CLPEX Chat Board

Dust prints are generally a removal of a layer of dust on a surface. The dust has three-dimensional properties. Does this mean that a dust print would be (should be) classified as a patent print or a plastic print?

Just a small debate in my office...

If we are measuring the surface relief between ridges and furrows in microns, then I imagine that the residue of a sweat print would have three dimensions, too.

I would suggest that, in a plastic print, the ridges & furrows modify the substrate. I think you could argue that, in a dust print, the substrate is not modified by the ridges & furrows. Unless you define the dust as the substrate.

Obviously, they're elimination prints, because the dust has been eliminated in the process of deposition.

Alternatively you could argue they don't exist because they're not mentioned in the SWGFAST terminology document.

The designation of patent/latent/plastic on dust prints has previously been stated in the following article:

IAFIS - Two Murdered Schoolteachers and a Single Patent Print in Dust”, Gary Krohn, JFI 51:6(2001)

I believe that the term plastic print is intended for impressions in a malleable substance or surface.

In Canada they are referred to as "take away prints".
As for the 3-D nature of the prints, you could say powdered prints are 3-D as well. I'll defer to the wisdom of Ernie and agree that plastic prints are prints in a malleable or viscous substance.

Shane Turnidge

Shane,

Thanks for the "wisdom" tag, but it was BASIC latent print knowledge, probably learned from first IAS lessons. (Let some of the current practitioners wonder about that reference)

Your take-away label is similar to a term I used when I was doing some data collection on track evidence and needed a descriptive term. I settled on "subtractive" track to describe track evidence as a result of footwear or tire contact removing substance from a substrate as opposed to an "additive" track when features were added to the substrate by contact.

Ernie