St. John the Baptist in the Wilderness, commissioned for the private chapel of Genoese banker. Ottavio Costa in 1602/3 and now in the collection of the Nelson-Atkins Museum of Art (#52-25), provides an important opportunity to understand Caravaggio's use of materials from one of his best-preserved paintings. macro-X-ray fluorescence (MA-XRF) elemental mapping has now been used to build upon a 2016 stratigraphic study of the palette employing optical and UV fluorescence microscopies, scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDS), Raman spectroscopy, and polarized light microscopy. The combined results of these methods clarify aspects of the iconography that have previously been obscure and expand our understanding of the roles of the various pigments. The roles for copper-based pigments are surprisingly diverse for a painting with few obvious green and blue passages, in which many greens are based on terraverte. Darkening of the foliage adjacent to the figure of St. John has long posed interpretive difficulties, due to poor legibility of the plants depicted there. The foliage has been clarified by the results of MA-XRF mapping, which distinguish the plant species by the palette choices involved in their depiction. Copper pigments play a fundamental role in Caravaggio's work, shading and modulating complementary colors with the additional practical benefit of playing a siccative role in paints that would otherwise dry poorly. MA-XRF mapping has also revealed a role for copper pigment used to lay out the composition that was not apparent through radiography or infrared imaging methods.

中文翻译：

---

卡拉瓦乔的铜

荒野中的施洗者圣约翰，委托为热那亚银行家的私人教堂建造。奥塔维奥·科斯塔 (Ottavio Costa) 创作于 1602 年 3 月，现已收藏于纳尔逊-阿特金斯艺术博物馆 (#52-25)，为了解卡拉瓦乔如何使用他保存最完好的画作之一中的材料提供了一个重要的机会。宏观 X 射线荧光 (MA-XRF) 元素测绘现已用于建立 2016 年调色板地层学研究，采用光学和紫外荧光显微镜、扫描电子显微镜-能量色散 X 射线光谱 (SEM-EDS)、拉曼光谱和偏光显微镜。这些方法的综合结果澄清了以前模糊的图像学方面，并扩展了我们对各种颜料作用的理解。对于一幅几乎没有明显绿色和蓝色通道的绘画来说，铜基颜料的作用令人惊讶地多样化，其中许多绿色都是基于 Terraverte 的。由于那里描绘的植物的可读性较差，圣约翰雕像附近的树叶变暗长期以来一直给解释带来困难。MA-XRF 绘图的结果已阐明了树叶，该绘图通过描绘植物种类时涉及的调色板选择来区分植物种类。铜颜料在卡拉瓦乔的作品中发挥着重要作用，它可以遮蔽和调节互补色，并具有在油漆中发挥干燥作用的额外实际好处，否则油漆会干燥不良。MA-XRF 绘图还揭示了铜颜料用于布置成分的作用，而通过射线照相或红外成像方法并不明显。