Since 1972, The Cathedral Studios have designed and made a wide range of traditional and modern stained glass windows for both churches and personal clients. Their expertise and knowledge have been used to protect some of the finest and most sacred windows in the British Isles; the Studio’s latest project has seen the team travel further afield – assisting, advising and training the conservation team at Uppsala Cathedral in Sweden.
Consecrated in 1435, Uppsala is Scandinavia’s largest church. The Great South Transept Window of the Cathedral dates back to 1892. It was designed by architect and artist Agi Lindegren, and made by the Swedish Glass Painting AB in Gothenburg . It is the only one of the Cathedral’s windows with a narrative content and is probably the largest stained glass window in Sweden, and as such of great importance to the nation.
The window was one of the first products by Swedish Glass Painting AB, and the firm’s inexperience may be a contributing factor in the rapid deterioration of the window’s painted decoration. Paint loss was observed by the 1920s and this has continued to the present day. Since installation in 1892, the window has lost possibly more than 50% of its original painted detail. It is a testament to Lindegren’s artistic strength that, even in their faded state, the legibility of the depicted scenes is hardly diminished. The window continues to be a very important aesthetic and theologically significant part of Uppsala Cathedral’s fabric.
In recognition of this fact, Uppsala Cathedral decided to investigate ways to preserve the South Window through the introduction of protective glazing. In April 2012, a delegation from Uppsala Cathedral visited the stained glass conservation department of Canterbury Cathedral for a fact finding mission. Canterbury Cathedral is one of the foremost places in Europe where protective glazing systems have been developed. This was followed by a visit by Leonie Seliger, Director of Stained Glass at Canterbury Cathedral, to Uppsala Cathedral in September 2012. Scaffolding on the inside of the window enabled a close inspection of the glass. As a result of this visit, the decision was made that of the 105 individual stained glass panels that make up the 14 metre high window, six would be selected for the trials. They were removed and shipped to Canterbury to undergo further tests and treatment trials.
The aim of these tests is to develop a conservation methodology for the entire window. The actual conservation of the remaining glass will be carried out in Uppsala by a Swedish conservator, who will come to Canterbury for training before commencing work on the window in Uppsala.
Once the six panels had arrived in Canterbury, the Conservation team undertook a detailed inspection of the glass; there are a number of different issues that the team will deal with as part of the treatment. First, it is necessary to find a safe way to clean the internal surface of the glass, which is currently covered in a dense layer of soot. The soot may (through its potential acid content) be a contributing factor in the decay of the painted decoration on the inside of the window. The glass paint has lost a great deal of detail already, and the remainder is in a very fragile state. The source of the soot is still to be investigated: candles, the heating system, and previous lighting systems are all on the list of possible suspects. Our colleagues at the Cathedral in Uppsala are working on identifying the source of the pollution with a view to stop future erosion.
Previous repairs to the window have included the application of resins to mend fractures. These resins have now decayed and become discoloured, so their removal and replacement with a more durable resin is also on the list of repairs. Moreover, in the past, some glass pieces were replaced with very unsuitable unpainted glass. The Studio will create a number of different versions of replicas to illustrate how one might replace these crude stopgaps with more suitable insertions. An investigation will also be carried out on the structural stability of the lead matrix, along with repairs to unstable parts. And finally, a protective glazing system will be developed and installed to safeguard the future of this important window.
The result of this exercise will be a framework of techniques that will enable conservators in Sweden to undertake the conservation of the whole window on site in Uppsala.
We look forward to keeping you up to date on this project. If you would like to find out more about the external projects carried out by the team, please click here to view the Cathedral’s Studio’s website.