Optics and radiometric magnitudes: are their connections clear?

The relations between radiometric magnitudes and quantities associated to optical properties of materials (processes of reflection, transmission and emission of radiant flux by or through material media) have been analyzed. By studying some particular examples, we illustrate the dependence of optical properties of materials on the radiometric magnitude chosen and it is shown that quantities obtained from a radiometric point of view differ mathematically and physically from the corresponding Optics expressions.