Paint_Analysis for Forensic Sciences.ppt
- 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
- 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
- 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 Albertol or 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 value17th century paintings. He scraped away old painting
- 24. “Leveling Paint”