<P> Because of this, and because the primaries in color printing systems generally are not pure themselves, the colors reproduced are never perfectly saturated spectral colors, and so spectral colors cannot be matched exactly . However, natural scenes rarely contain fully saturated colors, thus such scenes can usually be approximated well by these systems . The range of colors that can be reproduced with a given color reproduction system is called the gamut . The CIE chromaticity diagram can be used to describe the gamut . </P> <P> Another problem with color reproduction systems is connected with the acquisition devices, like cameras or scanners . The characteristics of the color sensors in the devices are often very far from the characteristics of the receptors in the human eye . In effect, acquisition of colors can be relatively poor if they have special, often very "jagged", spectra caused for example by unusual lighting of the photographed scene . A color reproduction system "tuned" to a human with normal color vision may give very inaccurate results for other observers . </P> <P> The different color response of different devices can be problematic if not properly managed . For color information stored and transferred in digital form, color management techniques, such as those based on ICC profiles, can help to avoid distortions of the reproduced colors . Color management does not circumvent the gamut limitations of particular output devices, but can assist in finding good mapping of input colors into the gamut that can be reproduced . </P> <P> Additive color is light created by mixing together light of two or more different colors . Red, green, and blue are the additive primary colors normally used in additive color systems such as projectors and computer terminals . </P>

List the approximate wavelength (nm) for each color of the rainbow