1. Examination of Paint
Examine two paint samples to determine same origin
Generally used in burglaries, hit-and-run accidents or vehicle accidents

2. Composition of Paint
Paint is composed of a binder, pigments and additives dissolved in a solvent
Paint is spread onto a surface and dries in a hard film
As it dries, the solvent evaporates leaving behind the binder and pigments suspended in it

3. Automotive Paint Layers
Electrocoat primer: applied to steel body to prevent corrosion, generally gray or black
Primer Surfacer: Completely smoothes out surface. Highly pigmented to minimize difference in color between basecoat and primer

4. Automotive Paint Layers, cont’d
Basecoat: Provides the color and finish of the car. Must be able to resist UV rays, weather and acid rain.
Clearcoat: Un-pigmented layer used to improve gloss and durability of the paint

5. Examination of Paint Color determination is used to identify paint
Two paint samples would be examined under stereoscopic microscope for color, surface texture and color layer sequence
An increase in the complexity of the layer structure gives a sample greater forensic value

6. Examination of Paint, cont’d
Use pyrolysis gas chromatography to determine paint formulation
IR Spectrophotometry is used to determine composition of paint
Analyze the inorganic pigments in paint using neutron activation analysis, X-ray diffraction and X-ray spectroscopy.
Compare paint make-up to color charts maintained by car manufacturers to determine make and year of car

7. Collection and Preservation of Paint Evidence
Pick up with forceps or scooped up with paper
Use druggist folds or glass vials to contain paint
Collect standard/reference sample when available using clean scalpel or Exacto Knife