DEVELOPMENT OF LATENT FINGERPRINTS USING A CORONA DISCHARGE

A novel technique for the development of latent fingerprints is presen ted. It is based on placing a fingerprint-bearing object inside a coro na discharge induced plasma. The development of various real and artif icial fingerprints on metallic substrates under a wide range of condit ions is studied. Using the results of the development experiments and the results of X-ray photoelectron spectroscopy, it is shown that the development is based on oxidation of the fingerprint background. This is achieved by strong oxidizers generated by the discharge process, wh ile saturated fatty-acids found in sebaceous fingerprints protect the area beneath them, resulting in a visible fingerprint. The process is optimized by minimizing the electrode gap distance and maximizing the peak discharge voltage and the pulse repetition frequency.