Illuminants

 Electro magnetic radiation in the wavelength range of 380 nm to 730 nm is seen as light by our eyes. Low wavelengths show as blue light. Then the spectrum continues from green, yellow, orange to red.
UV radiation is located in the range underneath 380 nm; the range above 730 nm is called infrared radiation.

The visual impression of a colored body changes by the composition of the incoming light.