Which penetrant test processes commonly use the same penetrants?

The reason the choice, which includes both water washable and solvent removable penetrant test processes as commonly using the same penetrants, is correct lies in the compatibility of the penetrant materials used in both processes.

Water washable penetrants and solvent removable penetrants are designed to have similar chemical properties and compositions to ensure that they can adequately reveal surface defects in non-porous materials. Both types of penetrants are formulated to penetrate into surface discontinuities effectively. However, their removal methods differ—water washable penetrants can be removed using water, whereas solvent removable penetrants require a solvent for clean-up. This reflects the fact that although the application methods differ, the core penetrant formulations can be alike, allowing for flexibility in method selection based on testing requirements and environmental conditions.

While solvent removable and post emulsifier penetrants are used in different contexts related to the emulsification process, they do not share the same penetrant materials as the other options. Similarly, stating that none of the above processes share the same penetrants would overlook the established compatibility between water washable and solvent removable types.