Honors Program


Date of this Version


Document Type



Guse J. The Characterization and Identification of Historic Inks by Raman Microspectroscopy. Undergraduate Honors Thesis. University of Nebraska-Lincoln. 2024.


Copyright Jordyn Guse 2024


When working with questioned documents, forensic examiners often perform handwriting analyses, but a chemical analysis of the ink used can provide insightful information about the age and authenticity of a document. Before the popularization of the ballpoint pen, ink used in historical documents was made of varying recipes, often with a base of gall or logwood extract, complicating the composition of the specific ink used. Additionally, the introduction of synthetic dyestuffs in ink presents further complexities to the ink sample. These variations lead to analytical challenges when characterizing or identifying the ink used in a historic document. Due to its non-destructive nature and sensitivity to varying chemical and structural characteristics, Raman microspectroscopy is an advantageous chemical analysis method for characterizing historic ink samples. A set of sixty historic ink samples were analyzed by Raman microspectroscopy using both a 532nm and a 785nm laser. Additionally, data was collected for known samples, which were either synthesized in the laboratory using historical ink recipes or purchased from suppliers. The Raman data was first analyzed by nominal color, then grouped across colors based on spectral similarities. The spectra of the unknown samples were also compared to the known spectra as well as those of various dyes, leading to several positive results based on spectral similarities. The results of this study support the potential of Raman spectroscopy in identifying historic inks, which can be applicable to questioned document analysis due to the unique spectra produced by different types of ink.