In what type of area should the actual inspection using a fluorescent penetrant be performed?

The correct choice is a darkened area under a black light because fluorescent penetrant inspection relies on the ability to detect fluorescent dye in the penetrant after it has been applied to the surface of the material being inspected. The black light emits ultraviolet (UV) light, which causes the fluorescent penetrant to glow brightly, making it easier to see any defects that may be present.

Performing the inspection in a darkened area enhances the visibility of the fluorescent indications, allowing for a more accurate and thorough inspection process. This contrast is vital because it minimizes interference from ambient light, which can obscure subtle indications of defects.

Well-lit areas with natural light or fluorescent lighting can create competing light sources that diminish the visibility of the glowing penetrant, making it challenging to identify flaws. Outdoor areas during daylight can also suffer from similar issues with ambient light interference. Thus, the best practice is to conduct the inspection in a controlled environment where the use of a black light can maximize contrast and visibility.