Interpretation of Electron Micrographs Prepared by the Plastic Replica Process

Abstract

IN early work on the electron microscopic study of surfaces by the plastic replica process it was tacitly assumed that the upper surface of the replica, that is, the surface remote from that being examined, is substantially flat (fig. 1a). It has been suspected for some time that this is not so, and the matter has been discussed in a recent paper by Deacon et al.¹ ; but they have made no direct experimental test. Thus, it might be expected that a normal (unshadowed) replica micrograph would be the result of a superposition of the structure of the surface which had been in contact with the surface to be examined, and that of the upper surface of the replica. If the replica has the shape shown in Fig. 1b, artefacts will be introduced by the contour of the upper surface at the places indicated by dotted lines. A micrograph showing just this effect is reproduced in Fig. 2.