The bolus to brown Lefranc comes in the form of a very fine ground clay paste. This formula ensures a superior product of the highest quality.
The Lefranc bolus does not contain glues, therefore it is necessary to add rabbit or fish glue before application.
The bolus is used in the gilding as a base for the gold leaf, guaranteeing a stable and perfectly homogeneous application to the gilder.
The color of the bolus influences the tone of the metallic leaf (both real and imitation) that we will apply above it.
In fact, with a red background you get warmer shades, while with a paler yellow background. The black bole is instead more suitable as a base for the silver leaf (both real and imitation).
The bolus is essential for gouache gilding, as its adhesive power allows the metal leaf to adhere and to carry out the subsequent burnishing with agate stone