How long does it take to make a stained glass window in the Middle Ages?

Answer 1

This is a complicated question, actually. The time it took to make a window could depend on its size, complexity and detail. This would affect how long it took to plan out the piece, cut the glass, stain and paint detail, and assemble and finish the final product. Even mounting the window could take time extra time, depending on whether it was going into a ground-level window or a window several stories high in a cathedral wall.

The most time-consuming part of making stained glass windows in the middle ages was probably the step for painting and staining each piece of glass. If you compare the old stained glass windows to the windows made today, you'll notice much more fine painting on the glass - facial features, folds in robes, symbols, hands, etc.

You can't color (or "stain") glass like you'd paint a picture on paper. For example, whenever you see a beige, yellow or gold color in Medieval stained glass, you can be sure that color was produced by painting the glass with a silver-containing chemical, then firing the glass in an oven. The more times a piece was repeatedly painted and fired, the deeper this golden color would be in the final piece. Likewise, the black lines used in details on faces, etc, had to be fired too, just like the glaze is fired on pottery.

After the pieces were ready, they were assembled between strips of lead containing grooves on each side to hold the edges of glass. The area in the groove around the edge of the glass was then packed with a putty - usually a mixture of linseed oil and lead oxide, to give the window room to stretch and move as the glass and lead got hot and cold over the years. The lead strips also had to be stained with patina - a chemical that turns it a black color. Finally, the assembled piece would often be large enough to require reinforcing bars added behind the window at intervals.

Since so many variables go into making a fine stained glass window, it's hard to estimate the time exactly. Still, the average single panel in an old cathedral would have taken well over 100 hours of labor, split up between however many people were working on it.