Metal soaps are formed in paint layers thorough the reaction of metal ions of pigments and fatty acids of organic binders. In this study, micro-ATR-FTIR spectroscopic imaging was used to analyse the formation of lead soaps in oil-based paint layers in relation to their exposure to moisture sources. The investigations were carried out on authentic samples of complex stratigraphies from cold painted terracotta statues (Sacred Mount, Varallo, UNESCO) and different IR-active lead white pigments, organic materials, and lead soaps were discriminated. The saponification of selected paint layers was correlated to the conservation history, the manufacturing technique, and the build-up of layers. The presence of hydrophilic layers within the stratigraphy and their role as a further water source are discussed. Furthermore, the modifications experienced by lead-based pigments from the core of an intact grain of pigment towards the newly formed decay phases were investigated via a novel approach based on shift of the peak for the corresponding spectral bands and their integrated absorbance in the ATR-FTIR spectra. Qualitative information on the spatial distribution from the chemical images was combined with quantitative information on the peak shift to evaluate the different manufacture (lead carbonate, basic lead carbonate) or the extent of decay undergone by the lead-based pigments as a function of their grain size, contiguous layers, and moisture source. Similar results, having a high impact on heritage science and analytical chemistry, allow developing up-to-date conservation strategies by connecting an advanced knowledge of the materials to the social and conservation history of artefacts.

金属皂是通过颜料中的金属离子与有机粘合剂的脂肪酸反应而形成的。在这项研究中，使用微型ATR-FTIR光谱成像来分析铅基皂在油基漆层中与暴露于湿气源之间的关系。调查是对来自冷漆兵马俑雕像（圣山，瓦拉洛，联合国教科文组织）的复杂地层的真实样本进行的，并区分了各种红外活性铅白色颜料，有机材料和铅皂。所选涂料层的皂化与保存历史，制造技术和层积相关。讨论了地层中亲水层的存在及其作为其他水源的作用。此外，通过基于相应光谱带峰的移动及其在ATR-FTIR光谱中的积分吸光度的新颖方法，研究了铅基颜料从完整颜料颗粒的核心向新形成的衰减相经历的修饰。将化学图像中有关空间分布的定性信息与峰移动中的定量信息相结合，以评估不同的制造方式（碳酸铅，碱性碳酸铅）或铅基颜料根据其晶粒而发生的衰减程度大小，连续的层和湿气源。相似的结果对遗产科学和分析化学有很大的影响，因此可以开发 碱式碳酸铅）或铅基颜料根据其晶粒大小，连续层和湿气源而衰减的程度。相似的结果对遗产科学和分析化学有很大的影响，因此可以开发 碱式碳酸铅）或铅基颜料根据其晶粒大小，连续层和湿气源而衰减的程度。相似的结果对遗产科学和分析化学有很大的影响，因此可以开发通过将先进的材料知识与手工艺品的社会和保护历史联系起来，制定最新的保护策略。