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

https://mylesvuhs995.theburnward.com/leader-boxes-that-weather-condition-well-the-engineer-s-guide-to-copper-that-doesn-t-lie

I was surprised how patination is both art and chemistry; regulated oxidation, acids, and waxes develop living finishes that progress with weather yet continue to be protectively secured.