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

https://reidjgcr153.image-perth.org/copper-doesn-t-lie-the-instance-for-custom-made-chimney-shrouds-and-a-100-year-roofing-system-technique

I marvelled exactly how patination is both art and chemistry; managed oxidation, acids, and waxes develop living coatings that advance with weather condition yet stay protectively sealed.