If dye penetrant inspection indications are not sharp and clear, the most probable cause is that the part

• A. was not thoroughly washed before the developer was applied
• B. the penetrant wasn't heated enough
• C. the part is not properly dried
• D. the surface is too rough

Answer: (A)

Dye penetrant inspection relies on a clean surface and a clear sequence so that the penetrant’s trace at a flaw stands out with sharp edges. If the surface isn’t thoroughly washed before the developer is applied, oils, grease, or other residues remain on the surface. Those films interfere with how the developer draws out the penetrant and how the background contrast forms, causing the indicated flaws to look smeared or blurred rather than crisp. Heating the penetrant, drying, or surface roughness can alter visibility or shape, but surface contamination from incomplete washing is the most likely reason for indistinct indications.