3 Analogies between color bands in the spectrum and tone intervals in scales

Athanasius Kircher had not only created symbolic classifications; in 1650, he also allocated colors to tone intervals. The color scale Kircher selected for his work was the system that had been newly developed by Franciscus Aguilonius in 1613, which was based on the three primary colors yellow – red – blue framed with white and black (following the Aristotelian tradition) and thus sorted according to brightness. Kircher then placed the color green, which had no collocation in this system, between the red and blue, correlated it with the octave, and allocated consonances to white and dissonances to black.

Isaac Newton started experimenting with prisms in 1666 and in 1671 divided the spectrum of sunlight into five colors: red – yellow – green – blue – purple. (In 1672, he even briefly considered a division of the spectrum into eleven parts.) In order to reach a more elegant and balanced distribution of the proportions of these five colors, in 1672 he introduced two intermediate colors and thus obtained red – orange – yellow – green – blue – indigo – violet. On the basis of this subdivision he postulated a similarity to the tonal system, given that the seven steps of his color scale partition the spectrum in the same way in which the seven notes are arranged on a musical scale. He then concluded that there could be a harmony of colors that was analogous to the harmony of musical notes. In 1704, he therefore arranged the seven colors in circular form and compared the color bands to the intervals within a Dorian scale. Committed as he was to the Greek ideal of a cosmic harmony, Newton also produced a comparison to the seven planets in accordance with the idea of a unity of nature. He published this analogical model in Opticks (1704) and it was later incorporated by succeeding color-tone theorists. Whereas the theories propounded up to then had only referred to tone intervals, it was in Newton’s publication that a comparison to a musical scale was made for the first time in history. From there it was only a small step to reduce the tone intervals within a scale to individual tones and the bands of color to individual colors, as came about at the beginning of the eighteenth century.

In addition, Newton’s model dispensed with Aristotle’s ordering of the colors between black and white and thus overrode numerous preceding theories of color while giving his own analogical color-tone model a physical foundation.