National Center for Forensic Science

Paint

Paints are characterized by several physical and chemical characteristics.  Physical characteristics may include color, layer sequence, layer thickness, surface features, layer features, contaminants, and weathering.  Chemical components may include pigments, polymers, and additives.  These characteristics are determined by macroscopical, microscopical, chemical, and instrumental methods.  Paint analysis may be for purposes of comparison between questioned and known samples or identification of a motor vehicle make, model, and years of manufacturer.   Comparison of questioned and known samples search for differences in appearance, layer sequence, size, shape, thickness, or some other physical or chemical feature.  The goal of the examiner is to assess the significance of any observed differences.  Identification of a motor vehicle make, model, or year of manufacture entails making chemical and color comparisons of the undercoat and topcoats of a questioned sample to paint standards and databases of color and composition information.

Reference: Scientific Working Group on Materials Analysis, “Forensic Paint Analysis and Comparison Guidelines”, http://media.wix.com/ugd/4344b0_86bdd7f917894e07a94d61b8ae2c439b.pdf, May 2000, accessed March 10, 2016.

NCFS research:

1.A comparative chemometric analysis of automotive paints with data obtained by Laser Induced Breakdown Spectroscopy (LIBS) to Scanning Electron Microscopy – Energy Dispersive Spectroscopy (SEM-EDS).

For more information contact Dr. Michael Sigman.