Reticulin staining (such as Gomori's Reticulin Stain) is a specialized tissue staining technique that colors reticulin fibers black or dark brown against a pale (yellow or pink) background. The method relies on a silver deposition reaction on the surface of these fibers. Reticulin fibers are naturally found in the connective tissues of organs such as the liver, spleen, bone marrow, and lymph nodes, where they provide delicate structural support.