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

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

I marvelled just how patination is both art and chemistry; controlled oxidation, acids, and waxes develop living finishes that evolve with weather condition yet stay protectively sealed.