Abstract As part of a larger research aiming to develop analytical approaches to characterise gilt leather constitutive materials and identify material markers for their attribution, this paper focuses on the organic layers applied on the silver leaves: the gold varnish and the protective layer. Ancient gilt leather varnish recipes were first analysed and compared by ATR-FTIR and Py-GCMS to try to define markers allowing varnish discrimination. The research demonstrates that the two techniques cannot separate varnish recipes based on recipe-specific compounds present in minor concentration, but are sensitive to the variation in the oil-resin ratio. Therefore, quantification of the oil-resin proportion should be considered to help with the decor provenance attribution, as long as the gilt leather has not be lubricated. More importantly, the paper assessed the potential of infrared reflectance spectroscopy as a non-invasive analytical technique to characterise the organic layers applied on the silver leaves. Thanks to the metal leaf that acts as a mirror, infrared reflectance spectroscopy allows collection of high quality reflection-absorption spectra of the gold varnish and the protective layer in gilt leather. In the corpus of historical decors analysed, reflectance FTIR confirmed the presence of an oil-resin varnish in all gilt areas, and revealed, for the first time, the use of a protein compound as a protective layer in the silvered areas, as well as in some gilt areas. In the silvered area, different practices are evidenced, consequently a larger corpus of silvered gilt leather decor should be investigated to determine if these differences can be related to geographical practices.

中文翻译：

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红外反射吸收光谱法对烫金皮金漆及保护层的无创分析

摘要 作为旨在开发分析方法来表征镀金皮革构成材料并确定其属性的材料标记的更大研究的一部分，本文重点介绍了应用于银叶的有机层：金漆和保护层。古代镀金皮革清漆配方首先通过 ATR-FTIR 和 Py-GCMS 进行分析和比较，以尝试定义允许区分清漆的标记。研究表明，这两种技术无法根据配方特定化合物以微量浓度来分离清漆配方，但对油树脂比的变化很敏感。因此，只要未润滑镀金皮革，就应考虑对油树脂比例进行量化，以帮助确定装饰来源。更重要的是，该论文评估了红外反射光谱作为一种非侵入性分析技术来表征应用在银叶上的有机层的潜力。由于金属箔充当镜子，红外反射光谱可以收集金色清漆和镀金皮革保护层的高质量反射吸收光谱。在分析的历史花色语料库中，反射 FTIR 证实了所有镀金区域都存在树脂清漆，并首次揭示了使用蛋白质化合物作为镀银区域的保护层，以及在一些镀金地区。在镀银区，不同的做法得到证明，