Study of degradation of CdSSe pigments employed by modern artists

The project began with the study of the painting ‘Il quarto stato’ by the Italian divisionist painter Giovanni Pellizza da Volpedo. The study of the painted materials is important to obtain information on the painting process, the material's provenance, and the production technology, or to observe and prevent the degradation process. In this project, we propose to study with XAS a corpus of seven CdS1-xSex pigments produced with historical techniques and bound with four historical and modern binders, before and after artificial aging. The aim is to employ Cd K- and L3-edges, and Se and S K-edges, to observe and quantify structural changes in the pigment-binder systems due to photochemical alterations. This information will give deeper insights into the degradation processes occurring in these materials as observed in many paintings of the XIX and XX centuries, helping to better preserve these artifacts.

本项目始于对意大利分色主义画家（divisionist painter）乔瓦尼·佩利扎·达·沃尔佩多的画作《第四阶级》（Il quarto stato）的研究。对绘画材料的研究至关重要，可获取有关绘画工艺、材料来源与生产技术的信息，亦可观察并预防降解过程。本项目拟采用X射线吸收光谱（X-ray Absorption Spectroscopy, XAS）研究一组样本：该组样本包含7种以历史工艺制备、并与4种历史及现代粘合剂结合的硫化镉硒颜料（CdS1-xSex pigments），研究将覆盖其人工老化前后的状态。研究旨在利用镉的K边与L3边、以及硒和硫的K边，观察并量化颜料-粘合剂体系因光化学变化而产生的结构改变。这些信息将为理解19世纪与20世纪众多绘画中此类材料的降解过程提供更深入的视角，助力更好地保护这些文物。