Phonovision
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 process involved taking the impulses from a mechanical Nipkow disk 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 lowering the frame rate to only 12 frames per second. Nevertheless, the results held some promise, and in the restored versions made from the original discs in the 1990's by the Scottish recording engineer 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 with mechanical resonance caused a 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.