Final answer:
A latent image is the pattern of exposure on a photographic film caused by chemical changes in the film's emulsion when exposed to radiation, and it becomes visible after the development process.
Step-by-step explanation:
A film that has been exposed but has not yet been processed has a pattern of exposure that is called a latent image. This latent image is invisible and is created by the chemical alteration of the film's emulsion when it is exposed to radiation. Whether the radiation comes in the form of visible light or ionizing radiation, such as X-rays or gamma rays, it interacts with the silver compounds in the film's emulsion. This exposure creates a chemical change that, after development, becomes a visible image. Notably, the process is not completely efficient, with not all radiation interacting and not all interactions resulting in this chemical change. Hence, the final image quality depends on various factors, including the amount and type of radiation, as well as the use of absorbers or other devices to fine-tune the image information.