Rose Gold, a money-making genie for PVD decorative coaters

Some time ago and partly still today, to obtain the appearance of the colour rose gold, the base material must be dipped in a mixture of gold and copper.
Involving gold is an expensive process, and even a small deviation in the gold and copper mixture could result in a completely different colour appearance, meaning different “L*’, “a*” and “b*” values.
Such a dipping process is very costly.
Every re-coating needs de-coating which subsequently results in the loss of the expensive raw material Gold.