Which process removes remaining silver halide from emulsion and hardens gelatin?

The process that removes remaining silver halide from emulsion and hardens gelatin is known as fixing. In photographic processing, fixing involves the use of a chemical solution, typically composed of ammonium thiosulfate or sodium thiosulfate, which effectively dissolves unexposed silver halide crystals on the film or paper. This step is crucial because it ensures that the image formed is stable and will not change or degrade in light.

Additionally, the fixing process contributes to hardening the gelatin layer of the emulsion, making it less susceptible to damage and ensuring the integrity of the image during further handling and processing. Proper fixing is essential for achieving a final product that retains the desired quality and longevity.

Other options describe different processes involved in photography. For instance, hardening refers specifically to the treatment that may occur separately to strengthen gelatin but does not encompass the removal of silver halide. Developing is the process that involves converting exposed silver halide into metallic silver, resulting in a visible image, while washing is the step that removes residual chemicals and fixers from the film or paper after fixation. Together, these steps form the essential sequence in film processing, but the specific action of removing silver halide while hardening gelatin is uniquely accomplished during the fixing