Determination of Crossing Sequences by VF20 High Mag Fluorescence Microscope

In the practice of document examination, the number of cases involving the determination of crossing sequence of printed and written strokes is increasing year by year, but there is a lack of national and industry technical standards for the identification of cross-timing between printed strokes and handwriting. This study created crossed stroke samples formed by random combination of black inkjet printing devices (categorized into dye-based ink and pigment-based ink) and ballpoint pen with different brands and models in different orders, and a VF20 three-dimensional high-magnification video fuorescence microscope was used to examine those samples. Additionally, through the control variable method and the single variable method, the study investigated the effects of factors such as paper, time interval between two kinds of ink marks, writing cushion and printing mode on the determination results of the crossing sequence between inkjet printer ink and ballpoint pen ink. The results showed that when the ink from two types of inkjet printers and ballpoint pen intersect in the same crossing sequence, there were some differences in microscopic performances. And except the printing mode factor, other variables had no significant infuence on the result judgment. Therefore, for different types of crossed stroke samples, sequencing the superimposed lines with black inkjet printing ink versus ballpoint pen ink by VF20 High Mag Fluorescence Microscope is feasible. This research can provide important reference for the examination of related cases, and meet the increasing demand for sequencing the intersections of printed strokes with handwriting.