The article presents a method of evaluating irradiance, spectral irradiance, and spectral radiance, for purposes of determining risk groups of sources of light. The description of the method of measurement of radiance incorporates standard and alternative methods. Measurement methods were developed on the basis of general requirements and diagrams incorporated in the standard PN-EN 62471: 2010. The paper classifies risk groups of sources of light in terms of photobiological hazards and exposure limits when skin is at risk of being damaged by visible and infrared radiation. Threshold values of emissions for the continuous sources of radiation studied are presented. The article describes environmental conditions under which the measurements are to be taken, and requirements applicable to the process of light source aging. In addition, technical assumptions are presented, and the design of the test stand for measuring optical radiation parameters is described.