Ammonium sulfite is widely used in the photography industry as a component in developing solutions. It acts as a reducing agent, helping to convert exposed silver halides into metallic silver, which forms the image on photographic film or paper. In the textile industry, it serves as a reducing agent in dyeing processes, aiding in the fixation of dyes to fabrics. Additionally, it is employed in water treatment to remove excess chlorine from water systems, acting as a dechlorinating agent. Its reducing properties also make it useful in certain chemical synthesis processes, where it helps in the reduction of various compounds. Ammonium sulfite is also utilized in the pulp and paper industry to bleach and process wood pulp, improving the quality and brightness of the final paper product.