Deck 12: Chemical Processing Methods: Nonporous Substrates

Question 1

What is the definition of a nonporous substrate?

Answer 1

A substrate that is not permeable to gases and liquids

Question 2

List three examples of nonporous substrates.

Answer 2

a. Glass
b. Metal
c. Plastic

Question 3

What happens when a latent print is deposited on a nonporous surface?

Answer 3

a. The latent print residues remain on the surface of the item until they are wiped away or destroyed by environmental factors
b. While the water evaporates, the insoluble compounds, and the compounds that do not evaporate with the water, remain on the surface
i. Lipids
ii. Waxy compounds
iii. Amino acids
iv. Sodium chloride
v. Urea

Question 4

latent prints developed with chemical reagents on porous items are always florescent.

Question 5

Why are fingerprints left on nonporous substrates more fragile than fingerprints left on porous substrates?

Question 6

What steps must be taken in order to preserve nonporous items of evidence collected from a crime scene?

Question 7

How are nonporous items processed for fingerprints at a crime scene?

Question 8

What is the first processing step when attempting to develop fingerprints on a nonporous surface?

Question 9

What process follows cyanoacrylate fuming in the processing sequence for nonporous items?

Question 10

What is the recommended processing sequence for processing porous items for fingerprints?

Question 11

What is the chemical name for superglue^®?

Question 12

cyanoacrylate fingerprints or two-dimensional.

Question 13

Define the terms vaporization and polymerization as they relate to cyanoacrylate fuming.

Question 14

What are the various components of the latent print residue that have been suggested as initiators for polymerization?

Question 15

What is the purpose of adding humidity to a cyanoacrylate fuming chamber?

Question 16

What are the components of the cyanoacrylate fuming chamber?

Question 17

Why is it necessary to include a control fingerprint when processing fingerprints in a cyanoacrylate fuming chamber?

Question 18

Why are cyanoacrylate dye stains used?

Question 19

How our dye stains applied?

Question 20

List three cyanoacrylate dye stains.

Question 21

What color goggles or filters are used for each of the following colors of light?

Question 22

At what wavelengths are rhodamine dye stained items visualized? What color light source is used to visualize the rhodamine dye stained cyanoacrylate prints? What color barrier filter is used?

Question 23

At what wavelengths are ardrox dye stained items visualized? What color barrier filter is used?

Question 24

What are the benefits of a one step fluorescent cyanoacrylate process?

Question 25

What is a disadvantage of the one step fluorescent cyanoacrylate process?

Question 26

What is the premise for vacuum metal deposition (VMD)?

Question 27

Which metals are used for the vacuum metal deposition process?

Question 28

What is MMD?

Question 29

How is SMD different from MMD?

Question 30

What is the definition of a semi-porous substrate?

Question 31

What is one potential latent print processing sequence for semi-porous items?