Evaluation of available techniques for the recovery of latent fingerprints from untreated plywood surfaces

An evaluation of several current techniques available for the detection of fingerprints was undertaken to identify the technique(s) most suitable for recovering fingerprints from untreated plywood surfaces. This substrate is often encountered operationally, particularly in doors of local authority premises. This study evaluated the abilities of 13 fingerprint development techniques to enhance marks deposited on untreated plywood surfaces. Each detection technique was applied to fingerprints that had been deliberately planted on pieces of plywood by three donors who had been evaluated as "good", "average", and "poor" donors. The most successful fingerprint development techniques were then more rigorously tested on prints of varying ages, and effort was made to determine the most effective sequence for recovering prints from simulated casework. Of the techniques examined, both ninhydrin and physical developer were found to recover prints up to 28 days old. (Prints older than 28 days were not tested.) A dilution of household bleach was found to successfully darken prints weakly developed with physical developer, and the best recovery of fingerprints was achieved through the application of physical developer only, rather than with a sequence of techniques.