Which metals are primarily used in the Vacuum Metal Deposition process?

The Vacuum Metal Deposition (VMD) process is widely used in latent print development primarily due to the unique properties of certain metals. Gold and zinc are the metals that are particularly effective in enhancing the visibility of latent fingerprints on various surfaces.

When applying VMD, gold is often used because it bonds well with organic materials that are present in fingerprints, allowing for a clearer contrast. Zinc, on the other hand, provides a protective layer that helps in increasing the adherence of the developed prints, especially on porous surfaces. The deposition of these metals happens in a vacuum chamber, which allows precise control over the thickness of the metal layers, ultimately enhancing the quality and clarity of the developed prints.

These metals' effectiveness in adhering to fingerprint residues makes them the preferred choice in the VMD process, affirming the validity of the answer regarding their role in forensic applications. The other metals listed do not share the same level of compatibility or effectiveness for developing latent prints as gold and zinc do.