Picture2

Fingerprints on stainless steel. Panel a) A ToF SIMS image of the surface of a stainless steel sample. This a combined image of the intensities/concentrations of sodium and potassium ions on the surface. Panels b-d) show optical images taken from the same region of the substrate containing the fingerprint after superglue fuming and exposure to fluorescent dyes Basic Yellow 40 (BY40), Crystal Violet (CV) and Sudan Black (SB).