Detailed Procedure:

 

To collect questioned paint chips and particles:

1. Photograph the chips in place.

2. Wear eye protection, breathing protection (if necessary), and new, unused, clean latex or nitrile gloves.

3. Using disposable tweezers or other appropriate tool, carefully pick up the chips without crushing them and place them in a suitable container; an evidence or pharmacy fold is preferred. Collect paint chips from each location separately and package separately. Do not mix chips from different areas.

4. Place the evidence or pharmacy fold in an envelope and seal the container with evidence tape. Initial and date the tape.

5. Label the container with identifying information, including case number, date, exhibit number, a brief description, and your name.

6. Store the item in a secure location, such as a locked evidence van or your vehicle, until you are able to transport it to the laboratory.

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Laboratory testing of paint chips and particles:

Paint can be analyzed to determine class characteristics (color, chemical, and elemental composition) and mode of application (eg: layers of paint). Questioned and known samples can be associated on these bases. If multiple layers of paint are present, a high degree of association may be made based on the number, sequence, and relative thickness of the layers as well as the individual characteristics of each layer. It is possible, although rare, to physically match a paint fragment to a known source based on fracture edges, surface striations, and layer structures.

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Source:

"SWGMAT Web Site." Scientific Working Group for Materials Analysis, Website, July 1, 2013.