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

https://www.scribd.com/document/1058932948/Leader-Boxes-Constructed-for-Generations-Hand-Fabricated-Copper-That-Doesn-t-Compromise-215768

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