[PeterisP]

What technology? The main technology needed to work gold leaf is a smelter to pour the initial shape, and after that you don't need any weird materials or machines, it is just skilled and careful hammering. Going thinner doesn't require a different technology, it requires a more skilled goldbeater, even noways sub-µm gold leaf is routinely done with traditional methods.

[kadoban]

They wouldn't have had electroplating, but yeah you don't need that if you're okay with just spending a lot of time and care on it instead.