Human sight. Artwork of an eye and brain superimposed over a human head in profile with wavelengths of visible & invisible light. Certain wavelengths of light (coloured, at right) are visible to the human eye. Light is shown entering the eye (circle) and being processed by the brain (pale blue) behind. Visible light has a wavelength of 400-700nm and is a type of electromagnetic radiation. It consists of oscillating electric and magnetic fields propagating together as a radiated wave. The other waves shown are invisible to human sight and are from top: microwaves, far infrared, infrared, ultraviolet, X-rays and gamma rays.