An expression for the maximum increase in signal to noise ratio obtainable with a pulsed hollow cathode lamp as primary source for atomic fluorescence measurements is derived under certain assumptions. Experience with copper and calcium hollow cathode lamps showed that by using these lamps in the pulsed mode in conjunction with a gated detector, the increase in signal to noise ratios obtained are less than a factor of 5, due to self-absorption broadening of the primary source emission lines.