What is the cause of white spots appearing on a dental film?

White spots appearing on a dental film are caused by trapped air bubbles during the processing of the film. When the film is placed into the developer solution, if air bubbles are present, they can adhere to the film surface. This prevents the developer from properly reaching those areas, resulting in the areas under the bubbles not being developed, which manifests as white spots on the finished film.

In contrast, excessive exposure to light generally results in a completely darkened film or fogging rather than distinct white spots. Scratches on the film surface may create streaks or lines but do not result in white spots as air bubbles do. Lastly, improperly mixed processing solution could lead to issues such as inadequate development or inconsistent film quality but is not specifically associated with the appearance of white spots; instead, it might lead to other artifacts or overall poor imaging quality.