Fluorescence Spectroscopy: A Powerful Technique for the Noninvasive Characterization of Artwork

Abstract

After electronic excitation by ultraviolet or visible radiation, atoms and molecules can undergo thermal or radiative deactivation processes before relaxing to the ground state. They can emit photons with longer wavelengths than the incoming exciting radiation, that is, they can fluoresce in the UV-vis-near-infrared (NIR) range. The study of fluorescence relaxation processes is one of the experimental bases on which modern theories of atomic and molecular structure are founded. Over the past few decades, technological improvements in both optics and electronics have greatly expanded fluorimetric applications, particularly in analytical fields, because of the high sensitivity and specificity afforded by the methods. Using fluorimetry in the study and conservation of cultural heritage is a recent innovation. In this Account, we briefly summarize the use of fluorescence-based techniques in examining the constituent materials of a work of art in a noninvasive manner. Many chemical components in artwork, especially those of an organic nature, are fluorescent materials, which can be reliably used for both diagnostic and conservative purposes. We begin by examining fluorimetry in the laboratory setting, considering the organic dyes and inorganic pigments that are commonly studied. For a number of reasons, works of art often cannot be moved into laboratories, so we continue with a discussion of portable instruments and a variety of successful "field applications" of fluorimetry to works of cultural heritage. These examples include studies of mural paintings, canvas paintings, tapestries, and parchments. We conclude by examining recent advances in treating the data that are generated in fluorescence studies. These new perspectives are focused on the spectral shape and lifetime of the emitted radiation. Recent developments have provided the opportunity to use various spectroscopic techniques on an increasing number of objects, as well as the ability to fully characterize very small amounts of sample, either in a laboratory setting or on site. Thus, a new technological highway is open to scientists; it is still difficult to navigate but offers an enormous potential for investigating objects without touching them. Fluorescence spectroscopy is one of the most important of these techniques.

Near-Infrared Emission and Photon Energy Upconversion of Two-Dimensional Copper Silicates

“…This spectra feature was further used for identification of these pigments in artifacts 4 . These early investigation stimulated further effort in the search for mechanistic understanding of the NIR luminescence and its potential applications [5][6] .…”

Photoluminescence Properties of Zinc Oxide in Paints: A Study of the Effect of Self-Absorption and Passivation

“…18 Higher specific and reliable characteristics may be provided by the excitonic emission band, as already highlighted on model samples and real paintings. [19][20][21] Even though the exciton absorption onset is commonly utilized as a clue for the noninvasive identification of zinc white in nineteenth and twentieth century paintings, [22][23][24] the use of luminescence spectroscopy may offer high sensitivity in the case of complex mixtures of pigments.…”

Tibetan Printing: Comparison, Continuities, and Change

“…This allow for comparisons with contemporary artistic practice in other media and in other geographical areas. Despite major technical developments in recent years which allow reliable, non-invasive identification of many artists' materials (Bull et al 2011;Delaney et al 2010;Leona 2009;Miliani et al 2007Miliani et al , 2010Ricciardi et al 2012;Romani et al 2010;Rosi et al 2010;Vagnini et al 2009), the technical analysis of works of art on parchment and paper remains an under-developed field in comparison to the extensive analyses routinely carried out on other types of artwork, especially easel paintings (Neate et al 2011). One main reason for this is the widespread need to employ only non-invasive analytical methods to analyse works on paper, due to the general requirement to avoid sampling, i.e.…”