The glass needs to be lit from behind
during the painting process to simulate what it will look like when installed
as a window. To paint large panels, Leap attaches the individual pieces of glass
to a larger piece of plate glass, a process called "waxing up." The glass can
then be painted by placing it on a glass easel in front of a light source.
The Centaur was made by painting
black pigment over colored pieces of glass. This is the most basic technique
of glass painting and it is identical to the way church windows were made as
early as the 12th century. The faces on the light box expand on this technique.
Black pigment was painted onto clear glass and fired. Afterwards, colored pigments
were applied and then fired again. The application of colored pigments is called
enameling. It came into use during the 15th century. Leap's animals are frequently
painted like the sleeping chipmunk, lower left. They are completely rendered
in black pigment before color is applied.
Most of the glass Leap uses for his
windows is mouth-blown and colored all the way through. For detailed areas, he
frequently uses "flashed" or "overlay" glass. This type is characterized by having
a thin layer of colored glass only on one surface. The color can be removed by
sandblasting or acid etching.
The pigments used for painting on glass
are made from glass frit and metal oxides. They are sold in powder form and can
be mixed with different media to achieve different effects. Leap mixes black pigment
with an oil, and paints with a long tapered brush called a tracing brush to create
the line work in his pieces. Tonalities are created by mixing the same pigment
with water and applying it with a badger hair blender brush or an airbrush.
This mannequin holds a fine pointed
tracing brush made from fitch hair, and a badger hair blender brush. The blender
is used to remove brush strokes when laying down a broad application of paint
called a matt. The tonal details in glass painting are achieved by skillfully
removing pigment from the dark field of the matt. A variety of stiff brushes and
quills are used for this purpose.
The pattern for a stained glass window
is called a cartoon. It contains the drawing of the details that will be painted
onto the glass as well as the outline of the individual pieces of glass that make
up the panel. Colored pieces of glass are cut to shape with a glass cutter using
the pattern as a guide.
The image in this paperweight was painted
with high temperature glass pigments on a small glass sphere. The sphere was then
cased with more glass by dipping it into the furnace at the glass factory.
After a layer of pigment is applied
to the glass creating a matt, it is allowed to dry. A variety of stiff brushes
and quills are then used to scratch away pigment from the matt to create details
on the glass. The pigment can be manipulated in this manner because it does not
become permanent until it is fired in the kiln.
After the glass is painted and fired,
it is assembled using strips of lead called cames. Lead cames have a groove on
each side into which the glass fits. Solder is used to join the leads where they