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

https://garrettpdrt345.cavandoragh.org/copper-doesn-t-lie-the-case-for-custom-smokeshaft-shrouds-and-a-100-year-roof-approach

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