What does it mean if an indication reappears after the removal of the original developer?

When an indication reappears after the removal of the original developer, this typically indicates that there is still some penetrant present in a reservoir on or within the surface of the material being tested. This can happen for various reasons, such as the penetrant being trapped in a surface defect or porosity, or it may have been absorbed into the substrate.

In this scenario, the developer initially helps draw the penetrant out of the defect and makes it visible, but if some penetrant remains in the defect, it can reappear once the developer is removed. This behavior is crucial in assessing whether a defect is significant, as it suggests the defect has a capacity to contain fluid, which can indicate a problem in the material's integrity. Therefore, recognizing this phenomenon helps the technician make informed decisions regarding further testing or the need for repairs.