Bole
Bole is a fine clay laid under gold leaf in water gilding. It gives the gold a soft, smooth bed that takes burnishing, and its colour passes through the leaf and warms its tone. Bole comes in red, yellow, and black, in a range of quantities, for panel icons and church work.
Bole is a fine, soft clay, and it is the layer water gilding stands on. It is laid in a few thin coats over the gesso, smoothed and polished, and the gold leaf settles onto the prepared surface. Burnishing with an agate presses the leaf into the soft clay beneath, and this is how gold reaches the deep, mirror shine that sets water gilding apart from every other technique.
The colour of the bole works together with the gold. The leaf is thin enough for the tone beneath to pass through it: red bole, the classic choice of iconography, warms the gold and gives it depth, yellow keeps the tone light and forgives the small gaps of the leaf, and black draws the gold toward the cool. In the haloes and grounds of panel icons, as on the large surfaces of a church, the bole sets the final character of the gilding.
Art & Colour carries bole in a range of colours and quantities, beside the gold leaf, gilding sizes, and the other materials of the icon workshop.