Forensic Analysis of Commercial Inks by Laser-Induced Breakdown Spectroscopy (LIBS)

Abstract

<jats:p>Laser-induced breakdown spectroscopy (LIBS) was tested for all of the relevant issues in forensic examinations of commercial inks, including classification of pen inks on one paper type and on different paper types, determination of the deposition order of layered inks, and analysis of signatures and toners on one questioned document. The scope of this work was to determine the potential of a single LIBS setup that is compatible with portable instruments for different types of ink analysis, rather than building a very large database for inks and papers. We identified up to seven metals characteristic for the examined inks, which allowed to fully discriminate all eight black inks on one type of printing paper. When the inks were tested on ten different papers, the correct classification rates for some of them were reduced for reasons thoroughly studied and explained. The replicated tests on three crossing points, each one involving a pair of blue or black inks, were successful in five cases out of six. In the test simulating documents of forensic interest (questioned documents), LIBS was able to correctly identify the differences in three inks used for signatures on one of the three pages and the use of different printing inks on each page of the document.</jats:p>

A Spectroscopy-Network-Based Method for Forgery Detection of Documents

“…The analysis of spectroscopy has been developed to become crucial in the development of forensic science. The study of Cicconi et al, [9] used LIBS for testing issues related to the commercial inks. The study performed classification on pen inks for one paper type and various paper types, determination of the deposition order of layered inks.…”

“…http:// journals.uob.edu.bh Cicconi et al, [9] Documents with Signatures LIBS spectroscopy Needs complex computations Ameh and Ozovehe [10] Printed Documents FT-IS Needs Complex Computations Zieba et al, [11] Degraded Papers Infrared and Raman Complex to implement due to 2D correlations Buzzini et al, [12] Inkjet Printer Inks Micro-Raman High computational cost due to several technologies involved. Borba et al, [13] Blue Ballpoint Pen Inks PCA, HCA, and PLS-DA Needs complex computations Zieba and Kunicki [14] Several Types of Inks Micro-FTIR, Raman, and XRF Lead to the destruction of the examined document.…”

A Novel LIBS Sensor for Sample Examinations on a Crime Scene

“…A recent pan-European forensic round robin study on document forgery reported comparative results regarding the discrimination of papers, pen signatures, and toners by various analytical tools where only LIBS provided all correct responses in the blind test [ 5 ]. In studies of the questioned documents, determining the chronology of deposition of inks on paper is of outmost importance, and this task, difficult also for complex laboratory instruments [ 9 ], has been achieved by LIBS [ 10 ].…”

A Review of Laser-Induced Breakdown Spectroscopy (LIBS) for Document Examination: Fundamentals, Mechanism, and Application

“…Although the use of written documents in the modern age of technology has declined, handwritten signatures and notes continue to be widely utilized by the public as proof of consent [2]. Forged signatures and hand-written alterations on legal documents are still issue in civil and criminal investigations [2,3]. Therefore, ink analysis of these documents has become indispensable in the field of document examination.…”