Dynamic Role of Scanning Electron Microscopy Coupled with Energy-Dispersive X-ray Spectroscopy in Differentiating Overlapped Blue Pen Inks

Abstract

Documents serve as a testament to societal responsibilities, representing tangible evidence of interactions and agreements among individuals, organizations, and clients. The diversity of their form varies from printed, typewritten, or handwritten materials. This study highlights the dynamic role of scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX) in differentiating overlapped blue pen inks, providing a valuable tool for forensic document examination. In the present work, elemental analysis was conducted on blank paper, individual inks (B1, B2, G1, G2, F1, F2), and their respective overlap regions (B1B2, G1G2, F1F2) to investigate compositional variations. The overlap regions exhibited intermediate elemental profiles, reflecting contributions from both inks. Elevated carbon levels confirmed the organic composition of inks, while reduced oxygen and magnesium levels indicated ink coverage on the paper surface. Unique elemental markers, such as copper in gel inks, calcium in fountain pen ink F1, and sulfur in ink F2, enabled effective differentiation. Notably, palladium levels were significantly higher in overlap regions, indicating additive contributions from both inks. These findings emphasize SEM-EDX as a powerful, partially destructive technique for identifying individual ink formulations, distinguishing overlapping inks, and analyzing their interactions, despite its limitation in deciphering diverse texts.