Istituto CNR di Scienze e Tecnologie Molecolari (CNR-ISTM), c/o Dipartimento di Chimica, Universita degli Studi di Perugia, via Elce di Sotto 8, I-06123 Perugia, Italy.
Acc Chem Res. 2010 Jun 15;43(6):728-38. doi: 10.1021/ar100010t.
Driven by the need to study precious and irreplaceable artworks without compromising their integrity, researchers have undertaken numerous efforts to develop noninvasive analytical tools and methodologies that can provide a chemical description of cultural heritage materials without any contact with the object. The challenge is that artworks are made of complex mixtures, often with heterogeneous and unknown layered materials. Their components must be identified over a range of size scales, from the molecular identification of constituent compounds to the mapping of alteration phases. In this Account, we review recent research in spectroscopic techniques accessible from the mobile laboratory (MOLAB). The lab is equipped with an array of state-of-the-art, portable, and noninvasive instruments specifically tailored to tackle the different issues confronted by archaeologists, curators, and conservators. The MOLAB approach is suitable for studying a variety of objects, from ceramics to manuscripts or from historical wall paintings to contemporary canvases. We begin by discussing issues related to the acquisition and interpretation of reflectance or backscattered spectra from the surface of heterogeneous materials. Then we show how the selectivity needed for the noninvasive identification of pigments in paintings, even in mixtures or in layered matrices, can be acquired by combining elemental information from X-ray fluorescence with molecular and structural insights from electronic and vibrational spectroscopies. Discriminating between original pigments and restoration retouches is possible, even when both comprise similar chromophores, as highlighted in the study of paintings by Jordaens and Raphael. The noninvasive approach permits the examination of a very large number of artworks with a virtually limitless number of measurements. Thus, unexpected and uncommon features may be uncovered, as in the case of a lead pyroantimonate yellow doped with zinc that was discovered by micro-Raman and X-ray fluorescence on an Italian Renaissance majolica. For characterizing binding media, we discuss the strengths and limitations of using mid- and near-FTIR (Fourier transform infrared) spectroscopies supported by a multivariate statistical analysis, detailing the study of organic materials in a wall painting by Perugino and a survey of the painting technique on 18 contemporary paintings by Burri. In Michelangelo's David, we show how the noninvasive mapping of contaminants and alteration phases might inform decisions on preventive conservation plans. The multitechnique MOLAB approach overcomes the intrinsic limitation of individual spectroscopic methods. Moreover, the ability to analyze artworks without the need to move them is an invaluable asset in the study and preservation of cultural heritage.
为了在不损害艺术品完整性的前提下对珍贵且不可替代的艺术品进行研究，研究人员付出了诸多努力，开发出了无需接触艺术品即可对文化遗产材料进行化学描述的非侵入式分析工具和方法。然而，艺术品是由复杂的混合物构成的，其通常包含不均匀且未知的层状材料。这些材料的成分必须在不同的大小尺度范围内进行识别，从分子水平上鉴定组成化合物到绘制变质相图。在本综述中，我们回顾了可从移动实验室（MOLAB）获取的光谱技术的最新研究进展。该实验室配备了一系列最先进的、便携式的、非侵入式仪器，这些仪器专门针对考古学家、策展人和文物保护者所面临的不同问题而设计。MOLAB 方法适用于研究各种不同的对象，从陶瓷到手稿，从历史壁画到当代画布。我们首先讨论了从异质材料表面获取和解释反射或背散射光谱时所涉及的问题。然后，我们展示了如何通过结合 X 射线荧光的元素信息与电子和振动光谱的分子和结构信息，获得绘画中颜料的非侵入式识别所需的选择性，即使在混合物或层状基质中也是如此。如在对 Jordaens 和 Raphael 的画作的研究中所展示的，甚至当原始颜料和修复润色都包含相似的生色团时，也可以对其进行区分。非侵入式方法允许对大量艺术品进行几乎无限数量的测量，从而可以揭示意想不到的和不常见的特征，如在一件意大利文艺复兴时期的马略卡陶器上发现的掺锌的铅焦锑黄，该发现是通过微拉曼和 X 射线荧光分析得到的。为了对结合介质进行表征，我们讨论了使用中红外和近红外傅里叶变换（FTIR）光谱的优势和局限性，并结合多元统计分析进行了详细研究，分析了佩鲁吉诺壁画中的有机材料和对 18 件 Burri 当代画作的绘画技术的调查。在米开朗基罗的《大卫》中，我们展示了如何通过非侵入式绘制污染物和变质相图来为预防性保护计划提供决策依据。MOLAB 的多技术方法克服了单一光谱方法的固有局限性。此外，无需移动艺术品即可对其进行分析的能力，是研究和保护文化遗产的宝贵资产。
