Characterization of historical pigments through imaging techniques, in various bands of the electromagnetic spectrum

Abstract

This paper proposes a proof of concept for the observation using multiband imaging techniques of 63 historical pigments (used from Antiquity to the 20th century). The response of these pigments has been documented at various points of the spectrum by constructing their images, by reflection, transmission, fluorescence, and false color, from the visible (VIS) to its two extremes, ultraviolet (UV) and infrared (IR). The study has been also completed with the radiographic image (RX). Each pigment responds differently in each of the techniques used, depending on its spectral behavior, which generates a unique behavior pattern for each material. The set of techniques used make up a methodology that proposes 11 possible ways of seeing, although it is in their transversal reading and confrontation where more complete results are achieved, th+rough an inductive method based on observation. This is a novel study, which although it has isolated precedents, summarizes for the first time in the form of images, the spectral behavior of such pigments. The results obtained intend, thus, to contribute to the improvement the interpretation of non-invasive imaging techniques applied to pictorial artworks, allowing the preliminary identification of some pigments.