Ranges of electromagnetic radiation.
The spectrum of visible radiation covers the narrow range from 380 to 780nm.
Adjacent to the light spectrum visible to the human eye is the short-wave UV range (ultraviolet radiation) on the one side, and the long-wave IR range (infrared radiation) on the other. These contrasting peripheral areas are partly visible to other organisms.
Relative spectral distribution Se (λ) of low pressure sodium vapor discharge. The emitted line spectrum is close to the maximum sensitivity of the eye.
Relative spectral distribution Se (λ) of high pressure mercury vapor discharge.
In line and band spectra, gaps exist that separate individual radiation areas from each other.