I was surprised exactly how patination is both art and chemistry; regulated oxidation, acids

https://www.scribd.com/document/1042304429/Breathing-Easy-for-a-Century-Personalized-Copper-Roof-Vents-that-Keep-Executing-176128

I was surprised just how patination is both art and chemistry; controlled oxidation, acids, and waxes develop living surfaces that advance with weather condition yet continue to be protectively secured.