|
:''This article is for the sound-on-film technology. For the telecommunication device invented by Alexander Graham Bell and Charles Sumner Tainter, see 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 an optical sound, "variable-area" film exposure system, in which the modulated area (width) corresponded to the waveform of the audio signal. The three other major technologies were the Warner Brothers Vitaphone sound-on-disc system, as well as two "variable-density" sound-on-film systems, Lee De Forest's Phonofilm, and Fox-Case's Movietone. When Joseph P. Kennedy and other investors merged Film Booking Offices of America (FBO) with the Keith-Albee-Orpheum theater chain and Radio Corporation of America, the resulting movie studio RKO Radio Pictures used RCA Photophone as their primary sound system. In May 1929, RKO released ''Syncopation'', the first film made in RCA Photophone. == History and licensing == In the early years following World War I, Charles A. Hoxie working at General Electric (GE) developed a photographic film recorder, initially to record transoceanic wireless telegraphy signals. However this recorder was later adapted for recording speech and was used in 1921 to record speeches by President Coolidge and others which were broadcast over Station WGY (Schenectady). This recorder was called the ''Pallophotophone''. In 1925 GE started a program to develop commercial sound-on-film equipment based on Hoxie's work. Unlike the Phonofilm and Movietone systems in which the audio modulated the intensity of a recording lamp which exposed the soundtrack, thus creating a variable-density track, the GE system employed a fast-acting mirror galvanometer to create a variable-area soundtrack. A number of demonstrations of this system, now known as Photophone, were given in 1926 and 1927. The first public screenings with this system were of a sound version (music plus sound effects only) of the silent film Wings which was exhibited as a road-show in around a dozen specially equipped theatres during 1927.〔History of Sound Motion Pictures, E.W. Kellog, Journal of the SMPTE Vol 64 June 1955〕 In 1928 RCA Photophone Inc was created as a subsidiary of RCA (itself then a GE subsidiary) to commercially exploit the Photophone system. The RCA system continued to use the ''galvanometer'' until the 1970s, when it became technically obsolete. The Western Electric system continued to use the ''light valve'', and, under successor ownership, is still used to this day. For nearly half a century, motion picture sound systems were licensed, with two major licensors in North America, RCA and Western Electric (Northern Electric, in Canada), which licensed their principal sound element (original track negative) recording systems on a non-exclusive basis. In general, motion picture producers elected to license one or the other. In a few cases, where mergers had occurred, a producer might be licensed for both. For many years, it was customary to "brand" a film with its sound system, variously as "RCA Sound Recording", "Western Electric Recording", or similar brands, often including the corporate logo of the licensor (''Meatball'' for RCA; ''The Voice of Action'' for Western Electric; ''Li Westrex'' for the post-1956 divestiture of Western Electric under Litton Industries' ownership). Such branding ceased in about 1976, particularly after nearly all optical sound recording (for release prints) had been converted to Westrex's stereo variable-area system from RCA's and Westrex's mono systems, although there were a few examples of such branding thereafter (mainly Westrex.) Many years later, the Photophone trademark would be reused by the Western Electric/Westrex stereo variable-area system, after both the Western Electric and Westrex trademarks became unavailable due to corporate asset sales by the disintegrating Bell System, but the Western Electric/Westrex stereo variable-area system continued to be marketed by a successor, and it is still serviced and supported to this day, although it is no longer branded as Photophone. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「RCA Photophone」の詳細全文を読む スポンサード リンク
|