Bronzes have the same qualities as the baser leaf metals, and the same precautions must be observed in using them. They must not be mixed with oil varnishes, or oil mediums, but can be put upon japanners' gold size, or upon any spirit varnishes in powder form. They can be mixed and applied as liquids in any spirit varnish, or in size or gum, though the tendency of gum to become acid sometimes turns the bronze black. In bronzing with the powder, the size, usually japanners' gold size, is applied, and when tacky, the bronze is dusted on with a rabbit's foot, a wad of close cloth, or a chamois leather pad. The bronze is protected by a thin coat of lacquer, and then varnished in the ordinary way.

Bronzing should never be varnished over with oil copal varnishes, as it will rapidly lose color and oxidize if so varnished, some of the commoner house-painters' oak varnishes have so little oil in them that this effect does not follow rapidly. If metals, silver, or gold be sized with a clear jelly of gelatine size, or thinly lacquered, they may be varnished with any kind of varnish, as the interleaf of size will stop the direct action of the varnish upon the metal.

Bronzing is sometimes used over paint to give the effect of metal. Thus a piece of iron casting may be painted green or copper color, and then the highest portions of the relief touched with bronze. This is done by coating the article with japanners' varnish or gold size, and when tacky dusting over a little powder bronze, which can be applied by a piece of cloth or velvet rubbed in the powder. The bronze should not be applied to the bare oil paint. The color of the bronze must bear a correct relation to the color of the paint used.