film. Usually nitrate collections are even split up into several different fireproof rooms to minimize damage to an entire collection should a fire occur in one part. It is normal for a theater today to pass rigorous safety standards and precautions before being certified to run nitrate films; this includes a fireproof projection booth, fire chambers surrounding the feed and take-up reels, and several fire extinguishers built into the projector and aimed at the projector's film gate with a trigger released if the film ignites. Nitrate film is classified as "dangerous goods", which requires licenses for storage and transportation.
Nitrate film stock was used in every major film production before about 1951. Many silent films only survived because they were printed to 16 mm film, which did not use a nitrate base. A report published by the United States Library of Congress in September 2013 states that 70 percent of all American silent feature films are lost.
In the literature of photography "acetate" is used as a synonym for several chemicals: cellulose acetate, cellulose triacetate, cellulose diacetate, cellulose acetate propionate, and cellulose acetate butyrate. All have been used separately and in mixtures, to produce 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. Since the late 19th century, there have been three major types of film base in use: nitrate (until about 1951), acetate, and polyester.
In the literature of photography, "nitrate" is used as a synonym for the chemical nitrocellulose. It is also referred to as "cellulose nitrate". Nitrocellulose is guncotton, the first replacement propellant for gun powder in firearms.
Film stock with a nitrate base was the first transparent flexible plasticized base commercially available, thanks to celluloid developments by John Carbutt, Hannibal Goodwin, and Eastman Kodak in the 1880s. Eastman was the first to manufacture the film stock for public sale, in 1889. Unfortunately, nitrate also had the serious drawback of being extremely flammable, the characteristic that made it a suitable substitute for gunpowder. It gradually decomposes producing a flammable gas, becomes sticky and, at a late stage of decomposition, the film oozes a gooey fluid, ultimately leading the substance to become dust. As this occurs, the possibility of auto-ignition increases further.
Projection booth fires were not uncommon in the early decades of cinema if a film managed to be exposed to too much heat while passing through the projector's film gate, and several incidents of this type resulted in audience deaths by flame, smoke, or the resulting stampede. An accidental fire caused by the film jamming in the gate formed a significant plot point in the movie Cinema Paradiso (1988).
The year 1978 was particularly devastating for film archives when both the United States National Archives and Records Administration and George Eastman House had their nitrate film vaults auto-ignite. Eastman House lost the original camera negatives for 329 films, while the National Archives lost 12.6 million feet (3.84 million meters, or very roughly the distance between the two coasts of the continental United States) of newsreel footage. Because cellulose nitrate contains oxygen, nitrate fires are impossible to extinguish. The US Navy has produced an instructional movie about the safe handling and usage of nitrate films which includes footage of a full reel of nitrate film burning under water. The base is so flammable that intentionally igniting the film for test purposes is recommended in quantities no greater than one frame without extensive safety precautions. The smoke produced by burning nitrate film is highly toxic, containing several poisonous gases and can become lethal if inhaled enough.
Many nitrate films have been transferred in recent decades to safety stock, and original nitrate prints are generally stored separately to prevent a nitrate fire from destroying other non-nitrate films; the gas they release also affects the emulsion of safety film. Usually nitrate collections are even split up into several different fireproof rooms to minimize damage to an entire collection should a fire occur in one part. It is normal for a theater today to pass rigorous safety standards and precautions before being certified to run nitrate films; this includes a fireproof projection booth, fire chambers surrounding the feed and take-up reels, and several fire extinguishers built into the projector and aimed at the projector's film gate with a trigger released if the film ignites. Nitrate film is classified as "dangerous goods", which requires licenses for storage and transportation.
Nitrate film stock was used in every major film production before about 1951. Many silent films only survived because they were printed to 16 mm film, which did not use a nitrate base. A report published by the United States Library of Congress in September 2013 states that 70 percent of all American silent feature films are lost.
In the literature of photography "acetate" is used as a synonym for several chemicals: cellulose acetate, cellulose triacetate, cellulose diacetate, cellulose acetate propionate, and cellulose acetate butyrate. All have been used separately and in mixtures, to produce film base.