What is the function of a developer in liquid penetrant testing?

The primary function of a developer in liquid penetrant testing is to enhance the visibility of penetrant indications. After the penetrant has been applied and allowed to seep into any surface-breaking defects, the developer is applied to the test surface. This substance works by drawing the penetrant out from the defects and spreading it on the surface, which increases the contrast between the defect indication and the background. As a result, it makes the indications much more visible during inspection, enabling the inspector to assess the quality and integrity of the material being tested effectively.

While cleaning the surface after testing and providing a contrasting background are important aspects of the testing process, they do not directly describe the primary role of the developer. The developer is specifically designed to facilitate the detection of defects by enhancing the visibility of the penetrant-filled indications.