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

https://www.tumblr.com/loftilynoisytwist/817146362467680256/crowning-the-roofline-copper-finials-that-verify

I marvelled exactly how patination is both art and chemistry; managed oxidation, acids, and waxes develop living finishes that develop with weather yet continue to be protectively sealed.