What symptom indicates that a film may be underexposed?

The correct response is that the outer film wrapping tab being visible indicates that a film may be underexposed. In dental radiography, an underexposed film typically means that there was insufficient exposure to radiation, which results in a film that does not register the intended details adequately. When the film is underexposed, it often fails to adequately capture the necessary contrast and density required for clear interpretation.

If the outer film wrapping tab is still visible after processing, it is a clear sign that the film did not receive enough exposure, as the tab itself should blend into the overall image when exposure levels are appropriate. The user's ability to see this tab suggests that the surrounding film area has not adequately exposed and developed properly.

Other symptoms, such as overly dark images or the presence of a halo effect, indicate different issues related to exposure settings or processing errors. Clear visibility of images and the halo effect would not align with the concept of underexposure but rather excessive exposure or improper processing. Understanding these relationships helps ensure high-quality diagnostic images in dental practice.