Gold has always had an almost mystical allure, capturing the imagination and bestowing a sense of grandeur and richness on the furniture and interiors it adorns. Over the centuries its popularity and demand have never noticeably waned. Like many others, Gosling maintains an enduring fascination with this precious metal, and their work with gilders has ensured that the art of gilding has survived and developed.
Gilding is the art of applying a thin layer of metal to an object or surface. While any metal can be applied using the technique, including silver, palladium, aluminium and copper alloys, gold is by far the preferred material due to its lustre and non-tarnishing properties.
The Egyptians used gold leaf and gold wire three thousand years ago, and they experimented with different alloys of gold and other metals to achieve varying shades in their gilding. A striking example of Egyptian gilded furniture is the throne of Tutankhamun discovered in the antechamber of his tomb.
The last remaining supplies of beaten English gold leaf, with a gilder’s tip; a traditional gilder’s cushion with side sections in vellum (old vellum documents are traditionally used for this); applying the gold leaf in the oil-gilding technique with a gilder’s tip; Peter Binnington applying the gold leaf.
The age of Roman luxury, generally agreed to have begun after the sacking of Carthage in 146 BCE, was heralded by the gilding of the interior timber ceilings of temples and palaces including the Capitol. The gold used in ancient Rome was applied so thickly that the traces remaining today retain their brilliance and solidity.
By the first century BCE mercury gilding of bronze and copper had also been mastered, as Vitruvius mentions. Early examples of gilding show that the gold was applied to a gesso base prepared by mixing chalk or marble dust with animal glue.
Over the centuries gilding has been used commonly as the most sumptuous of decorative arts on picture- or mirror-frames and furniture, in both religious and secular arts as well as throughout architecture. Experimentation and research has led to differing shades, textures and lustres of gilding being developed and perfected; and these artistic and scientific techniques have led to its application to a wide variety of surfaces.
Gold is an extremely soft and malleable material which means it can be worked into wire or sheets of only a few hundred atoms in diameter. It can be hammered by hand, while cold, into thin sheets — one hundred thousand leaves will be only 1.5 cm thick. One troy ounce of 31.1 g (not even the weight of most chocolate bars) can be beaten into gold leaf to cover 9m².
The basic techniques of gilding have changed little since the earliest times. Although certain basic procedures apply to all types of gilding — for example very careful preparation of the ground to be gilded — there is a very wide range of methods and materials used, depending on the nature of the support and the type of object being gilded.
Flattening down the gold leaf.
The two main types of gilding used in architectural or furniture decoration are oil or mordant gilding and water gilding, along with fire or mercury gilding and electroplating for smaller, decorative elements which are then fixed to the furniture.
Water gilding gives an extremely refined and elegant finish and is used mainly for fine objects such as frames, furniture, sculpture, fine art and religious artifacts; but also for the decoration of stately buildings. Firstly a gesso, a base made of chalk or gypsum mixed with a size (an animal glue, usually from rabbit skin), is applied to the surface to be gilded. This is followed by a thin size wash, often coloured with ochre, and then by the clay-like substance, bole. Glair (adhesive made from egg-white) may also be used as an alternative method of glazing. This is much more fragile and tends to ‘craze’, or develop a fine network of cracks, over time. Different shades of bole give varying lustres as the gold leaf is so thin that the colour of the bole will affect the appearance, particularly in the case of burnished gilt work. Water and a tiny amount of size, mixed with alcohol (usually gin) to break down the surface tension, is applied to the dried bole in small areas at a time. This sticks the loose gold leaf used in water gilding to the surface.
Each leaf has to be picked up with a gilder’s tip and applied with great care; a wetting brush or mop is used to wet the bole with the size water and, through capillary action, the loose gold leaf is pulled onto the surface. This type of gilding is probably the most rewarding and most time-consuming technique used today by individual craftsman. however it is also one of the most fragile types of gilding; the use of clay, chalk and gypsum, which are hydroscopic and water-soluble, mixed with an animal protein, make it vulnerable to water and moisture damage.
Thomas hope (1769:1831), pier table, London, c.1800. probably gilded pine, with black marble, mirror glass and bronze mounts. The design of this table, with pairs of caryatids on plinths supporting a shelf, is typical of french console tables of 1805-10.
Burnishing is a technique used to achieve a high lustre by rubbing the applied gold leaf with a tool tipped by a polished agate stone. These tools, or burnishers, come in many different sizes and angles for specialized work. Water gilding is universally considered the most superior of all methods as it allows for more variety and a far higher lustre in the finish. Eighteenth-century French gilders were able to burnish a frame to varying degrees in different places, depending on the lighting in the room it was intended for, so it caught and reflected the light evenly, thus balancing the reflectiveness.
Oil gilding is the simplest form and is mainly used for decorative architectural details, fixed furnishings and exterior work. However there are plenty of cases where it is used for furniture, and in particular picture frames and mirrors, but as oil gilding cannot be burnished it can never achieve the shine or depth of water gilding.
To carry out oil gilding the surface has to be both dry and non-porous and, depending on what result is desired, the oil size may be applied over a coloured base. This oil size (usually linseed oil) will have a known drying time — a time window in which it stays tacky so the gold, as either leaf or transfer gold (fixed onto paper), can be applied to the surface. As with water gilding, the colour beneath the oil size will show through the gold leaf and a combination of oil and water gilding on one object is quite common to give the object more definition.
Fire gilding or mercury gilding can only be applied on specific, well-prepared metals or alloys and is a highly toxic process. The most common examples of this method in furniture are the gilt-bronze mounts which are used as decorative items on furniture particularly in the eighteenth and nineteenth centuries.
Electroplating involves gold, dissolved in an aqueous solution, being deposited onto another conductive object using an electric current. The thickness of gold deposited onto the surface can be controlled with the electric current and with the exposure time. This process, invented in the early nineteenth century, became an industrialised process within several decades and is today used on many everyday items.
Throne made of wood overlaid with gold leaf from the tomb of Tutankhamun, Valley of the Kings, Dynasty XVIII, c. 1352 BCE .