Goldbeating is the process of hammering

gold Gold is a chemical element with the Symbol (chemistry), symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a Brightness, bright, slightly orange-yellow, dense, s ...

into an extremely thin unbroken sheet for use in

gilding Gilding is a decorative technique for applying a very thin coating of gold over solid surfaces such as metal (most common), wood, porcelain, or stone. A gilded object is also described as "gilt". Where metal is gilded, the metal below was tradi ...

History

5,000 years ago, Egyptian artisans recognized the extraordinary durability and

malleability Ductility is a mechanical property commonly described as a material's amenability to drawing (e.g. into wire). In materials science, ductility is defined by the degree to which a material can sustain plastic deformation under tensile stre ...

of gold and became the first goldbeaters and gilders. They pounded gold using a round stone to create the thinnest

leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ...

possible. Except for the introduction of a

cast iron Cast iron is a class of iron–carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impuriti ...

hammer A hammer is a tool, most often a hand tool, consisting of a weighted "head" fixed to a long handle that is swung to deliver an impact to a small area of an object. This can be, for example, to drive nails into wood, to shape metal (as ...

and a few other innovations, the tools and techniques have remained virtually unchanged for thousands of years.

Process

Rolling

The karat and color of gold leaf varies depending on the amount of silver or copper added to the gold. Most goldbeaters make 22 karat leaf. The gold and its alloy are put in a crucible and melted in a furnace. The liquid gold is poured into a mold to cast it into a bar. The bar of gold is put through a rolling mill repeatedly. Each time through the mill, the rollers are adjusted closer and closer to each other, to make the gold thinner and thinner. The bar is rolled to a thickness of .

Beating

After rolling, the ribbon of gold is cut into one-inch squares. The first step in the beating process is called the ''cutch''. The cutch is made up of approximately 150 skins. In the early days of the trade, ox

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans a ...

membrane (

Goldbeater's skin Goldbeater's skin is the processed outer membrane of the intestine of an animal, typically cattle, which is valued for its strength against tearing. The term derives from its traditional use as durable layers interleaved between sheets of gold st ...

) was used to interleave the gold as it was beaten. Today other materials, such as

Mylar BoPET (biaxially-oriented polyethylene terephthalate) is a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength, chemical and dimensional stability, transparency, reflectivity, gas and ar ...

, are used. Using wooden pincers, the preparer picks up each square of gold and places it in the center of each skin. When the cutch is filled with the small gold squares, it is wrapped in several bands of

parchment Parchment is a writing material made from specially prepared untanned skins of animals—primarily sheep, calves, and goats. It has been used as a writing medium for over two millennia. Vellum is a finer quality parchment made from the skins of ...

which serve to hold the packet together during the beating. Parchment is still the best material known to withstand the hours of repeated hammer blows needed to beat the gold. The gold is beaten on a large, heavy block of

marble Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is typically not foliated (layered), although there are exceptions. In geology, the term ''marble'' refers to metamorphose ...

granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies unde ...

. These stone blocks were sometimes placed on top of a tree trunk set deep into the ground. This created greater resiliency for the hammer. Beating of the cutch by hand takes about one hour using a fifteen-pound hammer. The goldbeater instinctively follows a pattern and sets up a rhythm, striking the packet with up to seventy strokes a minute . The packet is rotated and turned over to ensure that the gold inside expands evenly in all directions. The original small squares of gold are beaten until they have expanded to the outer edges of the four inch square cutch. The gold is taken out of the cutch and each piece is cut into four pieces with a knife. Using the pincers, these squares of gold are put into a second packet called the ''shoder'', which has approximately 1,500 skins. The shoder is beaten for about three hours until the gold has expanded to a five-inch square.

Packaging

The gold is taken out of the shoder and placed on a leather-covered surface. The gold is thin enough now that the cutter can simply blow on it to flatten it out. Using a wooden implement called a ''wagon'', the gold is quickly cut into four pieces and immediately placed in a packet called a mold for the final beating. The wagon has sharp cutting blades, traditionally made from malacca cane (

rattan Rattan, also spelled ratan, is the name for roughly 600 species of Old World climbing palms belonging to subfamily Calamoideae. The greatest diversity of rattan palm species and genera are in the closed- canopy old-growth tropical forests ...

). The mold contains 1,500 pieces of gold. Before the mold is filled with gold, the skins are coated with a

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and dry ...

powder. This process prevents the delicate gold leaf from sticking to the skins. The mold is beaten with an hammer for three to four hours until it has been beaten into a circle about in diameter. The finished leaf forms an unbroken sheet of gold with a thickness of approximately . After the leaves are taken out of the mold, they are conventionally cut into a square and packaged in tissue-paper books containing twenty-five leaves.

References

External links

Gold Beating
sections from 1903 American Library Edition Of Workshop Receipts Vol5 by Ernest Spon

(in German) partly illustrated history of goldbeating
Gold Beating 1959
an
Gold Beating Out Takes 1950-1959
two

British Pathé British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories, and Crown Dependencies. ** Britishness, the British identity and common culture * British English, ...

newsreel clips depicting the goldbeating process * {{Cite EB1911, wstitle=Goldbeating, short=x Gold Metal forming de:Goldschläger fr:Batteur d'or it:Battiloro ja:金箔#製造工程