比黄金还珍贵的颜料，到底是怎么消失的？(3)

荷兰阿姆斯特丹大学的凯特琳·基恩解释说：“如果你观察一下群青的结构，就会发现它具有催化活性。因为群青是一种沸石，与催化剂类似，它的分子可通过降解粘合剂来产生光散射效应。”
Keune first had a hunch that ultramarine could be catalytically active in 2006 when she artificially aged various oil paints that contained different pigments but which had the same linseed oil binder. The paint containing ultramarine was the only one that crumbled（使破碎，成碎屑） and results showed that the binder had completely degraded（降解）.

2006年，基恩第一次有了这样的想法。当时，她老化了各种含有不同色素但含有相同亚麻籽油粘合剂的油画颜料。其中，含有群青的颜料是唯一一个破碎的样品。结果显示，群青色的粘合剂已经完全降解。
‘In the case of ultramarine, the “dull and flat”appearance is due to the degradation in the medium –the blue of the pigment is still there and the greyish appearance in the degraded ultramarine paint is part of the original paint,’ says Keune.