ABSTRACT

To understand the degradation behaviour of rolled hanging scrolls for future conservation treatments, we evaluated the degradation–position profiles of naturally aged hanging scrolls and their model samples, which were subjected to different storage conditions. For the sample immersed in a CuSO₄・5H₂O solution and rolled around a glass rod, accelerated ageing using the open method (80°C, 65% RH) revealed a tendency of lower pH and higher discolouration towards the central positions, where rolling caused the most tightness. However, no clear tendencies were observed for the concentration variations of organic acids. The degradation effects of the organic acids emitted from the paulownia wooden box were also examined using the sealed tube method by enclosing the rolled painting paper and acidic paper containing organic acids together in a glass tube. Large amounts of oxalic and formic acids were detected at the periphery and scant migration of the organic acids was observed towards the centre, thus indicating that the central positions of the painting paper were less susceptible to the influence of the organic acids emitted from the external environment. By contrast, glycolic acid diffused towards the centre. The analysis of two naturally aged hanging scrolls showed different degradation behaviours. One sample, stored open in the rolled state, showed severe discolouration with the naked eye at the outermost back surface of the scroll. This was possibly associated with the large amount of sulfate ions originating from the external atmosphere, which kept the pH lower and increased discolouration towards the peripheral positions of the painting paper. For the sample stored in a paulownia wooden box, discolouration was not observed with the naked eye at the outermost back surface of the scroll, although lower pH and higher discolouration were observed towards the central positions.

摘要

为了了解用于未来保护处理的卷轴的退化行为，我们评估了自然老化的挂轴及其模型样本在不同存储条件下的退化位置曲线。对于浸泡在 CuSO ₄・5H _{2中的样品}O 溶液并绕着玻璃棒滚动，使用开放法（80°C，65% RH）加速老化显示出朝向中心位置的较低 pH 值和较高变色的趋势，滚动导致最紧密。然而，没有观察到有机酸浓度变化的明显趋势。还使用密封管法检查了泡桐木箱排放的有机酸的降解效果，方法是将卷起的画纸和含有机酸的酸性纸一起装入玻璃管中。在外围检测到大量的草酸和甲酸，并且观察到有机酸向中心的迁移很少，从而说明画纸的中心位置不易受到外界环境释放的有机酸的影响。相比之下，乙醇酸向中心扩散。对两幅自然老化的挂轴的分析显示出不同的退化行为。一个样品，以卷起的状态打开存放，在卷轴的最外层后表面肉眼显示严重变色。这可能与来自外部大气的大量硫酸根离子有关，使 pH 值较低，并增加了画纸周边位置的变色。对于保存在泡桐木箱中的样品，在卷轴的最外表面用肉眼没有观察到变色，