An experimental study--involving measurements with an optical microscope, a profilometer, and a scanning electron microscope--for determination of the surface profile of x-ray tube anodes is presented. The islands on the "mud-flatting" surface are separated by approximately 8 microm deep cracks. The surface roughness on the island is typically below 1 microm, and the area ratio of cracks to the total surface is higher on the more extensively used regions (anode aging). A simple model was proposed to calculate the spectrum modification introduced by the rough surface. Loss of x-ray intensity of 4% was predicted using the roughest surface at a small emission angle.