The recoverability of fingerprints on nonporous surfaces exposed to elevated temperatures

Previous work by the authors compared the effectiveness of ninhydrin, 1,8-diazafluoren-9-one (DFO), and physical developer (PD) as enhancement reagents for fingerprints deposited on paper that had been exposed to elevated temperatures. This research extends the previous study and investigates the recoverability of fingerprints deposited onto glass and ceramic surfaces in order to mimic the environment these surfaces may be exposed to within a fire scene. This research has shown that ridge detail is still retrievable from ceramic after exposure to 800°C (1472°F) for 20 minutes, although, at temperatures in excess of 350C (662F), ridge detail would only survive if the fingerprints had been protected from direct exposure to radiant heat and direct air flow across the surface. This investigation has shown that the most effective enhancement technique overall was found to be superglue followed by BY40 at all temperatures except 200 C (392F) in which case, iron powder suspension was superior. However, superglue followed by BY40 may have to be excluded as a prospective enhancement technique for many situations because the nonporous surface may become wet during firefighting activity. The use of silver vacuum metal deposition has been demonstrated to develop fingerprints after exposure to higher temperatures and may have future potential for this application.