In radiography, which outcome is typically associated with an underexposed film?

• A. Pale image, dark background, translucent edges
• B. Dark image, light background, sharp edges
• C. Very bright image with white background
• D. No visible image

Answer: (A)

Underexposure means not enough X-ray photons reach the film, so not enough darkening occurs in the emulsion during development. The result is low optical density across the image, making it pale overall. The portions of film that were not irradiated or only lightly irradiated stay relatively dark in appearance, so the image contrast presents a pale structure against a darker background. The borders of structures can also appear less well defined, with edges that look translucent because the density changes are not fully developed. In short, insufficient exposure yields a pale image with a darker surrounding background and edges that aren’t sharply defined.