Side quality is whatever: deburring, cleaning
https://archeraiqf972.cavandoragh.org/100-years-of-patina-the-architect-s-case-for-hand-fabricated-copper-cupolas-by-salvo-metal-works
Side quality is every little thing: deburring, cleaning, and micro-grain sanding prepare surfaces so finishes bond uniformly and exposed seams check out as refined, continual planes.