Paint Analysis
What crimes involve paint?
Hit and Run Burglary Painting forgery
Paint Analysis Comparative studies to see if from common source Paint Chip On Victim Suspect Car May be able to determine color, make and model of car No Suspect Car Paint Chip On Victim
What is Paint?
Paint= Mixture of pigments (Color) Additives Binder Compound Solvent (Evaporates when paint applied)
Auto Paint Electrocoat Primer: Onto steel Resists Corrosion Black to Grey
Auto Paint 2. Primer Surfacer: Smooth out surface, hides seams Light Grey or Red
Auto Paint 3. Basecoat: a.k.a. Colorcoat “eye appeal” may have metal flakes
Auto Paint 4. Clearcoat: Unpigmented Glossy
Paint As Evidence Individual Characteristics or Class Characteristics?
Class unless…… Multilayered Paint Chip Custom Finishes
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?
Paint Analysis Perform pyrolysis on paint sample coupled with gas chromatography Polarized light microscopy Emission spectroscopy Neutron activation X-ray diffraction X-ray spectroscopy
PDQ (Paint Data Query) Law enforcement database of specific paint formulas added onto cars since 1974
Art Fraud and Paint Need to show materials in a painting were unavailable in the real time that they were made
Case Study “Shroud of Turin” Christ’s Death Shroud? Christ's blood on linen?
Human dried blood on linen (Brown) “Christ” blood on linen (Red) 1000X-Real blood (Brown) 1000X- Red Ochre Pigments
Hans Van Meegeren Traded fake paintings for genuine artwork in the 1930s
Christ and the Disciples at Emmaus Supposedly an undiscovered masterpiece by Vermeer
Johannes Vermeer Last Supper supposedly by Vermeer
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.
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
“Leveling Paint”
http://www.youtube.com/watch?v=YP8nmaNQeoQ&feature=relmfu http://www.youtube.com/watch?v=4FF3kxtL058&feature=related