Journal of Forensic Sciences/ July 2007

Κυκλοφόρησε το νέο τεύχος του Journal of Forensic Sciences (JOFSC), Volume 52, Number 4, July 2007. Ακολουθούν τα περιεχόμενά που αφορούν τηε Δικαστική Γραφολογία:

The new issue of the Journal of Forensic Sciences (JOFSC), Volume 52, Number 4, July 2007 has been released.Here are the contents of the articles concerning Questioned Documents:

• D.L.Hammond: Validation of LAB color mode as Nondestructive Method to differentiate Black Ballpoint Pen Inks (pp.967)
• S.Sugawara: Passport Examination by Polarized Infrared Spectrum (pp. 974)

http://www.blackwell-synergy.com/toc/jfo/52/4

ABSTRACTS:

Passport Examination by Polarized Infrared Spectra

Abstract: In this study, a new nondestructive technique for passport examination is proposed. In this technique, linearly polarized light is used to measure Fourier transform infrared (FT-IR) reflectance spectra of films on the biographical data page. Thirty genuine and thirty-five counterfeit Japanese passports and five marketed films pasted on name cards were examined. The measured spectra were analyzed as follows. The absorption spectra were obtained by the Kramers–Kronig transformations of reflectance spectra. The peak ratios were then calculated from the absorption spectra by adding the peak areas at 1126 and 1263 cm1 and dividing the result by the peak area at 1727 cm1. When nonpolarized light was used, the samples could not be distinguished by comparing the peak ratios. However, when polarized light was used, they were successfully distinguished by the comparison. Therefore, polarized light is useful for the forensic discrimination of passport films by the measurement of FT-IR spectra.

Validation of LAB Color Mode as a Nondestructive Method to Differentiate Black Ballpoint Pen Inks

Abstract: Nondestructive digital processing methods such as lab color mode (available in Adobe® Photoshop®) are emerging as alternative methods for forensic document examiners to use when attempting to differentiate writing instrument inks. Although these techniques appear to be viable, little data currently exists regarding the known or potential error rates associated with these techniques. Without adequate data, the validity and reliability of these techniques, including lab color, can not be established. In an attempt to begin to address these issues, 44 black ballpoint ink pens were obtained and used to create 990 pen-pair samples for analysis using established lab color mode techniques. No erroneous findings of "different" were reported following the examination of the known pen-pair combinations in which the same pen was used to create the samples (n = 44). Of the remaining 946 samples, 737 pen-pair samples were differentiated using the lab color mode method, while 209 samples were unable to be differentiated and were recorded as either being "similar" (n = 153) or "unsure" (n = 56). Comparison of the lab color mode results with the results obtained through additional testing using traditional infrared reflectance and infrared luminescence test methods showed that lab color differentiated 102 pen-pair samples (11%; 102/946) that were not differentiated using a VSC-4C.