Abstract Although the solvent removal of unwanted layers (e.g. aged varnishes, overpaints, oxalate patinas, dirt) from easel paintings is one of the most frequently performed restoration treatments, it is questioned regarding its controllability and safety to the artwork. There is thus a need for developing suited diagnostic methodologies able to inform restorers on the chemical, optical and morphological effects of cleaning. To this aim, we have explored the possibility of complementary use of Optical Coherent Tomography (OCT) and reflection FTIR. On the one hand, the OCT technique provides cross-sectional images with varnish layers visible and thus permits for measurement of their thicknesses. Combining many cross-sections into 3D data provides insight into the varnish thickness distribution over a given area of the paintings. On the other hand, reflection FTIR allows for a chemical characterization of the surface compounds revealing the nature of the varnish and monitoring its removal. Artificially aged model samples and two historical paintings were investigated at different steps of solvent cleaning tests and the results of the two techniques compared highlighting the benefits of their combined exploitation.

中文翻译：

---

光学相干断层扫描 (OCT) 和反射 FTIR 光谱的互补使用，用于原位非侵入性监测架上绘画的清漆去除

摘要 虽然溶剂去除画架绘画中不需要的层（例如老化的清漆、上漆、草酸盐古色、污垢）是最常进行的修复处理之一，但其对艺术品的可控性和安全性受到质疑。因此，需要开发合适的诊断方法，能够告知修复人员清洁的化学、光学和形态效应。为此，我们探索了光学相干断层扫描 (OCT) 和反射 FTIR 互补使用的可能性。一方面，OCT 技术提供具有可见清漆层的横截面图像，从而允许测量它们的厚度。将许多横截面结合到 3D 数据中，可以深入了解绘画给定区域上的清漆厚度分布。另一方面，反射 FTIR 允许对表面化合物进行化学表征，揭示清漆的性质并监测其去除情况。在溶剂清洁测试的不同步骤中对人工老化的模型样品和两幅历史绘画进行了研究，比较了两种技术的结果，突出了它们组合开发的好处。