At which stage of LPT is the developer applied?

The developer is applied after the penetrant has been removed from the surface of the test object. This step is crucial because it allows the developer to draw out any penetrant that may be trapped in defects. By using the developer, which is often a dry powder or a liquid, any penetrant that has infiltrated cracks or discontinuities can be re-triggered, allowing it to migrate to the surface where it can be more easily seen during the inspection process.

This stage is essential because it enhances the visibility of indications, making it easier for inspectors to detect and evaluate discontinuities that may be present in the material. The proper application of the developer plays a significant role in the overall success of the Liquid Penetrant Testing process, as it directly impacts the quality and clarity of the results obtained.