During the conservation of easel paintings, black draperies or dark backgrounds often prove problematic to treat and understand in terms of condition. Despite most black pigments in Old Master paintings not intrinsically containing high atomic number elements, the investigation of black paints is one of the National Gallery's major uses and most helpful applications of x-ray fluorescence (XRF) scanning. As a visual tool, XRF element distribution maps of black paints are useful for assessing the extent of overpainting or condition of any surviving original paint beneath, and for revealing the original modelling. However, interpreting the XRF element maps can be challenging. It is important to consider not only the primary compositions of black or dark pigments, but to have an understanding of other possible associated materials and more broadly of historical painting techniques, artists' practices and the paint stratigraphy. Through a series of case studies, this paper demonstrates how a detailed knowledge of historic painting materials and techniques, based on study of documentary sources and archives of materials-based evidence from the analysis of paint cross-sections—both from the paintings being studied and related works—aids and enriches interpretation of XRF element maps of black paints. While samples are invaluable in understanding exactly how—and with what materials—such regions were painted, they are not always representative and scanning XRF may be of complementary benefit in providing a more holistic view of pigment distribution. The examples presented range from the fifteenth to the seventeenth century from both Northern Europe and Italy.

中文翻译：

---

黑暗中观察：解释与黑色涂料相关的 X 射线荧光元素分布图的挑战

在架上绘画的保存过程中，黑色窗帘或深色背景往往难以处理和理解其状况。尽管古代大师画作中的大多数黑色颜料本质上并不含有高原子序数元素，但对黑色颜料的研究是国家美术馆 X 射线荧光 (XRF) 扫描的主要用途和最有用的应用之一。作为一种视觉工具，黑色涂料的 XRF 元素分布图可用于评估覆盖范围或下面任何幸存原始涂料的状况，并揭示原始模型。然而，解释 XRF 元素图可能具有挑战性。重要的是不仅要考虑黑色或深色颜料的主要成分，但要了解其他可能的相关材料以及更广泛的历史绘画技巧、艺术家的实践和绘画地层学。通过一系列案例研究，本文展示了如何通过对文献来源和基于材料的证据档案的研究，通过对油漆横截面的分析来了解历史绘画材料和技术的详细知识——包括正在研究的绘画和相关工作——帮助和丰富对黑色涂料 XRF 元素图的解释。虽然样本对于准确了解这些区域是如何绘制以及使用什么材料绘制的非常有价值，但它们并不总是具有代表性，扫描 XRF 可能在提供更全面的颜料分布视图方面具有互补优势。