Experiments are described for investigating the interpretation of polystyrene‐silica surface replicas. It is demonstrated on a polished and etched stainless steel 18–8 specimen that the light microscope and electron microscope pictures are strikingly similar with corresponding regions easily recognized. The great value of stereo‐pictures in determining relative surface elevations is demonstrated with a comparison of the topography as shown by the light microscope using oblique illumination. The question of resolution is discussed and a method of quantitatively determining the practical limiting resolution of replicas is described. A shape limitation factor, &agr;, is defined and evaluated for both silica and Formvar replicas. With &agr; = 1 being perfect reproduction, the values obtained were &agr;∼1.3 for silica and &agr;∼3.8 for Formvar. The value &agr;∼3.8 is valid only for the surface employed in its determination while the value of &agr;∼1.3 is realized on any surface to which the polystyrene‐silica method can be applied.