Paint_Analysis for Forensic Sciences.ppt

Basic concept to understand in using paint as evidence.

1. Paint Analysis

2. What crimes involve paint?

3. •Hit and Run
•Burglary
Painting forgery

4. Paint Analysis
Comparative studies to
see if from common
source
Paint
Chip
On
Victim
Suspect Car
No Suspect
Car
Paint Chip On Victim
May be able to
determine color,
make and model of
car

5. What is Paint?

6. Paint=
•Mixture of pigments (Color)
•Additives
•Binder Compound
•Solvent (Evaporates when paint applied)

7. Auto Paint
1.Electrocoat Primer:
Onto steel
Resists Corrosion
Black to Grey

8. Auto Paint
2. Primer Surfacer:
Smooth out surface, hides seams
Light Grey or Red

9. Auto Paint
3. Basecoat:
a.k.a. Colorcoat
“eye appeal”
may have metal flakes

10. Auto Paint
4. Clearcoat:
Unpigmented
Glossy

11. Paint As Evidence
•Individual Characteristics or Class
Characteristics?

12. Class unless……
Multilayered Paint Chip Custom Finishes

13. Problem
•A single type of car paint can be on many
different models
•For a given color/type of paint, batches don’t
vary much in composition
•Binder chemical composition may vary very
slightly from batch to batch
What to do? What to do?

14. •Perform pyrolysis on paint sample coupled
with gas chromatography
•Polarized light microscopy
•Emission spectroscopy
•Neutron activation
•X-ray diffraction
•X-ray spectroscopy
Paint Analysis

15. PDQ (Paint Data Query)
•Law enforcement
database of specific
paint formulas added
onto cars since 1974

16. Art Fraud and Paint
•Need to show materials in a painting were
unavailable in the real time that they were
made

17. Case Study
•“Shroud of Turin”
•Christ’s Death
Shroud?
•Christ's blood on
linen?

18. Human dried
blood on linen
(Brown)
“Christ” blood on
linen (Red)
1000X-Red Ochre
Pigments
1000X-Real
blood (Brown)

19. Hans Van Meegeren
Traded fake paintings for genuine
artwork in the 1930s

20. Christ and the Disciples at Emmaus
Supposedly an undiscovered
masterpiece by Vermeer

21. Johannes Vermeer
Last Supper supposedly
by Vermeer

22. Technique
•Used a synthetic phenolformaldehyde
resin -known as Albertolor Ambertol-
dissolved in a spirit such as turpentine
and/or an essential (i.e., non-fatty) oil such
as oil of lilac or oil of lavender, which
would then be mixed with hand-ground
powder pigments.

23. •He heated the resin transforming its
chemical composition so that chemical
tests would show it is really not the
chemical it actually was
•He painted over low value17
th
century
paintings. He scraped away old painting

24. “Leveling Paint”

25. http://www.youtube.com/watch?
v=4FF3kxtL058&feature=related
•http://www.youtube.com/watch?v=
YP8nmaNQeoQ&feature=relmfu