Laser cleaning of stained glass windows – Final results of a research project

Abstract Based on two independent feasibility studies in Germany (1992–1995), a research project “Laser cleaning of stained glass windows” was launched in 1997 with the aim to facilitate systematic investigations within an interdisciplinary co-operation. This paper will give an overview on the final results of the 3 years project. A prototype laser cleaning station was constructed, using an Excimer-laser operating at 248 nm. The impact of the laser radiation was examined on model substrates to define alteration thresholds and ablation thresholds for all relevant materials involved. A description of the resulting effects of the laser-substrate interactions will be given for glasses with different compositions and colours, for corrosion crusts and polymer coatings. As the ablation process is not self-limiting for these types of materials, different sensoring systems were evaluated. The results obtained from cleaning experiments on selected originals will be discussed to demonstrate the possibilities and limitations for the application of lasers in stained glass restoration.