Researcher(s)
- Walique Richardson, Electrical Engineering, University of Delaware
Faculty Mentor(s)
- Roxanne Radpour, Art conservation / Electrical and Computer Engineering, University of Delaware
Abstract
Non-Destructive Spectroscopy of Inks and Pigments Using THz-TDS and FORS
Walique Richardson, Professor Roxanne Radpour, Professor Benjamin Jungfleisch
Non-invasive and non-destructive applied spectroscopy is an essential tool in the analysis and preservation of cultural heritage materials. It allows researchers to uncover critical information about the history, composition and structure of historical objects without sampling. At the University of Delaware, there are many advanced spectroscopy techniques, laboratories and instrumentation available. We focus here on two specific techniques: Terahertz Time-Domain Spectroscopy (THz-TDS) and fiber optic reflectance spectroscopy (FORS). THz-TDS provides insights into the internal structure of objects by recording reflections of terahertz pulses at interfaces of refractive index change, allowing it to reveal subsurface features such as layer thicknesses, cracks and voids, and hidden elements in an artwork. On the other hand, FORS performs surface molecular and color analysis by identifying pigments, varnishes, and binders based on their reflectance across different wavelengths. Together, these differing yet complementary techniques significantly enhance conservation strategies and art historical research by offering a deeper understanding of the materials, techniques, and condition of culturally significant objects. This work presents the data collection and spectral analysis from the applications of these two techniques, utilizing instruments in the Imaging Science Laboratory For Cultural Heritage (FORS) and from the Jungfleisch Research Group (THz-TDS). Two different studies were conducted: 1) Diffuse reflectance spectroscopy to evaluate the material composition of painted pigments to reveal information such as their chemical composition and their optical properties based on how the pigments reflect at different wavelengths. 2) Different ink samples on paper (applied alone and layered) examined with terahertz time-domain spectroscopy to investigate important diagnostic features of their applications such as layering of ink or ink thickness, an important line of inquiry in forensic document analysis.