The influence of different photometric observers on luxmeter accuracy for LEDs and FLs lamps measurements

Age-dependent changes in human eye spectral sensitivity play an important role in contemporary lighting research. Nowadays lighting designing practices take into account the fact that an illuminance level perceived by a given observer depends also on his age. According to recommendations of the International Commission on Illumination CIE presented in the document 227:2017, users age should be taken into account in lighting design of public buildings. The natural consequence of this approach in designing should be the fact that the age of a user also should be considered when verification of lighting installation photometric parameters is performed. According to recommendations of latest CIE documents, verifications of illuminance levels are performed by luxmeters whose spectral sensitivity matches the CIE standard photometric observer V(λ) function. At present there is a lack of papers describing how the accuracy of illuminance measurements could be affected by the fact that with age there are changes in human eye spectral sensitivity and it differs from V(λ) function. To fill this gap we present in this article results showing how applying of different photometric observers influence the luxmeter accuracy. The calculations were performed for LED and FL light sources measured by class B and class C luxmeters. These results indicate that a luxmeter error f1 strongly depends on correlated color temperature of a lamp under measurement and spectral sensitivity of applied photometric observer