Phonautograph is a film exploring the human compulsion to articulate and visualize sound. Its narrative traces the history of capturing, preserving and reproducing acoustic signals, presenting material recorded on the early devices of Édouard-Léon Scott de Martinville. Patented in 1857, the Phonautograph was an invention that transcribed sonic frequencies onto paper, from where they could be analyzed and studied graphically. For a long time people believed that the amount of information it “stored” was insufficient to recreate the actual sound, but in 2008 American sound engineers found a way to do just this. Through optically scanning the old phonautograms and playing them back at the correct speed, the voice of a man believed to be Scott de Martinville himself, could once again be heard. The words were recognized as lines from the French folk song Au Claire de la Lune, recorded in 1860, making it the oldest known recording of the human voice.