Physics and Astronomy Department, University of Bologna, Bologna, Italy.
Centro Fermi, Museo Storico della Fisica e Centro Studi e Ricerche "Enrico Fermi", Rome, Italy.
Magn Reson Chem. 2020 Sep;58(9):889-901. doi: 10.1002/mrc.5054. Epub 2020 Jul 14.
Paintings on canvas are complex structures created by superimposing layers of different composition. Investigations on the structure of these artworks can provide essential information on their state of conservation, pictorial technique, possible overpaintings, and in planning a proper conservation plan. Standard methods of investigation consist in sampling a limited number of fragments for stratigraphic analyses. Despite the recognized validity of these methods, they are affected by evident limitations. Nuclear magnetic resonance (NMR) profiling, often named NMR stratigraphy, is an NMR relaxometry technique applied by single-sided portable devices developed to overcome the disadvantages of microinvasive stratigraphic analyses. The potential of this approach on artworks, including wall paintings and a few examples of painted canvas, is described in the literature. In this study, NMR profiles of painting on canvas were examined by analyzing transverse relaxation time data by T quasi-continuous distributions and the results compared with standard stratigraphic cross-sections analysis. Combining signal intensity and T quasi-continuous distributions, the identification of textile, preparatory, and paint layers was enhanced. The diction "NMR stratigraphy" for these inhomogeneous layered artworks is also discussed. Indeed, unlike the stratigraphic cross-sections, NMR profiles provide information on a volume (flat slice), rather than on a surface, and the collected signal can derive from nonuniform and partially overlapping layers. This study paves the way for extensive investigations on relaxation time quasi-continuous distributions in various binder/pigment mixtures in order to improve the reliability of NMR profile as an innovative, non-invasive, and nondestructive method for analyzing paintings on canvas.
画布上的绘画作品是由不同成分的层叠结构组成的复杂结构体。对这些艺术品结构的研究可以提供有关其保存状态、绘画技术、可能的重绘以及规划适当的保护计划的重要信息。标准的研究方法包括对有限数量的碎片进行地层分析取样。尽管这些方法得到了公认的有效性，但它们也受到明显的局限性的影响。核磁共振（NMR）层析成像，通常称为 NMR 地层学，是一种应用于单一侧便携式设备的 NMR 弛豫率技术，旨在克服微侵入地层分析的缺点。该方法在艺术品中的应用，包括壁画和一些绘画画布的例子，在文献中已有描述。在这项研究中，通过分析横向弛豫时间数据的 T 准连续分布，对画布上的绘画 NMR 谱进行了研究，并将结果与标准地层横截面分析进行了比较。通过结合信号强度和 T 准连续分布，可以增强对纺织品、预备层和颜料层的识别。还讨论了这些非均匀层状艺术品的“NMR 地层学”术语。实际上，与地层横截面不同，NMR 谱提供了有关体积（平切片）而不是表面的信息，并且收集的信号可以来自不均匀且部分重叠的层。这项研究为在各种粘结剂/颜料混合物中进行弛豫时间准连续分布的广泛研究铺平了道路，以提高 NMR 谱作为一种创新的、非侵入性的、非破坏性的分析画布上绘画的方法的可靠性。
