Strengths, Limitations, and Recommendations for Instrumental Color Measurement in Forensic Soil Characterization

Christine E. Dong, Jodi B. Webb, Maureen C. Bottrell, Ian Saginor, Brad D. Lee, Libby A. Stern

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Color determination of soil evidence is often done by visual comparison to soil color charts. A handheld spectrophotometer was tested with representative materials for its suitability for forensic soil characterization. Instrumental colorimetry provides accurate colorimetry with ~10-fold better precision than a soil color chart. The minimum sample size for accurate color determination was between 0.02 and 0.04 mg of fine soil for the specific instrument tested. Reporting colors in the L*a*b* space permits quantification of ΔE00, a measure of perceptible color difference, could enable objective quantification of small color differences and thresholds for forensic soil comparisons. A ΔE00 greater than ~ 3.5 to 6 likely indicates disparate soil sources in a forensic comparison, in the absence of confounding factors like sample alteration. Despite the superior precision of instrumental colorimetry, this approach is inappropriate for samples which are mottled at an inseparable scale, attached to a substrate, or too small for instrumental measurement.

Original languageEnglish
Pages (from-to)438-449
Number of pages12
JournalJournal of Forensic Sciences
Issue number2
StatePublished - Mar 1 2020

Bibliographical note

Publisher Copyright:
© 2019 American Academy of Forensic Sciences. This article has been contributed to by US Government employees and their work is in the public domain in the USA.


  • color contrast
  • color difference
  • colorimetry
  • forensic geology
  • forensic science
  • forensic soil
  • soil
  • soil color
  • spectrophotometry

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Genetics


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