Quantitative approaches for Fiber Optics Reflectance Spectroscopy (FORS)

Ricardo P. Vicente Rojas, Silvia Sotgiu, Véronique Cachia, Eugenio DelRe, Nicola Schiavon, Mauro Giustini, Mauro Missori
Abstract:
In this paper, Fiber Optics Reflectance Spectroscopy (FORS) was used to measure the concentration of pigments in paintings on a paper substrate. There is currently no agreement on a general quantitative approach using FORS, even if several attempts have been made in the past with varying degrees of success. In our approach, reflectance spectra were processed using the Kubelka-Munk (K-M) theoretical model of light propagation in an optical inhomogeneous medium. Experimental tests were carried out on mockups prepared using mixtures of two pigments (ultramarine blue and Naples yellow) and their reflectance spectra were acquired using a set-up with an integrating sphere. Given the linear relationship between the scattering and absorption coefficients of the pigments, and knowing the volume concentration of the pigments, the method enables both identification and quantification of components in the binary paint mixtures from FORS spectra.
Download:
IMEKO-Metroarchaeo-2025-048.pdf
DOI:
10.21014/tc26-2025.048
Event details
IMEKO TC:
TC26
Event name:
TC26 MetroArcheo Conference 2025
Title:

Metrology for Archaeology and Cultural Heritage

Place:
Bergamo, ITALY
Time:
15 October 2025 - 17 October 2025