What type of lighting is most effective during a fluorescent penetrant inspection?

In fluorescent penetrant inspection, ultraviolet lighting is the most effective choice as it enhances the visibility of the fluorescent penetrant materials used to detect surface-breaking defects. During this process, the penetrant retains its fluorescent properties, generating a bright glow under UV light when it is present in cracks or other discontinuities.

The use of ultraviolet light causes the fluorescent penetrant to emit visible light, which makes it much easier to identify flaws against the surface of the inspected material. The specific wavelengths of UV light used in fluorescent testing are tailored to activate the fluorescent compounds in the penetrants, leading to a stark contrast between the defect and the surrounding material.

Other lighting types, such as incandescent, fluorescent, or halogen lighting, do not provide the same level of contrast or enhance the visibility of the fluorescent penetrant as effectively. They may illuminate the surface but will not activate the fluorescent response necessary for accurate inspection, making them less suitable for this type of testing. Therefore, ultraviolet lighting is critical for achieving reliable results in fluorescent penetrant inspections.