ISSN: 0022-1198
Page Count: 7

Ballpoint Ink Age Determination by Volatile Component Comparison—A Preliminary Study
Stewart, LF
Document analyst, United States Secret Service Forensic Services Division, DC

(Received 21 May 1984; accepted 29 June 1984)

Abstract

Ballpoint pen inks consist primarily of a mixture of dyes, resins, and vehicle components. The vehicles are used to solubilize or suspend dyes, resins, and other components as well as to provide smooth ball movement and flow of ink onto writing surfaces. These vehicles are relatively volatile and make up approximately 50% of the ink by weight. Extraction and formulation identification of the questioned ink is performed. Once identified, the volatile components of the ink are measured quantitatively by gas chromatography. Preliminary studies show that the relative proportions of these volatile ingredients decrease as the ink ages. How long an ink has been on paper is determined by comparison of the relative concentrations of the volatile components of the questioned ink with those of known inks (age) of the same formulation. The relationship between age of ink, storage conditions, and paper will also be discussed.

Keywords:
questioned documents, inks, gas chromatography, pens, age determination

Paper ID: JFS11819J
DOI: 10.1520/JFS11819J
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