In the Middle Ages, gold was used not only for decoration but also on extensive surfaces. On the clothes of the saints and on shrines, generously applied gold was considered to symbolise the celestial spheres.
The carved wooden sculpture was sized with glue, and then layers were applied. After drying, they were carefully smoothed and sealed with shellac, glue or egg-white, so as not to absorb the adhesive of future layers. A bole layer was then brushed on the sealed surface. Bole is a kind of clay which exists in various colours and the shade of it affected even the tone of the gold leaf. Gold leaf hammered into thin sheets was then applied to the bole layers. In the course of polishing, the gold leaf was polished using agate, animal tooth or bone. Meanwhile, matte surfaces were simply coated with liquid containing glue resulting in a more matte surface. At the same time there was another technique for matting polished gold when gold was glued to an oil-based adhesive liquid.
(Workshop of Robert Moreau: Three men, inv. no.:84.9.)