The process of leaf gilding means the covering with gold by the application of gold leaf (or foil). The term leaf is reserved for gold less than 1 micron thick. Sometimes held mechanically by roughening the surface or by a diffusion bond to the substrate metal. Commonly, however, the term applies to application of a metal in leaf form to another metal by adhesion, using an oil size (a thin coating of an oil which dries quickly - 3 - 12 hours). When almost dry, the gold leaf is applied, this sticks to the tacky oil surface. The best gold leaf is normally 231/4 carat and comes in leaves 31/4 square and in books of 25 leaves. Gold leaf comes in many colours and qualities. Other metal leaf can also be applied by oil gilding, for example:
Gold leaf - rouge, regence, jaune, citron.
Silver leaf - caplan, gris, blans, (will tarnish if not lacquered).
Palladium - bright white metal, will not tarnish.
Platinum - white/grey metal, will not tarnish.
Aluminium - Schlagaliminium leaf.
Copper - will tarnish
Dutch metal - will tarnish.
Transfer leaf is gold or silver leaf lightly adhered to tissue paper for ease of application.
Water gilding is not used on metalwork - found on gilded furniture and picture frames.