A good penetrant is typically characterized by which of the following properties?

A good penetrant is characterized mainly by its wetting ability. This property is crucial as it ensures that the penetrant can spread and adhere to the surface of the material being inspected. Wetting ability allows the penetrant to effectively enter any surface-breaking defects such as cracks or voids, enhancing the reliability of the inspection process. If a penetrant does not wet the surface properly, it may fail to reveal critical flaws, undermining the effectiveness of the testing.

In contrast, high viscosity would hinder its ability to penetrate fine cracks, making it less effective. Low cost may be a consideration in selecting materials, but it does not necessarily correlate with the performance required for effective penetrant testing. Non-fluorescence generally does not contribute positively to penetrant efficacy as fluorescent penetrants offer significant advantages in visibility under UV light, aiding in the detection process. Therefore, the emphasis on wetting ability highlights its critical role in ensuring thorough and accurate inspections in liquid penetrant testing.