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

https://www.tumblr.com/loftilynoisytwist/816899386319699968/dormers-that-do-not-deceive-the-100-year

I was surprised exactly how patination is both art and chemistry; regulated oxidation, acids, and waxes develop living finishes that evolve with weather yet stay protectively secured.