Celluloid film
Celluloid film (also called nitrofilm ) is a photographic film with celluloid as the starting material for the carrier of the image layer , the so-called celluloid base. It replaced the previously common glass plates .
History and Development
George Eastman is often cited as the inventor of celluloid film , but this is incorrect. Eastman presented for the first time in 1891, according to some sources in 1889, a coated roll film based on the "Celluloïds" developed by John Wesley Hyatt , the so-called American film . He had bought this partly from William Walker and partly had it developed by Henry Reichenbach . Eastman's American Film is a further development of the 1884 Stripping film , a paper film .
The flexible, colorless, transparent film, however, was invented and patented by the clergyman Hannibal Goodwin as early as 1887 . A legal dispute ensued that lasted until 1898. In the meantime, Eastman was building his photographic empire.
After a long-standing priority dispute, Goodwin was granted US patent 610,861 on September 13, 1898 as valid. The Eastman Kodak Corporation had to pay Goodwin millions in compensation. The US patent 417,202 of December 10, 1889 to Henry M. Reichenbach of the Eastman Dry Plate and Film Company is also after Goodwin's application.
The nitrate-based film carriers used from the end of the 19th century until well into the 1950s pose an acute threat to photo collections and historical film archives .
Nitrocellulose is made with sulfuric and nitric acid from cotton scraps, so-called linters . This highly explosive mixture is nothing more than gun cotton and has a higher explosive power than black powder . That is why films with nitrocellulose carriers are now subject to the Federal Explosives Act .
Films containing cellulose nitrate burn instantly, almost explosively, when they come into contact with heat sources. If the film stops in front of the hot projection lamp, this can have very unpleasant consequences. For safety reasons, there used to be a strict transport ban on celluloid cinema films on many public transports. The Deutsche Bundespost also only accepted films for delivery since they were no longer made of celluloid. Officially from January 1, 1951, the so-called security film replaced the celluloid film in Europe . Polyester film has also been used since 1950, and in broad circles since the 1980s .
In Germany, from April 1, 1940, only security film was to be used instead of celluloid film in film production. The Second World War prevented this, however.
Natural aging is also problematic with celluloid film, which affects not only the photo emulsion but also the carrier. In the past, the problem was dealt with by copying onto security film (with corresponding losses with every copying process), provided the content justified this effort. Since around 2001 the photographic losses have been so low that the classic archive technology is still justified. In addition, the transfer to a digital intermediate allows not only the permanent restoration of historical film material using electronic image processing , but also loss-free copying for backup purposes .
In the films Cinema Paradiso and Inglourious Basterds , the flammability of celluloid film is the topic.
storage
If the nitrate film is stored at 21 ° C and a relative humidity of 50%, a service life of up to 40 years can be assumed. With a deep freezing of - 18 ° C even more than 400 years should be possible.
decomposition
Five stages of decomposition can be distinguished in nitrate films.
- Stage 1 : The film has an amber discoloration and the image is faded. A slightly sour odor can be detected. Sheet metal film containers have a rust ring where the film has been in place for a long time.
- Stage 2 : The carrier material becomes sticky, the film strips stick together when unrolled. A slightly sour odor can be detected.
- Stage 3 : Parts of the film become soft and contain gas bubbles. A sour smell is spread.
- Stage 4 : The roll of film bakes together into a single, soft mass. The surface can have a viscous foam. A strongly sour, unhealthy odor is spread.
- Stage 5 : The film degenerates into a shock-sensitive, brown powder.
Films in stages 1 and 2 can still be copied. This may require special machines that do not intervene in the perforation of the already warped, wavy film, but manage the transport differently.
See also
Web links
- Identify and discard nitrate films
- Images of nitrate films in various stages of decomposition
- Information from the Federal Archives
Individual evidence
- ↑ Reinhard Welz, Siegfried Sommer, et al. (Ed.): Technology knowledge 1900-1915: Kleines Technik-Lexikon ES . Reinhard Welz Vermittler Verlag, Mannheim 2003, ISBN 3-937081-06-2 , p. 159 .
- ↑ Long-term archiving of nitrate films
- ^ Safe Handling, Storage, and Destruction of Nitrate-Based Motion Picture Films