When should examination of the part begin?

• A. Soon after the developer is applied and continue periodically for the full development dwell time to observe the initial appearance and growth of an indication
• B. After drying
• C. Before applying
• D. During cleaning

Answer: (A)

In liquid penetrant inspection, you start looking as soon as the developer is applied and continue observing throughout the entire development dwell time. The developer draws penetrant out of any defects, creating visible or fluorescent indications that appear and change as the penetrant emerges at the surface. By beginning the examination early and monitoring during the full dwell period, you can detect the initial appearance and track the growth of indications, reducing the chance of missing small or developing flaws. Waiting until after drying, before applying, or during cleaning would either miss early indications or risk altering the indications, so examining during the development phase is the correct approach.