The physical Application of Non-destructive Techniques in Detection the Sequence of Intersecting Gel Ink and Printed Laser Toner Strokes

Abstract

Determination the sequence of intersecting strokes is great evidence in the field of the authentication of documents. Two types of the intersection utilized in preparing the samples of gel ink and toner. The effect of the brands and models of a laser printer, the brands, and colors of gel pen, the nature of the paper surface and the time gap were studied. The samples were examined by two nondestructive techniques; the digital microscope and Raman spectroscopy. The ink properties observed under the digital microscope succeed in determining the sequence of intersection except in case of some colors of some pen brands. Raman spectroscopy combines with a digital microscope to analyze the samples which indistinguishable by the digital microscope. The combination of a digital microscope and Raman spectroscopy is an excellent forensic base to full discrimination the sequence of intersecting strokes regardless of the brands or colors of gel ink.