ASNT Radiographic Testing Practice Test 2026 – Comprehensive All-in-One Guide for Exam Success!

Radiographic undercutting primarily occurs due to side scatter, which refers to the scattering of radiation that happens when the x-rays or gamma rays strike the material being inspected and bounce off at angles. This scattering can cause the radiation to reach areas on the film that were not intended to be exposed, leading to dark spots or an overall darkening in areas that should remain lighter. This phenomenon can obscure critical details in the radiographic image, affecting the interpretation of welds or joints and potentially masking defects.

The other options, while they might affect film quality, do not specifically lead to undercutting. Film fogging, for instance, entails a general reduction in image clarity and contrast due to unwanted exposure, primarily to ambient light or radiation, while underexposure results in a lack of adequate film density. Improper film handling typically leads to scratches, bends, or other physical damage to the film. While all these factors can degrade image quality, they do not directly create the specific artifact known as undercutting, making side scatter the primary culprit in this context.