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

https://telegra.ph/Roofing-Vent-Durability-Copper-Elements-That-Outlive-the-Building-Ordinance-Cycle-05-20

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