During X-ray film development, what happens to the grains in the emulsion?

During X-ray film development, the grains in the emulsion undergo a chemical reaction that results in the formation of a latent image, which is initially invisible. The emulsion consists of silver halide crystals that are sensitive to radiation. When exposed to X-rays, these crystals are altered, leading to the formation of a latent image that isn't visible until the film is processed through developer and fixer solutions.

The development process involves immersing the film in a developer solution, which reduces the exposed silver halide crystals to metallic silver, creating a visible image where the exposure occurred. However, this transformation does not occur instantly; the latent image needs the chemical development process to become visible.

Therefore, the correct answer highlights the foundational process of how X-ray film works: by first forming an invisible latent image that is later made visible through developing. Understanding this aspect is crucial in radiography, as it informs techniques for handling and processing films to obtain clear and accurate diagnostic images.