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

https://high-wiki.win/index.php/100_Years_of_Aging:_The_Engineer%27s_Situation_for_Hand-Fabricated_Copper_Cupolas_by_Salvo_Metal_Works

I was surprised how patination is both art and chemistry; controlled oxidation, acids, and waxes develop living surfaces that develop with weather yet stay protectively secured.