In General Printing Terms by Inkjet Insight

In color, a term descriptive of the relation between the light that is absorbed by a surface and the total light striking the surface. The perception of color is possible because different atoms absorb only certain wavelengths of light, and reflect light back in the opposite wavelengths. So, a substance that is perceived as red absorbs light in the green andblue wavelengths and reflectsred back to the viewer. Also called absorbtance.