Bole is a specific type of clay used as a base for gold leaf in the water gilding technique. It is applied to the surface to be gilded which has previously been prepared with gesso. Bole allows the leaf to adhere to the surface over time and helps achieve a brighter finish to the gold in the burnishing phase.
Clay paste mixture
The support to be treated must be perfectly clean and smooth. As it does not contain glue an adhesive substance must be added to bole. It is thus advisable to dilute the product in a 1:1 ratio with a 90% water and 10% rabbit skin glue or fish glue solution. Once this mixture is blended it can be applied with a brush and the gold leaf applied when it is still wet. Once applied the product tends to dry in around two hours.
10 – 12 m² / kg.
Store in a cool, dry place in its own container, closed, and away from direct light and heat. The ideal temperature is 15-25°C with humidity under 50%.
Dilution percentage, application method and quantities applied may significantly affect workability time frames. The most suitable application methods should be determined experimentally on the basis of support used and desired result.