What determines film speed in dental radiography?

Film speed in dental radiography is primarily determined by the size of the silver bromide crystals present in the film. Larger crystals are more sensitive to radiation, allowing them to produce a diagnostic image with less exposure time than smaller crystals. This means that films with larger silver bromide crystals have higher speed, requiring less radiation to create an image, thus improving patient safety by reducing radiation exposure.

The choice related to the amount of silver bromide salt does have an impact on the film's sensitivity, but it is fundamentally the size of the silver bromide crystals that is the critical factor in determining film speed. Additionally, while the thickness of the cellulose acetate base could affect the physical properties of the film, it does not influence the sensitivity or speed directly. Lastly, the size of the film exposed pertains to the dimensions of the imaging medium but does not play a role in the film's sensitivity characteristics related to exposure.