Etching experiments have been carried out with in order to check mathematical models developed for diffusion‐controlled dissolution at resist edges. Both electroless and chemical etchants were used, and their chemistry is briefly considered. An interesting method of controlling the electroless dissolution rate of by means of a diffusion‐controlled oxidation reaction is reported. The excellent agreement between calculated and measured etched profiles demonstrates the validity of the mathematical model. The influence of natural convection and of convection induced by gas evolution is reported, and the results are compared with theory.