The mechanisms of forensic vacuum metal deposition (fVMD): A literature review

Since the early 1970s, forensic vacuum metal deposition (fVMD) has been used in operational casework. It is renowned for its sensitivity and ability to work on aged impressions and difficult substrates. However, the precise mechanism by which this development occurs remains unclear. This article examines the current literature on fVMD to see what is known about the technique, what is unclear, and what are the next steps that should be taken. This review shows that, while the operational utility of the technique is not in question, none of the currently posited theories can explain all the observed phenomena. They are therefore, at best, incomplete, and further research is required.