NationMaster - Encyclopedia: RCA Photophone

RCA Photophone was the trade name given to one of four major competing technologies that emerged in the American film industry in the late 1920s for synchronizing electrically recorded audio to a motion picture image. RCA Photophone was a "variable-area" film exposure system, in which the modulated area (width) corresponded to the amplitude of the audio signal. The three other major technologies were the Warner Brothers Vitaphone sound-on-disc system and two "variable-density" sound-on-film systems, Lee De Forest's Phonofilm, and Fox-Case's Movietone. This article is about motion pictures. ... A photograph with an exposure time of 25 seconds A photograph of a night-time sky with an exposure time of 8 seconds In photography, exposure is the total amount of light allowed to fall on the photographic medium (photographic film or image sensor) during the process of taking a... In telecommunications, modulation is the process of varying a periodic waveform, i. ... For quantum-mechanical amplitude, see probability amplitude. ... Sounding can refer to: Determination the depth of water usually in the sea. ... Warner Bros. ... The Warner Brothers Vitaphone logo. ... The term Sound-on-disc refers to a class of sound film processes utilizing a phonograph or other disc to record or playback sound in sync with a motion picture. ... Sound-on-film refers to a class of sound film processes where the sound accompanying picture is physically recorded onto photographic film, usually, but not always, the same film strip of film carrying the picture. ... Lee De Forest, (August 26, 1873 â€“ June 30, 1961) was an American inventor with over 300 patents to his credit. ... In 1919, Lee De Forest, inventor of the audion tube, filed his first patent on a sound-on-film process, DeForest Phonofilm, which recorded sound directly onto film as parallel lines. ... The Fox Film Corporation was an American company which produced motion pictures, formed in 1915 when founder William Fox merged two companies he had established in 1913: Greater New York Film Rental, a distribution firm, which was part of the Independents; and Fox (or Box, depending on the source) Office... Theodore Case (1888 Auburn, New York â€“ 1944) began working on his sound-on-film process in 1916. ... The Movietone sound system is method of recording sound for moving pictures which guarantees synchronisation between the sound and the picture. ...

The patent was awarded to General Electric (GE) in 1925, which dubbed the process Photophone, a name that had been used in previous decades for other sound film processes. RCA, a GE subsidiary, took over the patent as part of a corporate competition with AT&T/Western Electric, a primary sponsor of both Vitaphone and Movietone. GE redirects here. ... 1902 poster advertising Gaumonts sound films, depicting an optimistically vast auditorium A sound film is a motion picture with synchronized sound, or sound technologically coupled to image, as opposed to a silent film. ... This article is about the former RCA Corporation. ... This article is about the current AT&T. For the 1885-2005 company, see American Telephone & Telegraph. ... Company Masthead Logo Logo until circa 1969, also current logo on company web site Logo 1969â€“1983 Hi Dan! Western Electric (sometimes abbreviated WE and WECo) was an American electrical engineering company, the manufacturing arm of AT&T from 1881 to 1995. ...

Both variable-area and variable-density systems were marketed by both RCA and Western Electric, with equal measured and perceived quality from both systems and from both suppliers. Movietone News produced cinema newsreels from 1929-1979. ...

Neither system nor supplier was clearly superior to the others, except where individual laboratory processes made one system more consistently superior to the others.

Some laboratories could maintain the correct "gamma" required for variable-density, but couldn't maintain the correct gamma required for variable-area. Conversely, some laboratories could maintain the correct gamma required for variable-area, but couldn't maintain the correct gamma required for variable-density.

Variable-density was preferred for Technicolor prints as this process utilized a silver "key" record, thereby creating a CMYK color image, and the sound track was also a silver record. The "key" record was deleted from most Technicolor prints after 1944, thereby creating a CMY color image, but Technicolor's strong preference for variable-density continued long thereafter. Technicolor could consistently produce good variable-density tracks.

Variable-density was finally abandoned as customer preferences for "dual-bilateral variable-area" sound tracks emerged in the late-1950s. This required changes to laboratory processing and quality controls, but the real reason for variable-density's demise was yet to come.

In the mid-1970s, Westrex Corp (Litton Industries' wholly-owned subsidiary, and the successor to Western Electric's cinema sound business unit) re-introduced the ca. 1938 "four ribbon" light valve, and the ca. 1947 RA-1231 sound recorder.

As the RA-1231 was actually a stereo variable-area recorder (although when it was originally introduced in 1947 it was a mono 35mm variable-density or variable-area recorder, or a 16mm variable-density or variable-area recorder, at the customer's option) variable-density's fate was sealed as stereo optical prints became a marketing imperative.

When combined with Dolby's encoding technology, the discrete L and R channels of Westrex's stereo variable-area system was renamed "Left Total" and "Right Total", and when decoded these produced the L, C, R and S sound image first popularized by Fox's CinemaScope system in 1953.

Nearly all OTNs (original track negatives) are now produced as stereo variable-area, and the former Western Electric (Westrex) system has been renamed Photophone and has become the defacto standard, world-wide.

The RCA system was abandoned as it was incapable of producing time-aligned stereo OTNs, whereas time-aligned stereo OTNs were inherently a part of the Western Electric (Westrex) system since 1938.

The Western Electric (Westrex) system was renamed Photophone after the Western Electic and Westrex registered trademarks were sold by AT&T and Litton, respectively, to others, for uses other than cinema sound systems.

Renaming the Westrex system to Photophone was facilitated by the demise of RCA's cinema sound business unit, by the hand of GE, RCA's acquirer, and by its failure to protect the Photophone trademark.

The Westrex system (now renamed Photophone) is still in new production, with more than 100 systems currently in active service, world-wide. Some users, including Disney and Warners, have multiple systems. The RCA system is essentially defunct.

The Photophone (Westrex) system also has the capability of producing a DTS time-code track along with its native stereo variable-area tracks, or DTS time-code alone for use with 70mm and "special venue" prints.

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