What type of defect typically shows darker shadows during radiographic inspection?

In radiographic inspection, darker shadows indicate areas where there is a greater absorption of radiation, which typically occurs due to the presence of voids or disruptions in material integrity. Cracks and porosity, which includes small holes or voids in the material, reduce the density of the material in those areas, leading to increased penetration of the X-rays or gamma rays used during the radiographic inspection. As a result, these areas appear darker on the radiograph.

When cracks are present, they create a pathway that allows radiation to pass through more easily than the surrounding solid material. Porosity, which consists of smaller voids, similarly reduces the amount of material that can absorb the radiation, also resulting in darker areas on the film or imaging plate. This characteristic makes them identifiable defects during inspections.

Other types of defects, such as weld defects, material inclusions, and surface roughness, generally do not exhibit the same level of darkness associated with cracks and porosity. Weld defects may show irregularities but do not create significant voids that would allow for substantial radiation penetration. Material inclusions might absorb radiation differently depending on their density and composition, and surface roughness affects the finish of the material but does not create air-filled spaces that lead to darker imaging