Assessing the Possibility of Identifying the Chronological Sequence of Superimposed Printed and Handwritten Lines in Counterfeit Documents Produced by Various Printing Machines and Rollerball Pens.

Background: In forensic science, it is difficult to prove that questioned documents are authentic. One common way to commit document fraud is to change the original information by adding printed or handwritten strokes on top of it. Aim: Assess the effectiveness of digital light microscopy and ultraviolet (UV) light analysis in establishing the chronological order (whether printing or signature occurred first) of superimposed lines on counterfeited documents. It also aims to examine and analyze various interactions between strokes from rollerball pens and those produced by the three printing technologies (inkjet, laser, and photocopier) to identify forensic indicators of sequence. Methods: A total of 270 documents were produced utilizing inkjet, laser, and photocopier printers, with signatures applied using a blue rollerball pen in two separate sequences: signing prior to printing and printing prior to signing. Results: The findings demonstrate that microscopic analysis of color variations at intersection sites (e.g., black versus red discoloration) and the effects of mechanical disruption (toner deterioration following folding or scraping) consistently indicate the sequence. UV analysis showed inconclusive results, and thickness measurements revealed no significant differences between the groups. Conclusion: The research findings concluded that digital microscopy serves as a valuable tool for forensic analysis, whereas UV and thickness-based techniques demonstrate restricted effectiveness in determining sequences within superimposed documents.