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.

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.

Primary RCA (Photophone) licensees include:

*Walt Disney Productions
*RKO Radio Pictures (liquidated)
*Republic Pictures (liquidated)
*Warner Brothers

Secondary RCA licensees include:

*Revue Productions (later integrated into Universal Studios)
*Screen Gems (later integrated into Columbia Pictures)
*TCF-TV (later integrated into Twentieth Century-Fox)

Primary Western Electric (Westrex) licensees include:

*Columbia Pictures
*Samuel Goldwyn (liquidated)
*Metro-Goldwyn-Mayer
*Paramount Pictures
*Rank Organisation (liquidated)
*Selznick International (liquidated)
*Twentieth Century-Fox
*Universal Pictures

Secondary Western Electric licensees include:

*Robert L. Lippert (liquidated)
*Monogram Pictures (liquidated)
*(Fox) Movietone News (liquidated)
*Ryder Sound Services (liquidated)
*Technicolor Corporation
*Todd-AO Corporation

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.

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 (a wholly-owned subsidiary of Litton Industries since 1956, 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 Laboratories'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.

"Open" versions of Westrex's stereo variable-area exist as well.

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.

ee also

*Vitaphone
*Movietone
*Phonofilm
*Photokinema
*Sound film
*Sound-on-disc
*List of film formats

References

*Frayne, J and Wolfe, H, "Sound Recording", New York, Wiley & Sons (1949). Discusses, in the abstract, the components of what later became today's Photophone system, but the references are spread throughout this essential and definitive text.
*Coe, Brian, "The History of Movie Photography", Westfield, NJ, Eastview Editions (1981), ISBN 0-89860-067-7.
*Enticknap, Leo, "Moving Image Technology: From Zoetrope to Digital", London, Wallflower Press (2005), ISBN 1-904764-06-1.
*Gomery, Douglas, "The Coming of Sound", London & New York, Routledge (2005), ISBN 0-415-96901-8.