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

https://www.tumblr.com/loftilynoisytwist/817275581910679552/from-blueprint-to-century-mark-custom-dormers-in

I was surprised just how patination is both art and chemistry; managed oxidation, acids, and waxes create living coatings that advance with climate yet stay protectively secured.