During radiographic inspection, how do defects like cracks typically appear?

Defects like cracks during radiographic inspection appear as darker shadows on photographic paper. This occurs because the areas where there are defects, such as cracks, allow more radiation to pass through compared to the surrounding material. When the X-rays or gamma rays penetrate the component and hit the photographic film or paper, they expose it. This increased exposure in those areas results in darker spots or shadows on the film, clearly indicating the presence of a defect.

Understanding this phenomenon is critical in non-destructive testing, as it helps to identify structural integrity and safety issues within materials without causing any damage. Recognizing the appearance of defects in a radiographic image is essential for proper interpretation and analysis of the results.