The History Of Gold Leaf
By ERLA ZWINGLE
Egyptians in Alexandria, Egypt were the first goldbeaters and gilders, pounding gold with a round stone, copper, or wooden hammers.
Greek sculptors used gold leaf in creating the “chrysoelephantine” statues of gods such as Athena at the Parthenon, or Zeus at the Temple of Olympia. The bare parts of the figure, such as arms, face, and legs were of ivory (elephantinos) and the armor, robes, hair and weapons were of gold (chrysos).
Eastern civilizations such as the Japanese have been using gold leaf for centuries as a decorative food and beverage garnish, and even in various medicines and remedies.
About 400 A.D. gold leaf began to be applied to the letters, borders, and figures in illuminated manuscripts in Constantinople, Ireland, and Italy. Gold leaf appeared on paintings as the sky (the color of heaven) and as the haloes surrounding the heads of holy figures. In Greek paintings, haloes were also sometimes shown on commanders and heroes. Austrian painter Gustav Klimt (1862 – 1918) is known for his use of gold leaf, famously exemplified in paintings such as “The Kiss.”
How thin is thin?
Gold leaf as thin as one micron was produced even in ancient times, and thicker foils or sheets were applied mechanically or with an adhesive. Late 14th-century Italian goldbeaters could obtain 145 leaves, similar in size to modern leaf, from a Venetian ducat (about 3.5 grams). The thickness of such a leaf can be estimated to have been about 0.2 microns (0.0002 mm).
Modern leaf can be even thinner – about. 0.1 microns, if machine made, and about 0.05 microns if hand beaten. At this thickness it is translucent, transmitting greenish light. At 0.134 microns, the leaf is thinner than the wavelength of light, ideal for covering the polycarbonate plastic visors of astronauts’ helmets to block both infrared and ultraviolet rays. The astronauts can see through it, but even this thin layer reduces the glare and heat of solar rays.
Gold-leaf comes in various thicknesses, qualities and colors. The leaf’s thickness is usually given not in microns, but by its weight per 1000 leaves. The thinnest leaves weigh around 12g per 1000, while the heaviest weigh around 50g per 1000, depending on the purity of the gold or its alloy. Gold powder and gold flakes are both made from gold leaf.
Soft but strong
Gold’s resistance to weather and pollution is one reason why it can be used on domes around the world from the Dome of the Rock in Jerusalem to the West Virginia State Capitol. “If you paint a dome you’re lucky if it lasts more than four or five years,” says Mathew Swift, president of M. Swift & Sons, whose family firm has been producing gold leaf for nearly 150 years, “but gold leaf will stay on for 25 or 30 years.” Then again, pure gold leaf—as we will soon learn—can last far, far longer.