There is a twelve-note scale in music but the "black" notes are considered less important than the "white" ones. Similarly, with spectral colours there´s an uneven distribution, but by happenstance the visible electromagnetic spectrum covers almost exactly one octave. It´s therefore possible to apply the same principle to spectral colours, logarithmically arranged like notes. One of the things you get as a result is an extra hue between indigo and violet. This is how it goes (each wavelength is, logarithmically speaking, the middle of the range of that colour):The "white" hues are maroon, red, orange, lime (roughly, i´m not au fait with the technical terms here), green-blue, indigo and violet. The "black" hues are crimson, "blood orange", green, blue and indigo-violet.Alternatively, these can be seen as a sequence of colours from deep red to violet. I can see several advantages to this: * It unifies the musical and colour spectra, creating artificial synaesthesia.* It gets rid of the spurious "yellow", which is really just orangey-green pretending to be a colour* It´s fairer to the violet end of the spectrum, which right now is a huge expanse of colour with just one name.* It compensates for the poor colour perception at the shorter wavelengths by providing divisions between those colours and making them more noticeable, like the Inuit "snow" myth.* It provides a name for the colour between indigo and violet.* It involves the number twelve.-- nineteenthly, Dec 08 2008 You are guaranteed to make persons with synaesthesia completely bonkers. Their main complaint re color is that people put the wrong color with their letters/numbers/sounds/days of the week/etc...-- bookwench, Dec 10 2008 random, halfbakery