Shell gold technique or “nicchia” (niche) gilding is achieved by mixing gold dust with a binder (paint, animal glue or arabic gum) and then spreading the mixture with a brush. The technique is essentially used for the definition of small details or for the gilding of finely carved parts, in order to avoid a burdening of the work with the preparations necessary for the other gilding techniques.
Giorgio Vasari testifies in the introduction of the Vite (1568): “One grounds these (gold) sheets in a glass cup with a little honey and gum, which is used by the miniaturists, and by many others that delight themselves in making outlines and very subtle lights in the paintings using the brush ”.
French: Dorure en coquille – Italian: Doratura a conchiglia – Spanish: Dorado en polvo – German: Muschelvergoldung
Shell gold or gold for painters.
Particularly fine gold powder usually mixed with arabic gum. The various shades tending to red or green are obtained by adding small quantities of either copper or silver. The term shell alludes to the container – a shell, in fact – once used by painters for its use in gilding.
French: Or en coquille – Italian: Oro in polvere– Spanish: Oro en polvo – German: Muschelgold