The plasterers take casts of the Cathedral’s sculpture and ornament, which the carvers use to recreate the building’s historic decoration. These casts also help us to make a record of all the cathedral’s different sculptures. This has been especially important since 1983, when parts of the Archbishop Palace were destroyed by fire, including the original plaster cast collection.
Silicon moulding methods are used to make these casts. However, silicon moulding of external stone surfaces can have a detrimental effect upon longevity. Methods to limit this eventuality have been developed by the cathedral plasterers.
The plasterers have since 2017, been utilising photogeometric processes and software in parallel to their casting work. 3-D scanning is especially useful in instances of highly eroded or weakened surfaces which otherwise would be in danger of being destroyed by traditional methods for mould making. This method also gives us the possibility to connect information about the objects to other databases and virtual platforms.
The plaster workshop is responsible for the production of souvenirs for sale in the cathedral shop. These consist of painted plaster copies of the cathedral’s ornamental decoration. Some copies are direct casts and others are finely modelled, downscaled reproductions. There have also been modelled some new figurines in the plaster workshop for sale in the shop.
The workshop is in the process of building up a collection of fine plaster ceiling roses. These are often in a bad condition when found, with thick layers of paint and broken or missing parts. The plasterers restore these ornaments to their original condition and make new silicon moulds of them. These “new” copies can then be installed into private houses and apartments.
In addition to these tasks, the plaster workshop is involved with external projects, not related to the documentation and restoration of the cathedral. These projects have included large-scale mould making (for example, the making of moulds for artists and the moulding of existing public sculpture as part of a restoration process) and the creation of new ornamental and architectural objects for use in homes and as theatrical scenery. Many external projects have been concerned with restoration of ceilings in old buildings. Over the past 10 years, the plasterers have carried out work on several ceilings from the eighteenth, nineteenth and twentieth centuries. Typical examples of this work is the repair of cracked and loose surfaces, repair and renewal of profiles and cornicing, and the securing and consolidating of fragile plasterwork.