I've often wondered "How would you describe colour to a blind person" (obviously, someone who's been blind from birth). The best I've come up with is comparing

I've often wondered "How would you describe colour to a blind person" (obviously, someone who's been blind from birth). The best I've come up with is comparing it to sound - sharp and dull sounds relate to wavelength, as does colour; loud and soft sounds relate to brightness. Any better ideas out there? I admit it's a largely pointless exercise, one of many I have to amuse myself.