It’s simple improving of VT reliability in specific applications. Although this is classified as surface method, we can distinguish between scratch and crack. Sensitivity increases, it means better resolution with more susceptible condition. Only open-to-surface defects can be detected, good cleaning is necessary. We report just an indication; the real source stays uncertain (it is common feature of every method except VT). PT can be applied to smooth, clean surfaces. A productivity of PT lines is impressive: a batch of small object can be processed at once. Using fluorescent technique, the indication “shines” and is clearly visible. It’s the only method for e.g. chromium layer integrity investigation. A manual technique of cans (sprays) is very popular in the course of in-service inspections - detection of flaws and fatigue cracks.