A light image of a backing "B" on a processed radiograph is probably caused by what?

The appearance of a light image of backing "B" on a processed radiograph is typically due to backscatter. Backscatter occurs when radiation is deflected or scattered from its original path and strikes the film unintentionally. This can often happen when the radiographic setup includes materials that can reflect or scatter radiation, such as the backing material of the radiographic film.

In radiographic testing, it's crucial to minimize backscatter to ensure the clarity and accuracy of the radiographic image. The presence of a light image implies that less radiation reached the film in that area, which is a hallmark characteristic of backscatter. This effect can lead to misleading interpretations of the radiograph, as it may obscure or alter the appearance of critical features in the image.

Understanding the causes and effects of backscatter is essential for ensuring high-quality radiographs and for troubleshooting any anomalies that may arise during the testing process.