The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 380 to 750 nanometers. In terms of frequency, this corresponds to a band in the vicinity of 430–770 THz.
The spectrum does not, however, contain all the colors that the human eyes and brain can distinguish. Unsaturated colors such as pink, or purple variations such as lavender, are absent because they can be made only by a mix of multiple wavelengths. Colors containing only one wavelength are also called pure colors or spectral colors.
The visible spectrum is important in the visual arts because it is the part of the electromagnetic radiation spectrum that human eyes can see, and thus what artists use when designing visible artworks.
The idea of the visible spectrum was put forward by Isaac Newton in his treatise Opticks, which he published in 1704. In this work he showed that sunlight could be decomposed into a spectrum of colors by means of a prism. He also showed that the individual colors making up this spectrum could be recombined to form white light, which is what we see when we look at an object illuminated by sunlight or by artificial light.
