Gold foil is a thin sheet made of hammered gold. According to the traditional gold foil making process, 99.99% pure gold bars are used as raw materials, and proportioned with an amount of silver, copper and others metal elements that are added to meet the requirement for gold content. After going through a dozen of special processing procedures, such as baking, hammering and cutting, the materials become gold-colored, bright, soft, ultra-light and ultra-thin. Thickness is about 0.11 microns.   Gold leaf standard size is 9.99 x 9.33 cm, but others commonly used specifications are also available, such as 10.9 cm x 10.9 cm, 8.5 cm x 8.5 cm, 8 cm x 8 cm, 5.5 cm x 5.5 cm, 4.3 cm x 4.3 cm, 2.75 cm x 2.75 cm.