Total luminous flux emitted by a high pressure mercury vapor lamp with phosphor is measuredand, compared with that of a standard incandescent lamp. The comparison is made with a photocell combined with glass filters. The spectral sensitivity of the photocell, the spectral reflectance of the sphere paint and the spectral energy distribution of an HPMV lamp with phosphor are measured and a correction factor is decided from the results of these measurements. The errors included in the measurements are analysed and the propagation of these errors to the correction factor is evaluated. As a result, it is concluded that the total luminous flux is measured with an accuracy of about ±2%.
