U.S. flag

An official website of the United States government, Department of Justice.

Development of an Analytical System for the Forensic Comparison and Identification of Fiber Dyes on Casework-Sized Fibers

NCJ Number
Date Published
February 2016
17 pages
In order to overcome identified challenges to generalized fiber dye characterizations, this research explored a significant range of dyestuffs that span numerous major dye application classes, chemistries, chromophores, and fiber types, using techniques and methodologies currently available in most forensic laboratories.

The techniques and methodologies used include thin layer chromatography, Raman microscpectroscopy, Fourier transform infrared micro spectroscopy, Ultra-Violet/Visible spectrophotometry, and microspectrophotometry. The research relied on a colorant collection that Microtrace has sourced and compiled over several decades. Numerous aspects of dye analysis, from extraction through micro analytical characterization, classification, and identification were examined for a set of 300 commercially prevalent dyestuffs. The results show that dye identification can be conducted by using techniques available in many labs. The submitted and in-preparation publications will provide formalized approaches to obtaining this data; will illustrate the increased evidentiary significance of such data; and will provide examples of casework in which this approach, coupled with the reference data accumulated in this project, have been applied to identify dyestuffs. It is anticipated that this research will provide a basis from which laboratories can expand their approach from a generalized comparison of color between questioned and known materials to a specific identification of the colorants present in a sample. This has the potential to increase the significance of results in the prosecution or defense of a case. The results also have the potential to improve the value of investigative leads in cases for which a comparison sample does not exist by constraining or identifying specific dyes. In some cases, it is possible to determine the specific manufacturer of a dye and its concentration in the fiber. 15 references and appended list of dyes studied in this research, a table of dyed fibers studied, and abstracts of submitted manuscripts

Date Published: February 1, 2016