Page 6 - HAIR COLOUR

All wavelengths are registered on a spectrum called the Electromagnetic
Spectrum. (Fig 3.)

You will notice from this linear version of the electromagnetic spectrum,
that it actually contains a visible spectrum and an invisible spectrum.
The visible spectrum contains wavelengths from 400nm to 700nm.

The invisible spectrum contains infra red and radio wavelengths between
700nm to 1metre or greater at the cool end of the electromagnetic
spectrum, and ultra violet rays, x-rays and gamma rays from 400nm to
th
100 of a nanometre at the hot end of the electromagnetic spectrum.

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