File:Bell telephone magazine (1922) (14755998005).jpg

Identifier: bellvol25telephonemag00amerrich (find matches)
Title: Bell telephone magazine
Year: 1922 (1920s)
Authors: American Telephone and Telegraph Company American Telephone and Telegraph Company. Information Dept
Subjects: Telephone
Publisher: (New York, American Telephone and Telegraph Co., etc.)
Contributing Library: Prelinger Library
Digitizing Sponsor: Internet Archive

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ever listened to a singlespeaker. Another great stride toward soundpictures had been accomplished. During the previous year Wentehad been working on the recording ofsound upon film by the variable densitymethod. The 1912-13 recordings upon film had been by the variable areamethod. Those of 1919 were made bythe variable density method. The twomethods have been briefly summarizedas follows:In variable density recordings, themotion picture film is moved atright angles to a narrow slit, me-chanical or optical, through whichover Its whole length there fallsupon the film a light varying in In-tensity with the sound pressure tobe recorded. In variable area re-cording, there Is a like slit, but whatvaries with the sound pressure isthe length of the part of the slitthrough which a constant lightreaches the film. When completed,the variable density record viewedlengthwise looks like a ladder withrungs spaced according to the pitchand darkened according to theloudness of the recorded sound. The
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E. B. Craft (left) makiiig a sound picture for demonstration^ at the Vitapho)ie Studiosin the Manhattan Opera House in IQ26. He exhibited the first electricallv recorded sound picture in IQ22 1946 Twenty Years of Talking Movies 93 variable area record, viewed fromthe edge of the film, looks like ahedge with uneven trimming, hav-ing peaks and pits correspondingin height to the loudness and inspacing to the pitch of the sound-ded. recor( Upon first undertaking the variabledensity method, Wente consideredvarious devices which had been pro-posed. It appeared to him that themethod being used in that year, 1920,by Professor Rankine of England, forspeech transmission over a light beammight provide the most correct filmexposure. He made certain modifica-tions of the device and constructed aninstrument of similar type. The qual-ity of his recordings compared favor-ably with that of the commercialphonograph records, but that did notsatisfy Wente or Arnold. Wentefinally concluded that the method

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