From a press release by Sally Austin, Education Officer at the Stained Glass Museum, Ely Cathedral:

"Glass muffs and lead calmes may not be the stuff of everyday life, but for over a thousand years these have been key components of stained glass window making. Incredibly, only one furnace survives in the UK where blowers continue to create original glass 'muffs,' or large bubbles which are flattened out into raw glass, and only a handful of places remain where lead calmes are still cast - the spidery jointing that bring together the whole glass picture. Before it is too late, The Stained Glass Museum, itself unique in Britain, wants to capture on film the rare medieval technology that's still used today in the art of stained glass. In doing so we will be helping to preserve an understanding of traditional and ancient skills, crucial for the making of traditional stained glass windows.

At the Museum our many visitors are fascinated not only by seeing stained glass at close-quarters but also in learning about the techniques involved in its creation. We want to further increase the appreciation and enjoyment of visitors of all ages by making some short films that will take the viewer through the processes involved in every stage of glass-making - from a grain of sand to a finished panel of stained glass."