Goldleaf
Collier's New Encyclopedia (1921)
fine gold beaten into thin leaves. A small percentage of silver and copper is added to the gold for beating, about 1½ per cent. of alloy. The ingot is rolled into a ribbon by repeated passage between rollers, and this ribbon has a thickness of 1-800 of an inch, a surface of 500 square inches to an ounce of gold. It is then cut into pieces of about 1 inch square, placed between pieces of goldbeater's skin 4 inches square, and beaten with a ponderous hammer on a smooth marble slab till the gold has thinned and expanded to the size of the vellum. Each piece of gold is then again divided into 4, placed between pieces of goldbeater's skin as before, and again beaten till it expands to the size of the skin. A third and a fourth beating follow. An ounce of gold in the form of a cube, cube, 54 lines in length, breadth, and thickness, can be so extended by the goldbeaters as to cover a surface of more than 1,466½ square feet. Wood, plaster, papier-maché, and many other substances may be gilded by covering them with goldleaf stuck on with a kind of sizing or glue. The gold leaf is not put on the wood, plaster, etc., itself, but on a mixture of whiting and glue called size. In gilding picture frames, for example, the wood is painted with four or five coats of size put on hot. This is carefully smoothed, when dry, with pumice stone and fine sandpaper, and another size, made of clay, red chalk, black lead, suet, etc., is then put on. This, which is called gold size, is the groundwork for the gold leaf. In gilding on metals or surfaces to be much in the open air an oil size is used.
What Has Changed in the Last Century
The process Collier's described in 1921 is still recognisable: gold alloyed with a little silver and copper, rolled to a ribbon, then beaten in packets until an ounce covers a room's worth of surface. What has gone is much of the hand labour and the goldbeater's skin made from ox gut; mechanical hammers and synthetic interleaving papers now do most of the work, and the great bulk of surviving hand production is concentrated in a few centres such as Kanazawa in Japan and Schwabach in Germany. Industry, meanwhile, has abandoned leaf altogether for most purposes: gold films for electronics, optics and spacecraft shielding are laid down by electroplating or vacuum deposition, in layers far thinner than any beater could achieve. The gilder's sizes, gesso grounds and oil size for outdoor work are still taught and used much as the entry sets them out, alongside cheaper imitation leaf of aluminium or brass, and edible gold leaf on food.
Written for this edition, 2026.