Which type of penetrant is suitable for inspection under ordinary lighting conditions?

Visible dye penetrant is specifically designed for inspection under ordinary lighting conditions, which makes it suitable for situations where advanced lighting options may not be available. This type of penetrant is characterized by its bright coloration, allowing any discontinuities or defects in the surface being inspected to be easily visible to the naked eye.

The use of visible dye penetrants gives clear contrasts between the penetrant and the surface, facilitating detection of indications without requiring specialized lighting. In contrast, fluorescent dye penetrants typically need ultraviolet (UV) light to reveal indications, while solvent dye and thermal dye penetrants do not specifically cater to ordinary lighting conditions for visibility. Thus, visible dye penetrant stands out as the optimal choice for inspections where standard lighting is employed.