Phonovision

From Citizendium, the Citizens' Compendium
Jump to: navigation, search
This article is developed but not approved.
Main Article
Talk
Related Articles  [?]
Bibliography  [?]
External Links  [?]
Citable Version  [?]
 
This editable Main Article is under development and not meant to be cited; by editing it you can help to improve it towards a future approved, citable version. These unapproved articles are subject to a disclaimer.
Frame stills from the "Miss Pounsford" Phonovision disc of 1928; Image © 1985 by Don McLean, used with permission from his tvdawn.com webpages.

Phonovision, an experimental process for recording a television signal on phonograph records, was developed in the late 1920's in England by British television pioneer John Logie Baird. The goal of Baird's process was not merely to record video, but to do so synchronously. Baird hoped to design a system which would permit playback from an inexpensive home device, which he dubbed a 'Phonovisor'. Had it been perfected, it would have been the first home-video playback system in the world, but Baird abandoned his research after encountering problems due to the limitations with the equipment available to him at the time. Nevertheless, the Phonovision recordings are the eariest known recordings of a television signal ever made, and as such they offer an extraordinary window into the early development of television.

The process involved taking the impulses from a mechanical Nipkow disk, acting as television camera, and connecting them via a mechanical linkage to the cutting stylus of a record-mastering turntable. Baird had to make a number of compromises to get the process to work, among them using a picture rate of only 4 frames per second. The results were considered a failure at the time, and Baird moved on, leaving behind several discs in the hands of museums and favored company members. Nevertheless, the results held some promise, and in the restored versions made from the original discs in the 1980's by the Scottish image processing expert Donald McLean, some of the images are quite vivid and haunting. These images, alas, were never seen in such quality by the original Baird engineers, as problems such as mechanical resonance caused distortion and misalignment of the lines in the signal; one engineer compared the image of a human face from a phonovision recording to a "head of cabbage."

The earliest surviving phonovision disc depicts one of the "Stookie Bill" dummy heads which Baird employed for tests, and was recorded on September 20, 1927. The earliest recording of a human face is of Wally Fowlkes, and was made on January 10, 1928. Later that year, on March 28, a recording of "Miss Pounsford" was made which is, in many ways, the best of the experimental discs.

Despite its technical problems, Phonovision remains the very earliest means ever invented of recording a television signal. In a sense, it can be seen as the progenitor of other, later, disc-based systems including RCA's capacitance-based discs, known as SelectaVision. The fully restored images may be seen on the CD-ROM documentary, The Dawn of Television Remembered, produced by Mr. McLean.