Spectral uncertainties in photometry: new measuring methods and calculations

The new measuring methods and expressions for calculation of photometric uncertainties, related to uncertainties in the measurement of spectral characteristics of sources and photometers, are discussed. These expressions are different from those that the International Commission on Illumination (CIE) recommends. The results show that the real values of photometric uncertainties can essentially exceed those obtained by using methods recommended by the CIE, particularly for measurement of quasimonochromatic sources, such as LEDs, with the help of continuous spectrum sources.