A Systematic Approach to Ink Identification

Abstract

A systematic approach to identification of writing inks is presented. This approach uses a multiple technique method for analysis of the inks to develop a large number of identifiable points for comparison. Well established methods are used for the analysis of inks, such as thin layer chromatography, spectrophotometry, and gas-liquid chromatography, in addition to traditional methods for comparison which use ultraviolet and infrared light. The inks are identified by comparing the results of the questioned inks with results obtained from a complete library of writing inks maintained by this laboratory. By using the described approach, most inks can be identified with a high degree of certainty.

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

“…TLC is one of the most widely used and generally accepted scientific methodologies used to compare and help characterize ink formulations. TLC has been discussed extensively by Witte (21), Brunelle and Pro (22), Brunelle and Reed (23), Brunelle and Crawford (24), Kelly and Cantu (25), and Aginsky (26). TLC analysis begins by removing an ink sample from a document, and subsequently extracting the ink in an appropriate solvent.…”

Ink Dating—The State of the Art

“…The author dated inks by matching questioned inks with ink standards that have known first production dates. He used multiple thin-layer chromatography, solubility tests, chemical spot tests, infrared reflectance, infrared luminescence, and densitometry to compare questioned and known inks [11,15]. Occasionally, gas chromatography was used to identify resinous materials in ink.…”

“…This sampling procedure, which does not destroy the legibility of the writing, has been accepted by the courts for over 20 years. Considerable interest in the dating of inks is reflected in the literature since this development and since the establishment of a comprehensive Standard Ink Reference Collection at the Bureau of Alcohol, Tobacco, and Firearms in 1968 [11]. The following discussion traces the development of ink dating techniques from 1937 to 1990.…”

Chromatic analysis of blue ballpoint pen inks and related dyes

“…1 Systematic approaches to ink comparison and identification have been described by Brunelle, Pro, Reed, and Cantu. [3][4][5] In particular, spectroscopic methods, including X-ray fluorescence spectroscopy, [6][7][8] and UV-vis spectroscopy, 9 and chromatographic techniques, including paper chromatography and thin layer chromatography (TLC), 1,10 have been extensively applied to ink analyses. Widely used in forensic science is TLC 1-5 because it does not require special apparatus and has the advantage of providing simple and direct operation.…”