I was surprised how patination is both art and chemistry; regulated oxidation, acids

https://wiki-dale.win/index.php/Copper_Doesn%27t_Lie:_Why_Architects_Pick_Salvo_Metal_Works_for_Customized_Chimney_Shrouds_that_Last_a_Century

I marvelled exactly how patination is both art and chemistry; controlled oxidation, acids, and waxes develop living finishes that progress with climate yet stay protectively secured.