I marvelled exactly how patination is both art and chemistry; managed oxidation, acids

https://storage.googleapis.com/metal-craftsmanship/serving-home-owners/uncategorized/dormers-you-can-trust-the-honest-aging-of-hand-fabricated-copper.html

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