Various color etching techniques are by now well introduced and complement the standard preparations in many metallographic laboratories or, in the case of some material groups, even replace them. However, the interpretation of the thus obtained micrographs requires a certain experience. In order to recognize and utilize the benefits of color etching, the preparation as well as the evaluation should be practiced under supervision. Misinterpretations can thus be avoided. On the one hand, color etchings according to Klemm can help to better recognize carbide precipitations on the grain boundaries as well as segregations in unalloyed and low alloyed steels, cast iron, and in tool and quenched and tempered steels (Klemm I). On the other hand, these etchings (Klemm II and Klemm III) are also very well suited for copper alloys and solderings. They serve to reveal various solid solution types, separations (segregations), diffusion zones, and fine precipitations.