Christmas
Cover story Creating a stained glass window
After the nuns of Visitation Academy approved Lea Koesterers
scale watercolor of Visitation, the first step in creating the
window itself was selecting the glass.
Koesterer taped small samples of colored glass to a clear window
in her studio to test how well the variety of hues work together. Background
interference, white light from other windows and color saturation are some of
the factors that can make deeper shades of color appear almost black.
Following this selection process, Koesterer ordered German
hand-blown glass from an importer in San Francisco.
While the glass was on order, she spent two days at Visitation
Academy in spring 2000, enlarging the line drawing, known to artists as a
cartoon. Using school equipment, she projected the watercolor image onto a wall
at the windows actual size, 7 feet high by 14 feet wide, and traced it
onto paper.
In a trip to the fabricator of the windows sash, Koesterer
made templates of the outer dimensions of the opening. With these and the
cartoon in hand, she made the patterns for cutting each piece of glass and for
assembly.
Cutting the pieces out of sheets of glass is another stage of the
work calling for careful selection. Unlike machine-made glass, the handmade
glass that Koesterer used has great variation of hue even within a single
sheet. Where the glass is thicker, color saturation is greater.
Also at this stage, the figures hands and faces were painted
on and fired at over 1,100 degrees Fahrenheit.
After the glass is cut, it is assembled with leading and soldered
together. After one side was soldered, the entire window was turned over and
soldered on the other side. Because a stained glass window is extremely fragile
at this point, Koesterer used a board to raise the window to a vertical
position and then lower it on the same board to expose the other side for
soldering.
Next, the window was weatherproofed on both sides. Weatherproofing
material, besides adding protection from the elements, adds structural support
by filling in the air space between the glass and the lead.
In the final stages, a patina was added to the joints, making the
lead and solder the same dark hue. Reinforcing rods were added, so when the
window heats up in the sun and the lead gets softer, the rods keep the window
from buckling.
Finally, in September 2000, the window was installed.
-- Teresa Malcolm
National Catholic Reporter, December 21,
2001
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