VMD will develop latent prints on almost any substrate and it is important to understand that the use of other metal processing will increase the chances of latent print recovery.
Gold and Zinc can always be used first in the processing order. If no prints are developed, be sure to process the item with a single stage metal. At GoEvidence Forensic Laboratories we use the Silver on a regular basis, followed by Zinc.
Until a VMD user is familiar with the proper metals to use on a substrate, it is helpful to keep a substrate and consumable log to validate what metal development gives you the best results. Until you have the knowledge of what metals work best, the first and safest step is to process with Gold and Zinc, examine and photograph . The second step can be a single stage metal (Silver, Sterling Silver, Aluminum, Copper, Tin, etc.). Process, examine and photograph. Zinc will be the final metal process if desired.
There are latent prints that do not develop with the gold and zinc. Therefore, it is essential to process the item with a single stage metal (e.g. silver, sterling silver, aluminum, copper, tin, etc.). You can get a silver/chrome contrast on dark substrates by using zinc for the final metal process.
Items with an asterisk (*) may only develop with a single stage metal. Should be processed with a single stage metal to increase latent print recovery. For a chrome/silver contrast, use zinc for the final metal process.
Fabric + Currency*
Untreated Wood / Wetted Paper*
Paper with Plastic*
Adhesive + Non-Adhesive Sides of Tape*
Waxed Paper + Cardboard*
Soft Vinyl, Leather, & Rubber*
Plastic with Paper*
Textured Plastics & Coated Metals*