In liquid penetrant testing, which function is NOT performed by the developer?

In liquid penetrant testing, which function is NOT performed by the developer?

• A. Provide a contrasting background to reveal the indications
• B. Help to distribute the penetrant evenly
• C. Add fluorescence to penetrants
• D. Aid in visualizing indications under correct lighting

Answer: (C)

In liquid penetrant testing, the developer’s role is to provide a contrasting background and to draw penetrant out of surface-breaking flaws so the indications can be seen under proper lighting. It creates the white (or light) field against which any penetrant that has entered a flaw can be pulled to the surface, forming a visible indication. The fluorescence (for fluorescent penetrants) or the color (for visible penetrants) comes from the penetrant itself, not the developer, so the developer does not add fluorescence to penetrants. The distribution of penetrant across the surface is achieved during the initial application and dwell time of the penetrant, not by the developer. Finally, with the appropriate lighting—UV for fluorescent penetrants or white/appropriate illumination for visible penetrants—the indications stand out against the developer’s background.

In liquid penetrant testing, the developer’s role is to provide a contrasting background and to draw penetrant out of surface-breaking flaws so the indications can be seen under proper lighting. It creates the white (or light) field against which any penetrant that has entered a flaw can be pulled to the surface, forming a visible indication. The fluorescence (for fluorescent penetrants) or the color (for visible penetrants) comes from the penetrant itself, not the developer, so the developer does not add fluorescence to penetrants. The distribution of penetrant across the surface is achieved during the initial application and dwell time of the penetrant, not by the developer. Finally, with the appropriate lighting—UV for fluorescent penetrants or white/appropriate illumination for visible penetrants—the indications stand out against the developer’s background.