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

https://storage.googleapis.com/metal-craftsmanship/serving-home-owners/uncategorized/leader-boxes-constructed-to-last-the-engineers-copper-standard.html

I was surprised just how patination is both art and chemistry; managed oxidation, acids, and waxes develop living surfaces that develop with weather yet continue to be protectively sealed.