Technology saves the Middle Ages: the cathedral is under laser treatment

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02/28/2023 14:09

Technology saves the Middle Ages: the cathedral is under laser treatment

The DBU supports the project to eliminate environmental damage

Halberstadt. Halberstadt Cathedral is clearly suffering from man-made environmental impacts – the blackening of the stones increases. For the first time in the field of monument protection, an application catalog for cleaning using laser technology is now being developed. The project of the Saxony-Anhalt Cultural Foundation is funded by the German Federal Environment Foundation (DBU) with approximately €125,000. This is not the first joint project on a cathedral of national importance in Halberstadt. The choir sculptures have already been saved with DBU funds and new restoration techniques.

Sulfur air pollution and climate change are damaging many structures in the area

Environmental impacts caused by humans caused great damage to the medieval cathedral. One reason: sulfur dioxide, which is mainly produced when burning sulfurous fuels such as coal, pollutes the air and starts the processes of damaging stone materials. “So-called acid rain leads, for example, to an imbalance in the conversion of lime into gypsum,” says Sibel Weiglt-Rösseler from the Saxony-Anhalt Cultural Foundation. According to the Federal Environment Agency (UBA), sulfur dioxide emissions have fallen by about 96 percent since 1990 – for example due to plant closures or technical retrofits in eastern German states, the use of sulfur-saving fuels and stricter requirements for exhaust gas cleaning in large combustion plants. . According to the UBA, coal use also declined between 2017 and 2020.

However, a critical challenge remains: “Increased humidity as a result of the climate crisis is exacerbating the existing damage from sulfur dioxide,” says Weiglt-Rösseler. According to her, this activates the existing sulfur and nitrogen salts and thus causes additional structural damage. “This is the case for many buildings in the area,” she says. Against this background, the Kulturstiftung Sachsen-Anhalt designed this exemplary research project in collaboration and for scientific and restoration support with graduate restorer and doctorate in art history Corinna Grimm-Remus and the Institute for Diagnostics and Conservation of Monuments in Saxony and Saxony-Anhalt (I don’t know).

DBU Secretary General Alexander Bond: “We are able to change something.”

The good news: “We can change something,” said DePew’s general secretary, Alexander Bond. In the case of sulfur dioxide emissions, this has already been achieved to a large extent. “Implementation of the 2015 Paris Climate Protection Agreement is important in order to stop global warming.” In addition, the damage caused must be compensated. “Restoring and preserving cultural assets of national importance is our responsibility,” says Bond. “Digital methods play a special role, and they should be easier to apply in practice.”

The first application catalog and setup of laser technology in the Monument area

Since the 1990s, “laser technology for surface cleaning has been established in archeology practice,” says Konstanz Fuhrmann, head of the Environmental Protection and Cultural Property Department at the DBU. According to restorers, it is recognized as a high-quality cleaning method in restoration science, especially due to the non-contact treatment. However, their use still takes a certain amount of time and requires specially trained personnel. Another challenge: instrument tuning parameters must be adapted to the various harmful phenomena and substances that are constantly present to achieve successful results. “This is where Halberstadt Cathedral comes into play,” says Formann. “It’s very interesting because it shows so many different damage patterns on the stone, which different laser applications can be tested as models.”

The DBU promoted the cleaning and color preservation of the choir sculptures

The laser project is not the first project supported by the German Federal Environment Foundation at Halberstadt Cathedral. The DBU has also funded the rescue of 14 colored 15th-century choir sculptures for the sum of €120,000. “The plaster used in the Middle Ages as part of the coating was not able to withstand the unfavorable climatic environment and the permanent microbiology,” says restorer and collaboration partner Corinna Grimm-Remus. “That’s why color copies come out.” In addition, according to her, the air containing sulfur dioxide and lack of care had a negative effect. Using sturgeon glue, silk and new restoration methods, it was possible to clean up the life-size figures and bring out their original colour. In collaboration with the Bauhaus University Weimar, remote-controlled drones helped with the documentation.

“We also want to carry out laser cleaning of the Gothic cathedrals in Halle and Magdeburg, which are also nationally important, in order to gain comprehensive experience with various base materials and contamination,” says Grimm-Remus.

additional information:

https://www.dbu.de/123artikel39654_2442.html Online press release

the pictures

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Choir statue of the Apostle Bartholomew in Halberstadt Cathedral before (left) and after restoration …

Corinna Grimm Reims

Features of this press release:

journalists
Cultural Studies, Art/Design, Environment/Ecology
nationally
Research/knowledge transfer
German