Color in Light
How we measure color in light? A part of the Electromagnetic Spectrum called Visible Light is measured in nanometers, nm. This information is useful when understanding the color rendering ability and color bias of various light sources when compared to daylight.
The primary colors in light; red + blue-violet + green combine to make white light. The shadows in pure color light make the complimentary colors, found opposite on the color wheel, magenta, turquoise, yellow.
Tri colors forming white light.
This photo illustrates how complimentary shadows can be seen in color when a three primary light colors from white light, shining from different angles. Notice the light on her face shows natural color illuminated with white light; however, the shadows are bright Turquoise, Magenta, and Yellow.
The difficulty in performing this experiment is finding pure primary light sources, in the old days we used dicro PAR lamps, or theatrical filters, today we can use Monocrhomatic or tunable LED sources.
Color Vision in Insects and animals
Animals have vision that differs from humans, bees and butterflies see colors we cannot see, more Ultra Violet wavelengths, guiding them to the patterns in flowers. Dogs and cats mostly see."... greys and some blues and yellows." 
Electromagnetic Spectrum & Visible Light
Visible light is only part of the Electromagnetic Spectrum surrounding us, X rays;, Ultra Violet Light, UV, Visible Light, Infa Red Light, Microwaves, Radio Waves, and Long waves.
390 to 700 Nanometers, nm, describes the wavelengths visible to the human eye.
Flower Insect Vision by Tess Watson