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An Evaluation of Matching Unknown Writing Inks with the United States International Ink Library

Authors

  • Gerald M. LaPorte M.S.F.S.,

    1. United States Secret Service, Forensic Services Division, Questioned Document Branch, 950 H Street N.W., Washington, DC 20223.
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  • Marlo D. Arredondo M.F.S.,

    1. United States Secret Service, Forensic Services Division, Questioned Document Branch, Chemistry Contractor, 950 H Street N.W., Washington, DC 20223.
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  • Tyra S. McConnell M.S.F.S.,

    1. United States Secret Service, Forensic Services Division, Questioned Document Branch, 950 H Street N.W., Washington, DC 20223.
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  • Joseph C. Stephens B.S.,

    1. United States Secret Service, Forensic Services Division, Questioned Document Branch, Chemistry Contractor, 950 H Street N.W., Washington, DC 20223.
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  • Antonio A. Cantu Ph.D.,

    1. United States Secret Service, Forensic Services Division, Research Section, 950 H Street N.W., Washington, DC 20223.
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  • Douglas K. Shaffer M.S.

    1. United States Secret Service, Forensic Services Division, Questioned Document Branch, 950 H Street N.W., Washington, DC 20223.
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  • *This work was presented, in part, at the Mid-Atlantic Association of Forensic Scientists Annual Meeting, May 18–20, 2005, Pittsburgh, PA.

  • All references pertaining to manufacturers and their products do not imply endorsement by the United States Secret Service or the authors.

Additional information and reprint requests:
Gerald M. LaPorte, M.S.F.S.
United States Secret Service
Forensic Services Division
950 H Street N.W.
Washington, DC 20223
E-mail: gerry.laporte@usss.dhs.gov

Abstract

ABSTRACT: Utilizing a database of standards for forensic casework is a valuable resource. Undoubtedly, as more standards (and corresponding information about the specimens) are collected, there is a greater certainty of identification when a questioned and a known item cannot be distinguished after a series of analyses. The United States Secret Service and the Internal Revenue Service National Forensic Laboratory jointly maintain the largest known forensic collection of writing inks in the world, which is comprised of over 8500 ink standards collected worldwide, dating back to the 1920s. This study was conducted to evaluate the reliability of matching arbitrarily purchased pens with known inks from a database. One hundred pens were randomly obtained from a variety of sources and their respective ink compositions were compared with standards. Eighty-five of the inks were determined to be suitable for comparison utilizing optical examinations and thin-layer chromatography. Three of the inks did not match any of the specimens on record; one of these inks was similar to an ink from an identical brand of pen that was in the database, but had a modified formulation.

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