Microreflectance FTIR Techniques Applied to Materials Encountered in Forensic Examination of Documents

Abstract Microreflectance Fourier transform infrared spectrometry (FTIR) has been applied to the forensic examination of documents. The materials examined were black printing inks, paper, plastics, photocopy toners, and transfer letters (Letra set). Good discrimination was achieved between different samples of these materials. Euclidean distances were calculated on the bases of first derivatives of measured FTIR reflectance spectra. Some results were compared with those obtained by diffuse reflectance FTIR. Microreflectance FTIR is nondestructive to the materials and may be used as a complement to optical techniques for examination of documents.