Source color, surface color
Color and visual appearance. Transparent, translucent, opaque

The historical experiments that led to the formation of modern colorimetric science were based on the quantitative estimation of visual perceptions based essentially on direct observation of primary light sources. The influence of the environment and the visual angle at which light enters the eye were not recognized and considered until well after the beginnings of colorimetry. It's for these reasons that the distinction between surface color and source color is maintained today. This distinction remains important today, as many visual effects, notably angular variations in reflection or transmission functions, need to be studied and understood through simulation and spectrophotometric, and more precisely goniospectrophotometric, measurements. For all radiometric and photometric quantities, their definitions and units, please refer to