Electrochemical enhancement of latent fingerprints using copper film deposition on metal objects

Abstract Visualization of fingerprints on irregular metal objects is crucial in forensic practice, and electrochemical deposition of copper films provides a simple and effective solution in this regard. Latent fingerprints were visualized by chronoamperometric reduction of Cu 2 ⁺ from a 0.02 M copper sulfate solution in 0.1 M sulfuric acid. The deposition parameters were optimized for stainless-steel (−0.450 V vs. Ag/AgCl, 180 s) and brass (−0.250 V vs. Ag/AgCl, 120 s) and successfully applied to real objects (coins, keys, and cartridge cases). Fingerprint details were evaluated using a stereoscopic microscope. All samples showed fingerprint quality suitable for identification. The method is fast, cost-effective, and applicable to curved or irregular surfaces, making it a promising tool for practical forensic applications. Graphical Abstract