Identifying Automotive Vinyl Wraps in Forensic Cases

A recent study published in the journal Forensic Chemistry tested a new method for distinguishing automotive vinyl wraps using infrared (IR) and Raman spectroscopy, filling a gap in forensic trace-evidence analysis as the wrap material becomes increasingly common on vehicles.¹

What are vinyl wraps?

Vinyl wraps are sheets that are deployed when a car owner wants to change a vehicle’s color or finish.² They are a direct alternative to repainting.²

Because vinyl wraps come with key advantages, including being less expensive and reversible, car owners are increasingly turning to using them to change the looks of their vehicles.² As a result, fragments of vinyl wraps are more likely to turn up at crime scenes as trace evidence. However, because vinyl wraps are only beginning to grow in popularity, there is currently no standardized analytical protocol existed for comparing recovered wrap fragments to a source vehicle or product.¹

What did the study investigate?

In their study, the researchers examined vinyl wrap samples spanning three manufacturers, four colors, and two surface finishes (gloss and matte). The research team analyzed both the vinyl backing and the adhesive layer with attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) and Raman spectroscopy.¹ The team then applied chemometric modeling, such as principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), to determine how reliably the resulting spectra could sort samples into their correct product class.¹

What were the results of the study?

The researchers found that ATR-FTIR analysis was reliable in sorting the ten product classes. For classification accuracy of the backing layer, the researchers achieved 73% at the more granular roll level, while the adhesive layer reached 77% under ATR-FTIR.¹ Raman spectroscopy of the backing added complementary value, correctly classifying samples 70% of the time, though its performance dropped sharply for adhesives, at 45%, and for dark-pigmented materials generally.¹

The chemical explanation differs between the two techniques. ATR-FTIR discrimination stemmed largely from variation in the polymer matrix and plasticizer content of the polyvinyl chloride (PVC) backing.¹ By contrast, Raman spectroscopy drew its discriminating power from inorganic pigments.¹ Notably, Raman spectra distinguished a gloss and matte white sample from the same manufacturer based on differing titanium dioxide (TiO₂) content.¹

For black samples, the researchers found Raman spectroscopy was not as effective. Strong laser absorption by carbon black pigment suppressed the signal almost entirely.¹ The adhesive layer likewise proved less discriminating overall, since most manufacturers appear to use chemically similar acrylic pressure-sensitive adhesives.¹ One manufacturer's product, VViViD, stood out with an unusual spectral feature suggesting a distinct acrylic formulation.¹

Combining the four analytical results created a workflow that narrowed the pool of confusable samples to a single pair.¹

What are the key takeaways from this study?

The main takeaway from this study is that the researchers pieced together a new analytical sequence for studying vinyl fibers found at crime scenes. The study demonstrates that beginning with ATR-FTIR of the backing layer should come first because it does most of the discriminating work on its own.¹ Next, to fix the remaining ambiguities, Raman analysis can provide the supplementary evidence needed.¹

Another key takeaway is that vehicle-related investigations are common, especially as more drivers are entering the roadways. Given the increase in popularity of vinyl wraps, it is becoming more important that scientific methods for analyzing them at crime scenes are effective.¹ Future studies are expected to expand on this work, as there remains limited standardized protocols on analyzing vinyl wraps.

References

1. Spaulding, J. S.; Brassington, L. A.; Edwards-Dugan, C. M. Forensic Characterization and Discrimination of Automotive Vinyl Wraps Using ATR-FTIR and Raman Spectroscopy with Chemometric Classification. For. Chem. 2026, 49, 100749. DOI: 10.1016/j.forc.2026.100749
2. Teague, C. Is a Vinyl Car Wrap Worth It? Carfax, 2026. https://www.carfax.com/maintenance/car-wrap (accessed August 28, 2026).