Gold leaf has been made for thousands of years. The process is long and comprises many steps. Though gold leaf used to be beaten by hand by a few specialized artisans, the process has been modernized by the development and use of precision robots so as to ensure that each gold leaf produced has the most even thickness possible.
First, the gold is mixed with precise quantities of copper, silver or palladium, depending on the required tone. Gold mixed with copper is called “red gold”, when mixed with silver it is called “white gold” and adding palladium makes the gold leaf more resistant.
The quantities need to be as precise as possible to ensure homogenous color from one batch to another, meaning that the metals need to be measured out to the third digit after the comma.
These “recipes” are a mark of quality. Once the ingredients are prepared, they are melted together in a crucible at 1200 C and cast into small flat rectangles measuring 20x4x1 cm. The process is the same for most alloys, except white gold, which is melted in an induction oven.
Metals, ready to be melted
An alloy being cast into a rectangular mold
These rectangles are rolled out into 70 meter long ribbons, checked for uniform thickness (approximately 70µ at this stage), then re-heated because the gold has become solid and rolled again until the ribbon reaches a length of 150m and a thickness of7µ.
Thin gold ribbon
Next the ribbon is cut into even-sized squares (4x4 cm). These are placed between square sheets of a special type of plastic which are bound into packages of 2000 leaves each and placed in a machine to be beaten a first time.
Gold-beating machine in action
As the gold expands through this process, it needs to be resized and transferred to several new sets of plastic leaves for further beating to achieve its final thickness.
A worker transfers gold-leaf into a new booklet for further beating
The machines are calibrated to several beating patterns, to make sure that the thickness of the gold-leaf is as even as possible. The final thickness of a gold-leaf is 1/7000 mm. The size of the gold leaf can be adapted to the needs of the client. The final preparation and assembly of the booklets of gold-leaf is the one stage that still needs to be done by hand. Trained employees cut and lift the gold-leaves one by one into the booklets. The scraps are collected and pressed so as to be re-used for another batch.
A worker cutting gold-leaf before transferring it to the booklet