We analyze the effects of m 0 tip states in scanning tunneling microscopy (STM). If near the Fermi level, an m 0 tip state dominates, images with large but inverted atomic corrugation are expected. This provides an explanation of the STM images with inverted corrugations, and the sudden reversal of the STM corrugation from inverted to noninverted. An analysis of the effects of various combinations of m 0 and m=0, d-type tip states is presented. We show that in most cases, a stable and large corrugation enhancement, either positive or negative, is expected, with predicted values in agreement with experimental observations. © 1992 The American Physical Society.