What happens when acid materials are not completely removed before applying fluorescent penetrant?

When acid materials are not completely removed prior to applying fluorescent penetrant, the fluorescence of the penetrant decreases. This is due to the fact that residual acids can interfere with the chemical properties of the penetrant dye. The presence of acids can inhibit the ability of the penetrant to fluoresce effectively under ultraviolet light. This means that even if there are defects present, the indication of those defects may be diminished or not visible at all due to the interference from the contaminants.

Additionally, proper cleaning before testing is crucial because it ensures that the penetrant can adequately fill surface defects. If the penetrant's fluorescence is compromised, the overall efficacy of the inspection process suffers, potentially leading to undetected flaws in the material being examined. Ensuring a clean surface maximizes the visibility of any indications and enhances the reliability of the test results.