Glassy Bones

tap...tap...tap...tap....

It is late afternoon, and I am at my easel, designing a window. As I work, I find myself half-listening to the sounds of my assistant, Matthias, as he cuts glass in the workshop. The wheel of the cutter hisses across the glass, scoring the sheet. Next comes a series of rhythmic taps, which change pitch as the scored line deepens and becomes a crack. There is a pause and then the distinctive sound of the break: small pieces produce a short, high ping; larger sheets give off a low, resonant tone. If the break isn’t clean, there is the crunch of the grozing pliers, trimming the excess material. Finally, there is a quick scraping, to smooth any sharp edges.

Rather than distracting me, these sounds keep me connected with my craft - with the materials and techniques that eventually turn the drawing in front of me into glowing panels of color and light. The sounds also provide a link to the past. Closing my eyes, I can place myself in almost any century, for the sounds of a glass workshop then wouldn’t be much different from those I hear today.

This link to the tradition of stained glass is an important part of my work, and of my identity as an artist/craftsman. Early in my studies, I was fascinated by medieval windows. There is a unique quality about them that intrigued me then, and continues to inspire me. Through them, I feel a connection with the ideas and visions of my predecessors; I can begin to see the world as the creators of these windows saw it.

To connect with the past, the windows are often all we have. The men and women (yes, there were a few) who made medieval windows left almost no writing, and they themselves were rarely written about. If anyone it was the patrons, those footing the bill for the windows, who made it into the history books.

What little we know of medieval techniques and working practices comes from craftsman’s manuals, and from the regulations of the Guilds that controlled the profession. Unfortunately, no tools are known to have survived. The drawings and descriptions that still exist tell us that the tools and materials of the time, while similar in shape and function to ours today, were quite primitive. I am in awe of the beauty that was accomplished with those tools, in spite of all of the challenges of medieval life. The windows are a testament to the vision and persistence of the people who designed, painted and built them. Beyond the surface of the windows, beyond the figures and the colours we see, is an additional richness; a sum of the gifts of each capable hand that made them.

Another source of information on medieval glaziers and glass painters is the financial records of the time - account books, taxation records, bills, and the occasional contract. Frustratingly, many of the records that have come down to us are for windows that have long since disappeared; meanwhile, medieval windows that have survived the perilous journey through time don’t show up in any records.

One of the rare windows for which records still exist is the East window of York Minster. This window was completed in 1408 by a workshop under the direction of glass-painter John Thornton of Coventry. Rising 77 feet high by 32 feet wide, the window towers above the high altar in the church, providing a dazzling wall of light. The window is divided by theme into three main sections. In the tracery at the top are figures representing the whole company of Heaven. Below the tracery, in the main light, are twenty-seven panels portraying scenes from the Old Testament, and below these panels are eighty-one more that represent themes from Revelations. The records for this window show that it was built in just three years.

Assembling the puzzle pieces we have from craftsman’s manuals and financial records, we can perhaps imagine what a day in John Thornton’s stained glass workshop would be like...

It is just past daybreak when Thornton arrives in his workshop. It is mid-winter, and he has to make the most of the brief hours of daylight. His assistants already have a fire started in the forge, to warm the workshop and heat up the soldering irons, as Thornton uses the morning light to inspect the work of the day before. He checks it carefully, for he has had some trouble with the extra workers who he has had to hire for this commission, and the local Glazier’s Guild is strict in its efforts to maintain standards and to safeguard the reputation of the craftsmen of York. Fortunately, Thornton can count on his own apprentices to do good work; although they are of different ages, he has trained each of them since they were ten or twelve years old.

On this morning, as on every morning, John Thornton is feeling the pressure of his deadlines. Three years is a short time to create such a monumental window, and the progress of his work depends on many factors over which he has no control. His most important material, the glass, is also the one most vulnerable to problems. The primitive manufacturing conditions of the time can produce unacceptable variations and defects; and the only available transportation, carts on rutted roads, make broken pieces and late deliveries common events.

Putting aside his worries, Thornton gives his approval for the finished panels, and as they are removed and stored, one of the assistants begins to whitewash the glazing table in preparation for new panels. While he is waiting for the whitewash to dry, Thornton works at another table, putting the finishing touches on some painted figures. One of his more experienced apprentices has done most of the painting, but in accordance with his contract for the windows, Thornton alone will paint the faces and hands.

Those pieces that are ready for firing are arranged in iron trays, on a bed of dry quick-lime or ashes. In the meantime, the kiln is being heated up for the day’s firing. The small kiln is made of arched rods covered with clay and horse dung. Six hours from now, it will be hot enough to fire the painted glass. Once the firing is done, it will take 12 hours to cool, before it is ready for the next firing.

Pieces from the previous day’s firing are returned to the glazing table and leading up has begun. Thornton’s workshop, like most in that era, casts its own lead came by pouring molten lead into molds. Thornton checks the progress of the work and the supply of came before returning to the newly whitewashed table.

Now that the whitewash has dried, Thornton can begin to sketch out the full size design for the next panels on the fresh surface. As he works he uses letters to mark which colors are to be used. He also draws in the shading, painting and other details, for it is on this table that all of the cutting, painting and glazing will take place.

Meanwhile, on another table, one of the workers draws a hot iron rod along a cut line, and then dowses the score to crack the glass. Once the glass is broken, the edges are trimmed into shape with a grozing iron. This tool has a hook at each end, and with the hook the glazier “nibbles” the edges of the glass to bring it to its exact shape.

It’s a busy day in the workshop. Before Thornton can finish drawing out the new section, the light has begun to fade. He finishes a section of the design by lamplight, rubs his eyes, and goes to check the kiln. He makes a last check of the workshop, blows out the lamps, and shuts the door. Darkness shrouds the room, and Thornton walks home.

It seems a miracle to me that six hundred years later, we can still go and see Thornton’s window at York Minster. And in that window, I can see how close we still are to the craft practices that created it. Despite some modern improvements, we still use mostly hand tools, cut each piece of glass individually, and hold the leads in place with horseshoe nails as we build the panel. And John Thornton would have no trouble following most of the techniques we use. Our methods of painting, silver staining and firing are all based on techniques he used in the early 1400s.

Of course, we can’t really know what medieval craftsmen really thought and felt; but our common experience brings with it some degree of understanding. Certainly, they would have understood the vulnerability of their creations. Glass would shatter even as they worked on it, and they would be well aware of the hazards their creations would face. They would understand, even as we do now, that the creation of a stained glass window is, at its root, an act of optimism.