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Color spectrum

When we look at object, the object is seen, when the light coming from the object reaches the human eye. This light causes the color perception.

A property of light is wavelength. The wavelength range, which is visible to the human, is from 380 nm to 780 nm. Each wavelength is seen as different color, as shown in Figure1.

Figure 1. This spread of light into the colors can be seen in a rainbow.

The wavelength spectrum of color, or color spectrum is the intensity distribution of light according to the wavelength. In Figure 2, the color spectrum of a birch tree can be seen.

Figure 2. The light coming from a natural object include all the wavelengths. The perceived color of the object depends on relative amount of each color in the spectrum.