Deciphering the Chemistry of Cultural Heritage: Targeting Material Properties by Coupling Spectral Imaging with Image Analysis.

The chemical study of materials from natural history and cultural heritage, which provide information for art history, archeology, or paleontology, presents a series of specific challenges. The complexity of these ancient and historical materials, which are chemically heterogeneous, the product of alteration processes, and inherently not reproducible, is a major obstacle to a thorough understanding of their making and long-term behavior (e.g., fossilization). These challenges required the development of methodologies and instruments coupling imaging and data processing approaches that are optimized for the specific properties of the materials. This Account discusses how these characteristics not only constrain their study but also open up specific innovative avenues for providing key historical information. Synchrotron methods have extensively been used since the late 1990s to study heritage objects, in particular for their potential to provide speciation information from excitation spectroscopies and to image complex heritage objects and samples in two and three dimensions at high resolution. We examine in practice how the identification of key intrinsic chemical specificities has offered fertile ground for the development of novel synchrotron approaches allowing a better stochastic description of the properties of ancient and historical materials. These developments encompass three main aspects: (1) The multiscale heterogeneity of these materials can provide an essential source of information in the development of probes targeting their multiple scales of homogeneity. (2) Chemical alteration can be described in many ways, e.g., by segmenting datasets in a semiquantitative way to jointly inform morphological and chemical transformation pathways. (3) The intrinsic individuality of chemical signatures in artifacts triggers the development of specific strategies, such as those focusing on weak signal detection. We propose a rereading of the advent of these new methodologies for analysis and characterization and examine how they have led to innovative strategies combining materials science, instrument development, history, and data science. In particular, we show that spectral imaging and the search for correlations in image datasets have provided a powerful way to address what archeologists have called the uncertainty and ambiguity of the material record. This approach has implications beyond synchrotron techniques and extends in particular to a series of rapidly developing approaches that couple spectral and spatial information, as in hyperspectral imaging and spatially resolved mass spectrometry. The preeminence of correlations holds promise for the future development of machine learning methods for processing data on historical objects. Beyond heritage, these developments are an original source of inspiration for the study of materials in many related fields, such as environmental, geochemical, or life sciences, which deal with systems whose alteration and heterogeneity cannot be neglected.

[Synchrotron-based characterization methods applied to ancient materials (I)]. / Micro-imagerie de matériaux anciens complexes (I) Mikro-bildgebung komplexer antiker materialen (I).

This article aims at presenting the first results of a transdisciplinary research programme in heritage sciences. Based on the growing use and on the potentialities of micro- and nano-characterization synchrotron-based methods to study ancient materials (archaeology, palaeontology, cultural heritage, past environments), this contribution will identify and test conceptual and methodological elements of convergence between physicochemical and historical sciences.

[Expertise and construction of artistic value (14(th) to 15 (th) centuries)]. / Expertise et Construction de la Valeur Artistique (XIV(e)-XV (e) siècle) Expertise und Konstruktion des Künstlerischen Wertes (14. und 15. Jahrhundert) Conocimiento Experto y la Construcción del Valor Artístico (Siglos XIV-XV) 1415.

Working from a body of Tuscan commission contracts from the 14(th) and 15(th) centuries, this article shows how painting was the object of concrete evaluative practices among professional painters before becoming the subject of discussion for scholars and humanists. This study rests on the legal and economic analysis of clauses of expertise by which painters and commissioners submitted the work to other painters in order to guarantee the proper execution of the contract, thus constituting an essential evaluative measure for the economy of painting.

[The ladder game. An international history]. / Jeux d'echelles. Une histoire internationale.

The book Jeux d'echelles. La microanalyse a l'expérience, which appeard in 1996 under the direction of Jacques Revel, was translated in Italy in 2006 by the Viella editions under the title Giochi di scala. La microstoria alla prova dell'esperienza. This occasion seemed propicious for a historiographic and epistemological return to the microhistorical experience between France and Italy. It had to do with cross reperencing the reflections of a French historian and those of an Italian philosopher to seek to place in evidence, from a distance, the theoretical presuppositions of microhistory, and to measure the displacements undergone.