An exposure system for electrophotographic apparatus having an aperture plate for masking one or more laser beams. The plate contains one or more apertures which have irregular edges to form a gaussian light distribution for the light beams passing through the apertures. A saw-toothed edge is used with a predetermined amplitude ratio to predictably attenuate the light at the edges which correspond to the process or in-track direction in the exposed image. The gaussian distribution is more tolerable of spacing changes in scan lines and improves the continuity of process direction lines in the finished image.