Louis Bertrand Castel
Jesuit monk Louis Bertrand Castel is a pioneer of the color organ, having created his clavecin oculaire in 1734. Castel considered himself a philosopher, though he was well-known as a mathematician. He penned two essays, the first in 1725, the second a decade later, regarding the creation of a "harpsichord for eyes." Castel had studied the mid-seventeenth-century magic-lantern designs of German Jesuit scholar Athanasius Kircher and wrote about transposing the pleasures of music from the ears to the eyes. In doing so, he also made a very early case for the development of visual music as an intermixing of the other arts, asserting, "The modification of light gives us colours, and that of sound Tones: the mixture of colours makes painting, that of tones Music." Castel's musical keyboard spanned five octaves: "When a key was depressed, a colored strip of paper or silk would appear above a black horizontal screen to the rear. The first octave represented the pure hues, the next the same hues 'one degree lighter and the fifth octave the highest values.'"
Castel's investigations into playing color begat a host of similar projects.
In his remarkable history of color instruments, Jorg Jewanski notes both the German doctor and naturalist Johann Gottlob Krueger's Farbeclavecymbel of 1743 as well as a hand-cranked musique oculaire--a phantasmagoria machine that projected ghostlike forms onto smoke--by Edme-Gilles Guyot in 1770
L'Optique des coleurs, 1740