Optophony

Optophony

You record with light instead of a pen — that is the core of optophony. The idea: visual shapes that you paint onto film or generate with light sources are read by a photoelectric cell and directly translated into audio signals. No detour via notation, no classic synthesis hardware. The light itself becomes the sound carrier.

In the 1920s, artists like Oskar Fischinger and other avant-garde figures experimented with this technique. They drew and scribbled on filmstrips, ran geometric shapes over light discs — and sound emerged from the projector. No musicians, no instrument miking. Pure light-to-sound conversion. Fischinger used this for abstract films where the visual composition and the sound composition came from one source — because they were literally one and the same. Sound generation was visually controllable, directly on set or in the editing process.

Practically, it works like this: An optoelectronic scanning device (originally a photocell, later more complex sensors) follows the brightness values on the filmstrip or a projected light source. High brightness = high frequency, certain shapes = different timbres. So you paint a sine wave, and it becomes audible as a sine tone. You draw a sawtooth waveform, and you hear a sawtooth sound. It is direct visual synthesis — a precursor to modern optical synthesis methods and sample-based sound design approaches.

Today, optophony is less in productive use, but the concept lives on in digital processes: spectrograms, wavelets, frequency-based visualization. Some experimental filmmakers and sound artists consciously resort to the technique to re-experience the close coupling between image and sound — and to show that sound doesn't have to be composed independently but can emerge from visuality. It is a reminder that sound and image are related on a physical level and that they can be conceived together synaesthetically.