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Strengths, Limitations, and Recommendations for Instrumental Color Measurement in Forensic Soil Characterization
Author(s) -
Dong Christine E.,
Webb Jodi B.,
Bottrell Maureen C.,
Saginor Ian,
Lee Brad D.,
Stern Libby A.
Publication year - 2020
Publication title -
journal of forensic sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.715
H-Index - 96
eISSN - 1556-4029
pISSN - 0022-1198
DOI - 10.1111/1556-4029.14193
Subject(s) - colorimetry , color measurement , environmental science , soil test , color difference , sample (material) , forensic science , skin color , remote sensing , computer science , soil water , artificial intelligence , soil science , chemistry , computer vision , geology , geography , chromatography , archaeology , enhanced data rates for gsm evolution
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 Δ E 00 , a measure of perceptible color difference, could enable objective quantification of small color differences and thresholds for forensic soil comparisons. A Δ E 00 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.