I disagree. Note that it wasn't a counter-argument, just added comment. Incidentally if you're interested, the historical "ao" didn't really refer to a specifi

I disagree. Note that it wasn't a counter-argument, just added comment. Incidentally if you're interested, the historical "ao" didn't really refer to a specific band of the the visible light spectrum as you suggest, it could mean any pale or ill-defined color, with "red" being used for any strong vivid color. Per wikipedia, anyway.