How Traditional Gilding Techniques Survive in a World of Gold Paint

Gold paint, the aerosol-sprayed substitute adorning picture frames in every homeware shop, is not gold. It is typically bronze or aluminium powder in lacquer that tarnishes within months. Genuine gold leaf gilding maintains its brilliance for centuries, which is why the Dome of the Rock in Jerusalem still gleams after thirteen hundred years.

Gilding divides into two methods, and the distinction governs where each can be used. Water gilding burnishes to a mirror but its binder dissolves in rain, so it stays indoors on frames, furniture and interior mouldings. Anything outside, including the statue of Prince Albert regilded during the Albert Memorial's restoration in the 1990s, is oil gilded, laid onto a slow-drying oil size. Oil gilding cannot be burnished and reads as a softer matte gold, but it survives weather for decades.

Traditional water gilding begins with preparing the surface with multiple coats of gesso, chalk and rabbit-skin glue, sanded to glass-like smoothness. Over the gesso, bole, a fine clay tinted with iron oxide, is applied in coats and burnished. This layer provides colour and cushion giving gilding its characteristic depth.

The gold leaf, beaten to one-tenth of a micrometre, is laid onto the bole after moistening with water or gelatine. The moisture reactivates bole's glue creating adhesion. The gilder lifts fragile leaf on a squirrel hair tip and positions it with a single decisive motion. Once the leaf touches wet surface, it bonds instantly.

Burnishing transforms applied gold from matte to mirror lustre. Using an agate burnisher, the gilder rubs with firm pressure. The agate compresses the leaf against the bole, smoothing irregularities and increasing reflectance. The transformation from dull to brilliant is dramatic with each stroke.

Leaf comes in grades and formats. A book holds 25 leaves at eighty millimetres square, about a sixth of a square metre in total; 23.75 carat is the standard for exterior work, while lemon, white and moon golds are alloys with visibly different tones. Loose leaf is what water gilding requires, transfer leaf pressed onto tissue what you want outdoors in a breeze. Manetti in Florence has beaten gold since 1820 and Cornelissen in Bloomsbury has supplied the London trade since 1855.

The economics of genuine gilding are less prohibitive than assumed. A book of gold leaf costs roughly fifty pounds and covers modest areas. A picture frame requires two to three books, making gold itself a small fraction of total cost, dominated by skilled labour of preparation and application.

Which leads to the one rule for owners. The binder under water gilding is rabbit-skin glue, and glue is water-soluble, so a damp cloth takes the gold off along with the dirt, as will most household cleaners. Dust with a soft brush and nothing else. If a frame has gone brown-green in the recesses beneath a yellowing lacquer, it is not gold at all but schlag, the copper-zinc imitation leaf, which tarnishes and has to be sealed.

If you own a gilded antique, resist the temptation to repaint with gold paint. Consult a professional gilder who can assess the original surface and repair using compatible traditional techniques. Preservation maintains both beauty and value. Find a gilder at https://www.societyofgilders.org