Photometric errors with compact fluorescent sources

The author reports the extent of photometric errors observed when different compact fluorescent sources for retrofit are compared with the incandescent sources they are to replace. When the photometric measurements are collected under sources with different spectral composition, errors can occur if the photometer relative spectral responsivity does not exactly match the spectral luminous efficiency of the human eye. Calibration procedures developed to address this problem are described, and the photometric errors observed for four different units of the same model illuminance photometer used to measure different compact fluorescent and incandescent sources are reported