Violet is the color at the end of the visible spectrum of light between blue and the invisible ultraviolet. Violet color has a dominant wavelength of approximately 380-450 nanometers. Light with a shorter wavelength than violet but longer than X-rays and gamma rays is called ultraviolet. In the color wheel historically used by painters, it is located between blue and purple. On the screens of computer monitors and television sets, a color which looks similar to violet is made, with the RGB color model, by mixing red and blue light, with the blue twice as bright as the red. This is not true violet, since it is composed of multiple longer wavelengths rather than a single wavelength shorter than that of blue light.