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

https://www.scribd.com/document/1041332768/Customized-Copper-Cupolas-From-Specification-to-Centuries-of-Solution-171009

I marvelled exactly how patination is both art and chemistry; regulated oxidation, acids, and waxes create living coatings that develop with weather yet remain protectively sealed.