Objects contain pigments that selectively absorb a wavelength of light, and our eyes only observe a very small range of these wavelengths. Scholars apply these two facts to three different activities. They identify the pigment in an unknown sample based on the color participants observe when two different lights illuminate it. Then, they determine the color of a shirt given the pigments it contains and the light under which they view it. Finally, they inform a printer which pigments to use to have something appear with a variety of different colors.