This paper discusses the spectral sensitivity of the discoloration of historical rag paper simultaneously affected by Relative Humidity (RH) and Oxygen concentration [O₂] in the ambient environment. Sacrificial samples were degraded using narrowband radiation sources centred at 450 nm, 525 nm, and 625 nm in combinations of RH and [O₂] at two levels: 0% [O₂] and 70% RH, 21% [O₂] and 70% RH, 0% [O₂] and 20% RH, and 21% [O₂] and 20% RH. Diffuse reflectance was measured before and during the degradation experimental runs. Consistent qualitative results were obtained for the change in reflectance and the change in tristimulus total color change in CIELAB color space. In both cases, the increase of discoloration was modelled logarithmically over time. Among the three factors investigated in this research, wavelength of the radiation (Λ) was found to have the strongest effect. The radiation at 450 nm induced the most and fastest discoloration whereas the radiation at 625 nm induced the least and slowest discoloration. This spectral dependence was likely to be related to the photo energies at different wavelengths, but other factors were found to have played a role. Further analyses revealed that the main effects and the effects of the interactions between [O₂] and Λ and between RH and Λ on the discoloration of historical rag paper were statistically significant. It suggests that managing the spectral power distribution of the radiation source can be crucial in the collection management.

本文讨论了同时受周围环境中相对湿度 (RH) 和氧气浓度 [O ₂ ]影响的历史破布纸变色的光谱敏感性。牺牲样品使用集中在 450 nm、525 nm 和 625 nm 的窄带辐射源以 RH 和 [O ₂ ] 的组合在两个水平下降解：0% [O ₂ ] 和 70% RH、21% [O ₂ ] 和70% RH、0% [O ₂ ] 和 20% RH 和 21% [O ₂] 和 20% RH。在降解实验运行之前和期间测量漫反射率。对于 CIELAB 颜色空间中反射率的变化和三色总颜色变化的变化，获得了一致的定性结果。在这两种情况下，变色的增加都是随着时间的推移对数建模的。在本研究调查的三个因素中，发现辐射波长 (Λ) 具有最强的影响。450 nm 处的辐射引起最多和最快的变色，而 625 nm 处的辐射引起最少和最慢的变色。这种光谱依赖性可能与不同波长的光能有关，但发现其他因素也起作用。进一步的分析表明，[O₂ ]和Λ以及RH和Λ之间对历史破布纸的变色有统计学意义。这表明管理辐射源的光谱功率分布在收集管理中至关重要。