Which characteristic affects the speed of X-ray films?

The grain size of the film significantly influences the speed of X-ray films. Film speed, or sensitivity, is determined by how quickly the film can respond to radiation exposure and produce a detectable image. A film with larger grain size will typically be more sensitive to radiation, resulting in faster exposure times. This is because larger grains have a greater surface area for interaction with incoming X-rays, allowing for a more efficient conversion of radiation into a latent image.

Conversely, films with smaller grains generally require more exposure because they are less sensitive to radiation. This characteristic is crucial when selecting films for specific applications where time efficiency and image quality are critical factors, such as in industrial radiography or medical imaging. Understanding the role of grain size enables technicians to choose the appropriate film for their radiographic testing needs.