Movietone sound system
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The Movietone sound system is an
History
As a student, Theodore Case became interested in the use of modulated light to carry speech, and in 1916 set up a laboratory to study the photo-electric properties of materials. He developed the Thalofide cell, a sensitive photocell, which was used as part of an infrared communication system by the U.S. Navy during, and for some years after WW1.
In 1922 Case and his assistant Earl I. Sponable turned their attention to "talking pictures". In that same year Case was approached by Lee de Forest who had been attempting since 1919 to create an optical soundtrack for motion picture film in a system he called Phonofilm. De Forest was having little success and turned to Case for help, so from 1922 until 1925 Case and de Forest collaborated in the development of the Phonofilm system. Amongst other Case inventions Case contributed the Thalofide photocell and also the Aeo-light, a light source that could be readily modulated by audio signals and was used to expose the soundtrack in sound cameras.
In 1925, however, Case ended his relationship with de Forest due to de Forest's tendency to claim the entire credit for the Phonofilm system for himself despite the fact that most of the critical inventions had come from Case. Documents supporting this, including a signed letter by De Forest that states that Phonofilms are only possible because of the inventions of Case Research Lab, are located at the Case Research Lab Museum in Auburn, New York.[2] In 1925, therefore, Case and Sponable continued the development of their own system, now called "Movietone".
From 1924 onwards Sponable had turned his attention to the design of single-system cameras, in which the sound and picture are recorded on the same negative. He asked Bell & Howell to modify one of their cameras to his design, but the results were unsatisfactory. Consequently, the Wall machine shop in Syracuse, New York was asked to rebuild this camera and the results were much improved.
Subsequently, many single-system 35mm cameras were produced by Wall Camera Corporation, which much later produced the three-film Cinerama cameras. Wall initially converted some Bell & Howell Design 2709 cameras to single-system, but most were Wall designed and produced. Single-system cameras were also produced by Mitchell Camera Corporation during World War II for the U.S. Army Signal Corps, although these cameras were quite rare.
Partly as a result of the single system experiments, the aspect ratio of approximately 1.19:1 that is created by printing an optical soundtrack on top of the 35mm full aperture became known colloquially as the "Movietone ratio". It was used extensively by Hollywood and European studios (apart from those that adopted sound-on-disc) between the late 1920s and May 1932, when the Academy ratio of 1.37:1 was introduced to restore the effective shape of the silent frame.
The 1950s brought the first 35mm kinescope camera with sound-on-film rather than separate, from Photo-Sonics, with a Davis Loop Drive mechanism built within the camera box. This camera was essential for TV network time-shifting in the years before Videotape. The sound galvanometer was made by RCA and was designed for good to excellent results when the kinescope negative was projected, thereby avoiding making a print before the delayed replay. The Davis mechanism was a Western Electric development.
After the split with de Forest, Case adopted a revised position for the projector soundhead, which was now placed below the picture head, with a sound-picture offset of 14+1⁄2 inches (370 mm) (which is close to the present day standard), rather than being placed above the picture head as had been the phonofilm practice. Case also adopted the 24 frames/sec speed for Movietone, bringing it in line with the speed already chosen for the Western Electric Vitaphone sound-on-disc system, and thus establishing 24 frames/sec as the standard speed for all sound films, whether sound-on-disc or sound-on-film. With a few exceptions, this has remained the standard speed for professional sound films ever since.[3][4]
At this point, the Movietone system was adopted by the
Commercial use by William Fox
Movietone entered commercial use when
Less than two years after purchasing the system from Case, Fox bought out all of Case's interests in the Fox-Case company. All of Fox's sound feature films were made using the Movietone system until 1931 when it was superseded by a Western Electric recording system using the light-valve invented by Edward C. Wente in 1923. However, Fox Movietone News used the system until 1939, because of the ease of transporting the single-system's sound film equipment.
Later development
The Case Research Lab sound system influenced many industry standards, such as positioning the
This was done partly to ensure the film runs smoothly past the sound head, but also to prevent Phonofilms from being played in theaters – as the Phonofilm system was incompatible with Case Research Lab specifications – and to ease the modification of projectors already widely in use.Sponable worked at the
The history of Case Research Lab was long unheralded. Theodore Case died in 1944 and donated his home and laboratory to be preserved as a museum for the inventions of Case Research Lab. The museum's first director, who oversaw it for 50 years, put the laboratory's contents into storage and converted the building into an art studio. The Case Research Lab sound studio was located on the second floor of the estate's carriage house which was rented to a local model train club until the early 1990s.
Fox was seriously injured in a July 1929 car accident, lost his company in 1930 when his loans were called in, and lost the 1936 lawsuit in the U.S. Supreme Court against the film industry for violating his Tri-Ergon patents. Sponable did little to establish the record of Case Research Lab inventions, other than his April 1947 article in The Journal of the SMPE.
It was also in 1947 that the Davis Loop Drive was introduced to Western Electric licensees, including Twentieth Century-Fox (WECo RA-1231; still made by a successor company). [citation needed]
Case Research Lab, the adjoining carriage house, and Case's home have been restored and research is ongoing with the lab receipts, notebooks, correspondence, and much of the laboratory's original equipment, including the first recording device created to test the AEO light. The collections have letters from Thomas Edison, a copy of the Tri-Ergon patents, and an internal document from Fox Films written in the 1930s. This latter document says that once it became public knowledge that Sponable perfected the variable-area system of sound-on-film at the Fox Studios, that system became the standard and superseded the inventions of Case Research Lab.
A number of films owned by Case Research Lab and Museum were restored by
Phonofilms that were produced using Case Research Lab inventions are in the collections of the Library of Congress and the British Film Institute.
The variable density (VD) recording systems developed from Movietone gradually lost market share to variable area (VA) systems developed from Photophone after the 1940s, a process that gathered pace as VA-related patents expired. Though both methods can theoretically achieve similar standards of recording, duplication and reproduction, quality control in the lab proved to be far more critical in the duplication of VD than VA tracks: slight errors in printer light settings and sensitometry and densitometry control will affect the signal-to-noise ratio of a VD track far more than a VA one. For this reason archives have tended to remaster original VD tracks to VA negatives for preservation and the creation of new prints.
See also
- Phonofilm
- Vitaphone
- RCA Photophone
- Photokinema
- Movietone News
- Joseph Tykociński-Tykociner
- Eric Tigerstedt
- Sound film
- Movie projector
- Sound-on-disc
- List of film formats
- List of early sound feature films (1926–1929)
References
- ^ "Motion Picture Sound - part 1". Audio Engineering Society. 2017-07-01. Archived from the original on 2017-07-01. Retrieved 2021-01-02.
- ^ "Cayuga Museum of History and Art". Retrieved 2021-01-02.
- ^ a b c Earl I. Sponable, "Historical Development of Sound Films", The Journal of the Society of Motion Picture Engineers (April 1947), Vol. 48, No. 4
- ^ a b Edward Kellogg, "History of Sound Motion in Pictures", The Journal of the Society of Motion Picture Engineers (June 1955), Vol. 64, p. 295
- ^ Leslie J. Wheeler, Principles of Cinematography (4th ed.), Fountain Press (1969), p. 373
- ^ Kodak Film Notes Issue # H-50-03: Projection practices and techniques – see Manuals at http://www.film-tech.com/
- ^ Ira Konigsberg, The Complete Film Dictionary (2nd ed.), Bloomsbury (1997) – see Projector article.