Used as a counterstain in histology, particularly in muscle and connective tissue staining protocols. It provides contrast to other dyes like hematoxylin or eosin by coloring background tissues, enhancing the visibility of cellular structures. Commonly applied in trichrome staining methods to differentiate collagen from muscle fibers, where it stains collagen green or light green, allowing clear microscopic distinction. Its yellowish tint helps achieve balanced color contrast in final tissue sections, improving diagnostic accuracy in pathological evaluations.