Have a look at a book published in 1930 by the composer Henry Cowell
New Musical Resources. He is imagining a future where composers can realise music directly without performers.
Conlon Nancarrow realised part of Cowell's program by writing piano music note by note with a player roll punch. He was pushing the medium and the resulting compositions are very hard if not impossible for a human pianist to play.
Daphne Oram used a more analogue system of photocells, blank cinema film and black ink to 'draw' music directly - her system specified the amplitude, frequency and harmonic complexity of sounds through time.
RO-BOW is an art work, but it strikes me as sort of like a deliberate use of black and white film in a pin hole camera by a photographer. Quaint, interesting, thought provoking, but quite retro when you can record images in full colour with enormous resolution. This paragraph isn't quite capturing what I'm trying to say so I'll have another think...