Measuring methods to ensure quality therefore do not play a bigger role in the workshops, although there exist a broad scale of different methods, from visual control over simple testing methods (among other things water break test, wipe test, measurement of contact angle, test inks, tape test) to complex analysis methods (among others gravimetric test, particle counting, infrared spectroscopy, glow discharge spectroscopy, energy dispersive X-ray analysis, scanning electron microscopy and electrochemical methods). Nevertheless, there are only few methods, which can be applied directly in the line and which offer reproducible and comparable results. It was not until recently that bigger advancements in this area have been made