Which penetrant is suitable for inspections that need to be performed under ordinary lighting conditions?

Visible dye penetrant is suitable for inspections under ordinary lighting conditions because it is designed specifically for visibility without the need for specialized lighting equipment. This type of penetrant contains dyes that are easily seen under standard light sources, making it ideal for use in environments where fluorescent lighting or black lights are not available.

Fluorescent dye penetrants, while they provide excellent sensitivity and can detect very fine flaws, require UV light to fluoresce and reveal the indications. Therefore, they are not suitable for inspections under normal lighting conditions.

Water-washable penetrants and post-emulsifiable penetrants refer to the methods used for removing excess penetrant after inspection, rather than the visibility of the dye itself. While these can be effective in certain situations, their effectiveness does not directly relate to inspection visibility under ordinary lighting conditions. Visible dye penetrants offer the distinct advantage of ease of use and straightforward interpretation in typical lighting environments, which is why they are the correct choice for such inspections.