ABSTRACT

Warm yellow facades, popular for centuries and throughout the world, were typically painted with ochre but could be copperas-based. Copperas is iron sulphate mixed with lime, and oxidation produces a golden colour. Usually, the methods are distinguished by appearance. Knowing the original painting method is critical for historical context and conservation, so the research program evaluated characterization methods to supplement visual assessment. Mock-up lime plaster boards were painted with copperas and yellow ochre paints. XRF, optical microscopy, SEM, EDS and XRD were conducted on surface samples, cross sections, and particles. Results show plaster staining for copperas solutions, optical differences of paint particles in crossed polars, and differences in surface morphology of finishes and pigment grains. The experimental program revealed how strongly the preparation of materials and application technique impacts the appearance and properties of the resulting finishes.

摘要

温暖的黄色外墙流行了几个世纪并在世界各地流行，通常涂有赭石，但也可能是铜色的。Copperas 是与石灰混合的硫酸铁，氧化会产生金色。通常，这些方法通过外观来区分。了解原始绘画方法对于历史背景和保护至关重要，因此研究计划评估了表征方法以补充视觉评估。模拟石灰石膏板涂有铜色和黄赭色涂料。对表面样品、横截面和颗粒进行 XRF、光学显微镜、SEM、EDS 和 XRD 分析。结果显示了铜溶液的石膏染色、交叉极性中油漆颗粒的光学差异以及饰面和颜料颗粒的表面形态差异。