The process of leafing gold into a wooden picture frame begins with a coat of lacquer to seal the wood. Then many layers of gesso, usually about 12, are applied with a soft bristle brush. Each coat should be allowed to dry overnight and smooth with fine sandpaper before applying the next coat.
After all the layers of gesso have been applied, several layers of pigmented clays, called boles, are applied to the surface. The clay layers provide additional cushioning for the gold leaf, and the pigment adds shine to the finished piece. Bowls come in different colors, including black, yellow, and red. The brightness provided by a black bolus base is popular in the United States, while yellow covered by red is more common in Europe. Rabbit fur glue is added to dry clay pigment to create a solution that is brushed onto the layered piece. The piece receives five or six layers of bole, and each must be allowed to dry overnight.
After the last coat of bole has dried, the piece is smoothed to a silky finish with 0000 steel wool. A gilding brush of denatured alcohol and distilled water is brushed onto the frame, and a sheet of gold leaf of 24 carats is carefully placed in the piece. The gold leaf is gently rubbed into place with a soft bristle brush and allowed to dry. After drying overnight, the surface of the gold leaf is reduced with an agate-tipped polisher.
