Editing Phonautograph (section)

== Playback ==
By mid-April 1877, [[Charles Cros]] had realized that a phonautogram could be converted back into sound by [[photoengraving]] the tracing into a metal surface to create a playable groove, then using a [[stylus]] and [[diaphragm (acoustics)|diaphragm]] similar to those of the phonautograph to reverse the recording process and recreate the sound. Before he was able to put his ideas into practice, the announcement of [[Thomas Edison]]'s [[phonograph]], which recorded sound waves by indenting them into a sheet of tinfoil from which they could be played back immediately, temporarily relegated Cros's less direct method to obscurity.<ref name="Berliner" />

Ten years later, the early experiments of Emile Berliner, the creator of the disc [[Gramophone]], employed a recording machine that was in essence a disc form of the phonautograph. It traced a clear sound-modulated spiral line through a thin black coating on a glass disc. The [[photoengraving]] method first proposed by Cros was then used to produce a metal disc with a playable groove. Arguably, these circa 1887 experiments by Berliner were the first known reproductions of sound from phonautograph recordings.<ref name="Berliner">Berliner, E: "The Gramophone: Etching the Human Voice", ''Journal of the Franklin Institute'', June 1888 125(6):425–447. Berliner, who scrupulously acknowledges the work of Scott and Cros in this paper, uses the word "phonautogram" (see pages 437 and 438) to describe his own recordings prior to their processing into playable form by photoengraving or direct etching.</ref>

However, as far as is known, no attempt was ever made to use this method to play any of the surviving early phonautograms made by Scott de Martinville. Possibly this was because the few images of them generally available in books and periodicals were of unpromising short bursts of sound, of fragmentary areas of longer recordings, or simply too crude and indistinct to encourage such an experiment.<ref>Morton, D., ''Sound Recording: The Life Story of a Technology'', JHU Press, 2006 indicates (see page 3) that this could be the case even when photochemical processes were no longer the only option and optimized results were possible: in 2000, a planned experiment to recover sounds from phonautograms by means of scanning and digital processing was abandoned because there was "little to try to recover" in the specimens at hand.</ref>

Nearly 150 years after they had been recorded, promising specimens of Scott de Martinville's phonautograms, stored among his papers in France's patent office and at the Académie des Sciences, were located by American audio historians. High-quality images of them were obtained. In 2008, the team played back the recordings as sound for the first time. Modern computer-based image processing methods were used to accomplish the playback. The first results were obtained by using a specialized system developed for optically playing recordings on more conventional media which were too fragile or damaged to be played by traditional means. Later, generally available image-editing and image-to-sound conversion software, requiring only a high-quality scan of the phonautogram and an ordinary personal computer, were found to be sufficient for this application.<ref>{{Citation |title=FirstSounds.org |url=http://www.firstsounds.org}}</ref><ref name="NYT2008">{{Cite news |last=Rosen |first=Jody |date=March 27, 2008 |title=Researchers Play Tune Recorded Before Edison|work=[[The New York Times]] |url=https://www.nytimes.com/2008/03/27/arts/27soun.html}}</ref>

For First Sounds' March 2008 release of "Au Clair de la Lune", its engineers wrote software to improve the stability of the sound. It did the same with a May 17, 1860 recording of "Gamme de la Voix" which First Sounds presented at the Audie Engineering Society's convention in late 2008.<ref>{{cite web |url=https://firstsounds.org/sounds/approach.php |title=Retrieving Sound from Soot—Our Evolving Approaches|publisher=First Sounds|access-date=April 20, 2023|archive-date=March 7, 2023|archive-url=https://web.archive.org/web/20230307231619/https://firstsounds.org/sounds/approach.php}}</ref>