By definition, penetrant testing (PT) is the resurgence of a liquid (or a gas) from a discontinuity in which it had previously been introduced during a penetration operation. A logical extension of the visual examination, this method makes it possible to detect discontinuities opened to the surface of the controlled part in the form of colored or fluorescent indications, respectively observed against a white background or on a black background. PT comes in four phases, the first of which is...
