Abstract A preliminary study into the reduction and removal of naturally aged varnishes, aimed at collating observations to encourage further study of the cleaning of paintings with intractable, difficult to remove coatings, is presented in this article. Er:YAG laser cleaning trials with dry laser exposures followed by solvent removal of natural resin varnishes were conducted on a naturally aged test panel, and an expendable nineteenth-century oil painting. Surfaces were examined with normal and ultraviolet light, a headband magnifier, and low-power digital microscopy, videography and colorimetry. Standard solvent cleaning tests were first carried out, followed by a two-step cleaning protocol where Er:YAG irradiation of the coating was followed by solvent cleaning, the laser being used to promote a weakening or disaggregation of the topmost portion of the layer or layers of varnish. The aim was to assess the laser cleaning outcomes conservators might expect on ‘real’ as well as mocked-up surfaces; results are presented from one of each. Cleaned areas of paint were also directly exposed to Er:YAG irradiation to determine a safe fluence with observations limited to relatively low magnifications. Overall these efforts inform the risks and contribute to the development and the safe use of this novel cleaning method.

中文翻译：

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在使用溶剂的两步清洁过程中，使用Er：YAG激光减少和去除漆面自然老化清漆的初步研究

摘要本文对减少和去除自然老化的清漆进行了初步研究，旨在整理观察结果，以鼓励进一步研究难以处理且难以去除的涂料的清洁。在自然老化的测试板上进行了Er：YAG激光清洁试验，包括干激光暴露，然后去除溶剂，去除天然树脂清漆，并在19世纪使用了昂贵的油画。用普通和紫外线，头带放大镜以及低功率数字显微镜，摄像和比色法检查表面。首先执行标准溶剂清洁测试，然后进行两步清洁方案，其中用Er：YAG照射涂层，然后进行溶剂清洁，激光用于促进一层或多层清漆的最顶层的弱化或分解。目的是评估保护者在“真实”和模拟表面上可能期望的激光清洁效果；结果来自每个。清洁后的油漆区域也直接暴露在Er：YAG辐射下，以确定安全通量，并且观察结果仅限于相对较低的放大倍率。总的来说，这些努力为这种风险提供了信息，并为这种新型清洁方法的开发和安全使用做出了贡献。用YAG辐照确定安全通量，而观察结果仅限于相对较低的放大倍数。总体而言，这些努力为这种风险提供了信息，并为这种新型清洁方法的开发和安全使用做出了贡献。用YAG辐照确定安全通量，而观察结果仅限于相对较低的放大倍数。总体而言，这些努力为这种风险提供了信息，并为这种新型清洁方法的开发和安全使用做出了贡献。