Abstract The presence of metal soaps is well documented in paintings originating from the 15th century onward, and in numerous cases, the soaps`formation is attributed to environmental factors, like relative humidity, light exposure and/or high temperature. Understanding the formation mechanism, involving effects of these particular factors during artwork`s realization, is crucial for the search of suitable conservation and preservation strategies. In the present study, the role of humidity on the formation of metal carboxylates and other secondary products in mixtures of lead-based pigments (i.e., minium, lead-tin yellow and lead white) with linseed oil was described within the experimental drying of model paints. Samples were exposed to various relative humidity conditions and the processes were monitored by Fourier-transform infrared spectroscopy (FTIR) and powder X-ray diffraction (XRD) involving both the hourly measurements for the monitoring of immediate processes and long-term (up to two months) monitoring to evaluate secondary changes. The acquired data clearly demonstrated the influence that the different levels of humidity may have on the formation of lead carboxylates during the painting's drying. The selected methods were efficient in the reaction monitoring and provided new insights leading to a better understanding of factors affecting the metal soaps' formation in paints.

中文翻译：

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模型涂料中金属皂形成的初始阶段：湿度的作用

摘要 金属皂的存在在 15 世纪以后的绘画中已有详细记载，在许多情况下，皂的形成归因于环境因素，如相对湿度、光照和/或高温。了解形成机制，包括这些特定因素在艺术品实现过程中的影响，对于寻找合适的保护和保存策略至关重要。在本研究中，在模型的实验干燥过程中，描述了湿度对铅基颜料（即，minium、铅锡黄和铅白）与亚麻籽油混合物中金属羧酸盐和其他副产物形成的作用。油漆。样品暴露在各种相对湿度条件下，并通过傅里叶变换红外光谱 (FTIR) 和粉末 X 射线衍射 (XRD) 监测过程，包括每小时测量以监测即时过程和长期（最多两个月）监测以评估次要变化。获得的数据清楚地表明，不同的湿度水平可能对油漆干燥过程中羧酸铅的形成产生影响。所选方法在反应监测方面是有效的，并提供了新的见解，从而更好地了解影响油漆中金属皂形成的因素。