An Examination of the Sequence of Intersecting Lines using Microspectrophotometry

The potential of microspectrophotometry as a technique to determine the sequence of intersecting lines was examined. The technique was used to determine the sequence of heterogeneous line intersections produced using inkpad, stamp‐pad ink and ballpoint pens, gel pens, fountain pens, laser and ink‐jet printers. The study was carried out with an assumption that the peak characteristics of spectra from the point of intersection should correspond to the peak characteristics of pure ink which was executed later. According to spectral reflectance curves, microspectrophotometry was possible to determine whether the ink was above or below the inkpad/stamp‐pad ink seals. In blind testing, microspectrophotometry technique results were directly compared to those obtained by five experienced forensic document examiners using optical microscopy regularly employed in casework. As the results obtained from the study were positive, microspectrophotometry technique was found to be very successful in determining the sequence of heterogeneous line intersections under some conditions.