What is the light-sensitive material that coats the film in radiographic imaging?

The light-sensitive material that coats the film in radiographic imaging is silver-bromide crystal. This compound is a key component in traditional radiographic films, where it provides the necessary properties to capture images when exposed to radiation. When ionizing radiation interacts with the silver-bromide crystals, it creates a latent image on the film, which can later be developed to produce a visible image.

Silver-bromide is particularly favored in film technology due to its high sensitivity to light and radiation, making it effective for capturing detailed images. Its halide properties allow it to react to various types of radiation effectively, a critical aspect in radiography.

Other materials mentioned, such as silver-chloride, calcium tungstate, and rare-earth phosphors, play different roles in imaging technologies but are not used in the film coating of traditional radiographic films. Silver-chloride, for example, is used in some photographic applications but not commonly in radiography. Calcium tungstate is a type of fluorescent material used in computed radiography systems, while rare-earth phosphors can be used in image receptors but are not part of the film itself.