The frequencies of light that are visible to humans range from about 400 trillion to 790 trillion Hz. As you already know, when a sound rings at twice the frequency of another sound, we perceive them as being an octave apart. Something similar does not currently appear to be possible with light. If humans had evolved to see a wider spectrum of light and were able to see a color that was twice the frequency of another color, would they perceive them as being an "octave" apart,
i'd have to assume so