Determining Line‐Crossing Sequences Between Laser Printing and Writing Pen Using Coaxial Light

Abstract

Determining the application sequence of hand‐written pen ink and printer toner lines has attracted significant interest in questioned document examination. This study uses coaxial light to determine line‐crossing sequences, with intersections observed under a VSC600 forensic document workstation and a Leica M205A Stereo‐microscope. Results show that reflected light at intersections and color contrast between intersections and nonintersections was observed when a hand‐written ink line passes over a toner line, while a toner line passing over a written line appeared dull, with no color contrast. The procedure was tested under a range of conditions, such as types of writing pens and laser printers, the writer, and writing pressure, with the latter playing an important role in the evaluation. To validate the results, a 90% detection rate and 98% accuracy rate were achieved from 50 samples of blind testing, which is more effective than optical microscopy.

Interpol questioned documents review 2019–2022

“…including any other technology used to prepare the document. The following 64 articles [ [548] , [549] , [550] , [551] , [552] , [553] , [554] , [555] , [556] , [557] , [558] , [559] , [560] , [561] , [562] , [563] , [564] , [565] , [566] , [567] , [568] , [569] , [570] , [571] , [572] , [573] , [574] , [575] , [576] , [577] , [578] , [579] , [580] ] [ [581] , [582] , [583] , [584] , [585] , [586] , [587] , [588] , [589] , [590] , [591] , [592] , [593] , [594] , [595] , [596] , [597] , [598] , [599] , [600] , [601] , [602] , [603] , [604] , [605] , [606] , [607] , [608] , [609] , [610] , [611] ], combined with 17 presentations [...…”

“…And in 2021, another study of stamp ink impressions and laser-printed lines focused on the characteristics of the toner fusing characteristics [ 554 ]. Wu et al [ 555 ] studied the use of coaxial lighting to view the sequence of line crossings between electrophotographic processes (toner) and writing inks. The team of Binette et al used Mikrosil™ casting of the intersection of toner-printed lines with blue ballpoint pen ink lines to determine the sequence of strokes [ 556 ].…”