AT THE INTERSECTION BETWEEN CHEMISTRY AND ART: SCIENTIFIC RESEARCH FOR THE STUDY AND PRESERVATION OF CULTURAL HERITAGE

摘要

The creation of a work of art is a process often depicted as untouched by material constraints. Pure, unfettered inspiration, without the limitations imposed by physics. It should be evident, however, that only with materials having defined physical properties a certain esthetic effect can be obtained. Works of art are complex technological objects: their appearance and their performance over time are the results of a careful selection of materials and techniques. Thus, artists' choices can be interpreted not just in the classical framework of art history, but in a holistic approach encompassing esthetics and technology. In absence of direct testimony from their often anonymous creators, masterpieces of the past become key material evidence in our efforts to retrace the working practices of artists, the technical knowledge and esthetic preferences of ancient cultures, and the complex trade patterns linking distant empires. The quest for color, for beauty is a fundamental constant in human history, as well as an economic engine, and an inspiration for art and technology alike. While we easily recognize that the desire to produce richer and more lively images is a clear driver to seek new materials, on the other side of the world, in mines or forests, or in the crucibles of the alchemist (or of his modern counterpart, the chemist), we often overlook how new materials lead to new esthetics. Scientific investigations have expanded significantly our understanding of works of art, often upending traditional interpretations. A typical example is the rediscovery and investigation of the original polychromy of ancient Greek and Roman sculpture, once a contested topic and now an established research field. Many more cases highlight the importance of the work of cultural heritage scientists, not only in investigating works of art, but also in developing the techniques that make these studies possible. Examples include the discovery of the earliest organic pigment, in a 4,000 years old Egyptian leather fragment; new insights into the global trade of dyes in the Middle Ages; and closer to us, the introduction of synthetic pigments and dyes in the 19th centuries, from the craze for mauveine to Van Gogh's unfortunate passion for geranium lakes, passing by Hokusai's experiments with Prussian blue in the Thirty-six views of Mount Fuji, and the color revolution prompted by the arrival into Japan of the aniline dyes in the Meiji period. Using advanced analytical chemistry, from x-ray fluorescence spectrometry to Raman and surface-enhanced Raman spectroscopy, from electron microscopy to mass spectrometry, we can build a material history of art based on physical evidence gathered from masterpieces spanning four millennia, from ancient Egypt to Modernity, demonstrating that technological developments were not only readily embraced, and often prompted by artists and their audiences, but also that they in turn created new forms of expression, in a continuous dialogue between materials and meanings.