In Liquid Penetrant Testing, what is the main purpose of a developer?

In Liquid Penetrant Testing, the main purpose of a developer is to absorb excess penetrant from the surface of the test item. This action allows any penetrant that has seeped into surface discontinuities—such as cracks or voids—to be effectively drawn out, enhancing the visibility of the indications (i.e., the flaws detected). The developer acts like a blotting agent, creating a contrasting background that makes the penetrant indications stand out more clearly for inspection.

While enhancing brightness of the penetrant (the first option) may seem relevant, the primary function of the developer is not to enhance brightness but to facilitate the visibility of flaws by managing penetrant residue. The options related to washing away indications and creating barriers are unrelated to the developer's role and instead reflect processes that do not align with the primary objectives of Liquid Penetrant Testing. Thus, understanding the developer's role is critical for effective testing and accurate flaw detection.