Look closely at a rainbow, and you’ll spot red, orange, yellow, green, blue, and violet, but not purple. That’s because every color in a rainbow corresponds to a single wavelength of light.

The human eye does not actually see purple ... by a wavelength of light, and the strength of the signal from each cone (and type of cone). The brain then determines what color you are looking ...

MIAMI-DADE COUNTY, Fla. – Residents in some South Florida neighborhoods have noticed that their local street lights are turning purple. The Florida Department of Transportation is replacing more ...