It is employed as a common biological stain for tissues and cells. Used to make inks and shoe-polish and for dyeing leather, wood, textiles, and plastics. The crude mixture of nigrosine hydrochlorides (Phenol Black L) is used to dye phenolic resins. Bases are used to make printing colors and to dye plastics. It finds its use in Dorner?s spore stain, as a negative stain in place of India ink for spirochetes, bacteria, protozoa and fungi. It is also used in compounding resins include phenolic resins, styrenics, polyamides and urea resins.