Sudan Black B (also known as solvent black 3) is a fat-soluble diazo dye that was initially used for staining tissue sections. The dye was €rst prepared in Germany in the early 1930s and was proposed as a myelin stain in 1935 by Lison and Dagnelie [1]. Around the same time in England, it was proposed as a stain for fats. Its use as a dye stain for visualizing latent prints was €rst reported by Mitsui et al. in 1980 [2]. This formulation contained the dye along with ethylene glycol, ethanol or methanol, and water. This reagent successfully recovered latent prints on paper submerged in water for up to 10 days [3]. The reagent has also been recommended for rough, nonporous surfaces that have been wetted or have been contaminated with greasy or sticky substances [4].