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On the Criteria for the Discrimination of Inkjet Printer Inks Using Micro-Raman Spectroscopy

NCJ Number
Journal of Raman Spectroscopy Volume: 49 Issue: 11 Dated: 2018 Pages: 1791-1801
Date Published
11 pages
The goal of this research project was to determine whether Raman data collected from the three cyan, magenta, and yellow microscopic colored dots can provide a chemical signature of sufficient discriminating quality to produce reliable investigative leads in a time effective and nondestructive manner.

Inkjet printers are ubiquitous devices in our society. It is not surprising, therefore, that they are used to commit different types of illicit activities, such as threats or extortions by means of anonymous letters, frauds in the context of disputed contracts, alterations to or counterfeit of ID documents, or counterfeit of currency banknotes. This latter application was of primary interest in the current study, where a method to rapidly develop investigative leads was required. Inkjet printed documents produce microscopic colored dots that can be detected using a microscopical approach in conjunction with Raman spectroscopy. In the current phase of this reported study, the criteria necessary to achieve discriminations between inkjet printer inks from different manufacturers, the same manufacturers, and even the same models have been evaluated on a set of 11 samples. Although Raman spectroscopy is already a relatively well established method for the characterization of colorants (both dyes and pigments), this study demonstrates that the contribution of minor peaks within Raman spectra improves the discriminating capabilities of the technique. The joint consideration of the three colored components was also effective in differentiating inkjet printer ink samples, especially those from the same manufacturer and in some instances from the same model as well. (publisher abstract modified)

Date Published: January 1, 2018