Why should a black light lamp never be used with a cracked filter?

Using a black light lamp with a cracked filter is particularly dangerous because the integrity of the filter is compromised, allowing harmful ultraviolet (UV) light to escape. These UV rays can pose serious health risks to skin and eyes, causing potential harm such as skin burns or eye damage, including photokeratitis and long-term vision issues.

The function of the filter is to block certain wavelengths of light and only allow safe UV light that will interact appropriately with the penetrant. When the filter is cracked, not only does it fail to provide this necessary protection, but it also increases the risk of exposure to levels of UV radiation that could be harmful. It is essential to ensure that all equipment used in liquid penetrant testing is in proper working condition, particularly filters on UV lamps, to prioritize safety during the inspection process.