Processing Latent Prints

This week in lab students learned how to process latent (invisible) fingerprints utilizing physical and chemical techniques. Physical methods are those that do not involve a chemical reaction occurring (such as using inorganic or magnetic fingerprint powder). Chemical methods are those that involve a chemical reaction occurring between the reagent and the component residues within the fingerprint (such as iodine, cyanoacrylate ester or "super glue", and ninhydrin).

Students were quick to realize that fingerprint processing is a delicate task, one which is much more difficult and requires much more patience and experience than perhaps is shown in prime time forensic dramas. The students were able to make use of chemicals (such as ninhydrin) that must only be used in ventilated environments due to the forensic investigation lab being equipped with two Air Science Downflow Work Stations which filter the air and allow for a safe environment in which to conduct processing efforts.

While some students displayed frustration with the quality of their developed prints, they were reminded that criminals don't typically leave perfect prints. Therefore, perfect prints are not developed, the prints are simply developed as perfectly and professionally as is possible.

Next week, trace evidence analysis!