Gold-beating is a very ancient art, having been practised from a remote period among oriental nations. Gilding with leaf-gold is found on the coffins of Egyptian mummies, on some Greek pottery vases of as early a date as the 4th or 5th century B.C., and on portions of the palaces of ancient Rome. Beckmann states that the German monk Theophilus, who appears to have lived at least as early as the 12th century, describes the process nearly as it is at present, the gold having been beaten between parchment, which is practically the same as the modern method. Formerly the gold-beater's art was largely practised in Florence, but in that city the production of fine gold-leaf has greatly diminished during the latter half of the 19th century through French and German competition, the latter country especially now making large quantities of an inferior gold-leaf. Gold-beating is practised in most of the large towns of the United Kingdom, but London is its chief centre.
According to the shade of colour required gold is alloyed for beating either with silver or copper or with both. The proportion of copper rarely exceeds one-twentieth part that of the gold, but the quantity of silver in the alloy is sometimes much larger. The ingot being prepared, it is rolled out into a ribbon 1½ inches wide, a 10-feet length of which weighs an ounce. This length of ribbon is then annealed and cut into about 75 pieces of equal weight. Formerly these were placed between leaves of vellum, but a tough kind of paper is now used with a leaf of vellum at intervals through the packet, which is from 3½ to 4 inches square. The pile of bits of gold ribbon thus interleaved is called a 'cutch,' and this, having been placed upon a thick block of marble about 9 inches square, resting on a strong bench, is beaten with a hammer weighing from 15 to 17 lb., till the pieces of gold extend to the size of the squares of the paper. The hammer rebounds by the elasticity of the vellum, which saves or at least lessens the labour of lifting it. Each square of gold in the cutch is now taken out, cut into four pieces, and placed between leaves of Gold-beater's Skin (q.v.). This packet, termed a 'shoder,' is beaten with a 9-lb. hammer for about two hours, or six times as long as in the first or cutch beating. For the final beating the gold leaves from the shoder are again divided into four, and each piece placed between leaves of fine gold-beater's skin, about 950 of which form a packet termed a 'mould.' After four hours' beating with a 7-lb. hammer the gold-leaf in the mould is of the thickness usually sold, which averages the 282,000th part of an inch. Each skin of the mould is rubbed over with calcined gypsum to prevent the gold adhering to it. One grain of gold in the form of gold-leaf of the ordinary thickness used in gilding measures about 56 square inches, but it can be beaten out to the extent of 75 square inches. A grain of silver can be beaten out to a still greater extent, but the leaf would really be thicker, since this metal has not nearly the density of gold.
An alloy consisting of 37 grains of gold, 2 of silver, and 1 of copper makes a leaf with a deep yellow colour. A compound containing 4 grains of gold to 1 of silver gives a pale-yellow leaf, but as the proportion of silver is lessened it becomes deeper in the yellow. Seen by transmitted light gold-leaf when only slightly alloyed appears green, but if it contains a large proportion of silver its colour is violet. For external gilding, leaf made from pure gold is the best, as it does not tarnish by atmospheric influences; but it is not so convenient for ordinary purposes.