Morphological features of Lichtenberg figures created by electrostatic separation discharges on the surfaces of electret samples have been studied by means of multifractal analysis. The monofractal ramification of surface positive-channel streamers has been confirmed and found to be dependent on actual experimental conditions. For the lower level of electret saturation used, the fractal dimension D approximate to 1.4 of the surface Lichtenberg channels has been obtained. Various registration features of electret and non-electret samples have been discussed and illustrated.