The aim of this paper is to present the colorimetric and photometric results for a pulsed power supply operated high pressure sodium (HPS) lamp. Especially, we are interested in controlling the spectral response radiation of the yellow D line. This sodium D line is composed of two spectral components, one at 589.6 nm and the other at 589.0 nm. The pulsed power supply is a driver for the HPS lamp based on the application of a low frequency (50 Hz) square current waveform through the lamp with one or more pulses on each half cycle. A description is given of the physical modeling of the arc’s behaviour. Experimental results obtained from our laboratory power supply for a 400 W HPS lamp supplied at 50 Hz and simulations are shown.