The two stained glass panels that make up this image depict the birth of the Virgin. It is an intimate scene, showing the infant Mary at the centre standing on her mother’s bed – she is clearly a well developed child so soon after her birth! Saint Anne (also Anna or Hannah), her mother, is sitting up in the splendid curtained bed which is covered by a vibrant red blanket. An elderly woman reaches out to take the child; this may be a servant or perhaps the grandmother. In the foreground is another woman washing white cloths. She is referred to in the catalogue as a midwife¹.
Every time I look at this window I am distracted by the many repair leads; there are about 83 of them and they have been added over the years to secure and disguise glass that was broken. The area worst affected is in the beautiful red blanket and the face of the midwife, where the repair leads are so dense that they disguise the details of the paintwork and the intricacy of the design.
The damage in this area of the window was most likely caused by the impact of a thrown stone (or a similar object) as the breaks in the glass radiate from a central point. The only way that restorers in the past were able to repair such damage was to insert lead cames to bring the broken glass pieces back together. They used H-section leads with 1-2 mm cores and to accommodate the lead without making the whole area bigger the restorer had to take a little bit away from each glass piece (the equivalent of the added core).
Today we have sophisticated adhesives that can be used to bond broken glass pieces. There are many different types and some are formulated to match the properties of glass very closely. They can be tinted with pigments to match the colour of the glass and a skilled conservator can achieve an almost invisible repair. So in order to restore the area above, a conservator will carefully remove all the repair leads (which will be kept as samples and for analysis). A tinted resin is then injected into the spaces left by the lead. Once it is cured, the glass piece appears intact again.
It is a very time consuming process and it can be complicated – especially when dealing with such a complex break as in this window – but the outcome can be very successful and it can help to restore the image.
Before embarking on the mission to improve the visual impact of the panel and to make it easier to read, there are some issues that should be considered.
- What are we aiming to preserve? Are we mainly concerned about the image and the painted details or are we also interested in using the object to tell stories about our history? For instance, the complex lead repair is possibly the result of an attack on religious imagery during the reformation and witness to why so much of our stained glass heritage was destroyed and lost during that period. Is it worth preserving that aspect to better illustrate our history?
- As an object and piece of our heritage this window is as authentic as it will ever be and all marks on it including the repair leads and even the dirt are witness of its history. No amount of restoration will ever bring it closer to that state of authenticity. In this context it should also be noted that the window has been restored many times in the past and we cannot hope to ever return it fully to its “former glory”.
There are also some questions about practicalities and resources that need to be considered before we decide on the most appropriate conservation treatment:
- The lead repairs that are currently holding the glass together have probably been there for 142 years and they will last for at least that much time again provided the stained glass window is well cared for, kept in a stable environment and handled and moved as little as possible.
- A repair using an epoxy resin is said to last for as much as 80+ years but as this kind of product has only been in use since the 1970’s no one can actually confirm that. We have examples of epoxy repairs that were carried out 35 years ago and some of them are definitively failing. So we will also have to consider the cost implications of having to renew all these repairs in the future.
¹ Stained and Painted Glass Burrell Collection, 1965
The Corporation of the City of Glasgow written by William Wells