Fingerprints Summer Project
Students on this project: TJ Petty and Will Vigor.
Resource for XPS: Martin Prutton - "Introduction to surface physics"
10 Days XPS
XPS Data
CL Data
EDX Data
(only in prototype stage)
Group A - Silver casings
Group B - Shiny brass casings
Group C - Not so shiny brass casings
Cleaning Method 1: Annealing in air
Method
A thermocouple was placed in thermal contact with the inside of the casing adjacent to the fingerprint. The casing was then slowly heated to 600°C and then allowed to cool in air. Previous studys have followed a simular method using brass discs. [1] [2]
Results
Cleaning Method 2: Annealing in N2
Results
End-on Optical Microscopy
Fingerprints
Cleaning Method 3: Annealing in a Vacuum
Results
End-on Optical Microscopy
Fingerprints
Cleaning Method 4: Plasma Cleaning
Method
The casing was placed inside a plasma cleaner for 4 minutes in an air plasma, a 10mA current was used.
Results
Cleaning Method 5: Sonication
Method
The casings were sonicated for 3 minutes in ethanol then allowed to dry naturally in air. The casings were then sonicated in acetone for 3 minutes the solvent was then allowed to evaporate. Previous studies have washed in acetone with out the use of sonication. [1] [3] [4]
Results
Cleaning Method 6: Soapy Water
Method
Add two to three drops of commercial detergent to water at 30-40°C. Rub vigorously for 30 seconds with a wet tissue and then pat dry with a tissue. This method was taken from [1] and has previously been investigated [5].
Results
References
[1]-E Paterson, Bond J W, Hillman A R, A Comparison of Cleaning Regimes for the
Effective Removal of Fingerprint Deposits from Brass. J Forensic Sci 2009;55:221.
[2]-Williams G, McMurray HN, Worsley DA. Latent fingerprint detection
using a scanning Kelvin microprobe. J Forensic Sci 2001;46:1085–92.
[3]-Williams G, McMurray N. Latent fingermark visualization using a scan-
ning Kelvin probe. Forensic Sci Int 2007;167:102–9.
[4]-Migron Y, Mandler D. Development of latent fingerprints on unfired
cartridges by palladium deposition: a surface study. J Forensic Sci
1997;42:986–92.
[5]- Bond JW. Visualization of latent fingerprint corrosion of metallic sur-
faces. J Forensic Sci 2008;53:812–22.