Application of Ink Chemistry to Unveil Document Forgeries

Authors: Weeraratna T

DOI: 10.23880/ijfsc-16000408

Volume 9, Issue 3

Abstract

The Examination of Questioned Documents (EQD) Laboratory in Sri Lanka is the sole institution authorized to issue case reports to courts of law and other law enforcement agencies. The EQD lab handles a wide range of cases involving questioned documents, including handwriting and signature analysis, counterfeit documents, typewritten documents, charred documents, and questioned rubber stamp impressions, among others. Questioned document cases often involve alterations, additions, and obliterations made with visually similar inks. Although these inks may appear alike, they can be distinguished due to differences in their chemical composition. The non-destructive physical examination of inks on documents typically involves microscopic examination under visible light, followed by analysis using other selective spectral regions, such as ultraviolet and infrared, available in the VSC 8000 (Foster+Freeman, UK). Writing inks with different chemical compounds react differently to various light sources, making this variation valuable for identifying forgeries in questioned documents.

Keywords: Thermochromic Ink; Infra-Red Luminescence; Ultra-Violet Radiation

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