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

https://www.tumblr.com/loftilynoisytwist/817210852238311424/salvo-metal-works-and-the-fact-of-copper

I was surprised how patination is both art and chemistry; managed oxidation, acids, and waxes produce living coatings that progress with weather condition yet remain protectively secured.