Robuta

https://www.ojp.gov/library/publications/spectroscopy-rare-earth-ruhemanns-purple-complexes SPECTROSCOPY OF RARE EARTH-RUHEMANN'S PURPLE COMPLEXES | Office of Justice Programs The complexes Ruhemann's Purples form with europium or terbium salts are well-suited for fingerprint development on strongly fluorescent surfaces because they... rare earthspectroscopy