Penetrant testing can be used on all solid materials. The method can be used to identify e.g. surface cracks, overlaps or pores in one step. In this course, the individual procedural steps and inspection, measuring and test equipment systems will be discussed. System and procedural checks will be dealt with at depth. Bodies of standards such as EN ISO 3452-1 corresponding to the various industrial sectors and also lists of flaws and evaluation criteria will be presented.