Latent fingermark visualisation using a scanning Kelvin probe

The current state of the art in fingermark visualisation on metallic surfaces by a scanning Kelvin probe (SKP) technique is described. Latent eccrine fingermarks deposited on a range of polished and roughened metallic surfaces can be effectively imaged. Results are presented which show that the SKP technique is able to visualise fingermarks obscured beneath optically opaque soot films and retrieve ridge detail in instances where fingermarks have been physically removed (e.g. by rubbing with a tissue) from a metal surface. SKP Volta potential mapping of small, severely non-planar metal objects such as fired brass cartridge cases is demonstrated.