Modern methods of photometric and colorimetric measurements are increasingly moving towards use of spectral concentration of a photometric value to determine both integral effective values, and to measure colorimetric values of self-luminous and non-self-luminous radiation sources applied in lighting installations and lighting devices. This is linked to decreasing use of incandescent lamps and to the expansion of energy efficient modern radiation sources in illumination technology. This article is dedicated to the problem of spectral measurements of optical radiation in a wide spectrum interval.