Visualization of Latent Fingerprints on Aluminum

For aluminum, a new visualization method is presented in which copper is deposited electrochemically. The fingerprint on the aluminum (trace carrier) serves as an insulator as it prevents direct contact between electrolyte and aluminum. The decisive factor is the choice of an ammoniacal copper sulfate solution, which acts as a corrosion inhibitor due to the ammonia molecules. This enables uniform copper deposition on aluminum and thus the development of a clearly defined negative image.