Unexposed silver halide crystals are removed from the emulsion by which solution?

The correct answer is sodium thiosulfate, as it serves as a fixing agent in the development process of radiographic films. When a film is developed, the silver halide crystals that have been exposed to X-ray or light undergo a chemical reaction to form metallic silver. However, the unexposed silver halide crystals must be removed to prevent further exposure or fogging of the film.

Sodium thiosulfate effectively dissolves these unexposed silver halide crystals, allowing them to be washed away during the fixing stage. This step is crucial for ensuring that the final image is clear and that any potential for further developing or fogging of the film is eliminated. The use of sodium thiosulfate in the fixing process enhances the permanence and stability of the radiographic image.

Other substances listed, like hydroquinone and alcohol, serve different functions in the photographic or film development process. Hydroquinone is primarily a developing agent that reduces the silver halide to metallic silver in the areas that received exposure. Alcohol is not typically involved in the radiographic film processing and does not play a role in the removal of silver halide crystals. Water, while used in various stages of the development process, is not a fixing agent and does