Goldbeating

Goldbeating is the process of hammering gold into an extremely thin unbroken sheet for use in gilding.

History

5,000 years ago, Egyptian artisans recognized the extraordinary durability and malleability of gold and became the first goldbeaters and gilders. They pounded gold using a round stone to create the thinnest leaf possible. Except for the introduction of a cast iron hammer and a few other innovations, the tools and techniques have remained virtually unchanged for thousands of years.

Process

Rolling

24karat gold is used to make gold leaf. The karat and color of leaf varies depending the amount of silver or copper added. Most goldbeaters make 23karat 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 eight inches long, one and a quarter inches wide, and three-eighths of an inch thick. The bar of gold is put through a rolling mill repeatedly, the rollers are adjusted each time to make the gold thinner and thinner. The eight-inch bar of gold is rolled to 1/1000 of an inch thick and is now about fifty-six feet long.

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 membrane (Goldbeater's skin) was used to interleave the gold as it was beaten, but today other materials such as Mylar 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's wrapped in several bands of parchment that 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 or granite. These stone blocks were sometimes placed on top of a tree trunk set deep into the ground. This created greater resiliency for the hammer. The beating of the cutch will take 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. Rotating and turning over the packet ensures 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 cutch which is four inches square. 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 made from malacca cane. The mold contains 1,500 pieces of gold. Before the mold is filled with gold, the skins are coated with a gypsum powder. This process is called briming, and it prevents the delicate gold leaf from sticking to the skins. The mold is beaten with an eight-pound hammer for three to four hours until it has been beaten into a circle about six inches in diameter. The gold is so thin now that the beater is able to check the quality of the product by holding it up to the light and looking through it. The finished leaf forms an unbroken sheet of gold with a thickness of 1/250,000 of an inch. The leaf is taken out of the mold, cut into a three and three-eight inch square and packaged in tissue-paper books containing twenty-five leaves.

ee also

*Metal leaf
*Gilding