The patina that is not polished
The dark film in the recesses is left on purpose — without it the relief disappears.
Silver tarnishes unevenly: on raised areas the film wears off with handling, in the recesses it stays. That contrast is what makes chasing legible.
Full polishing gives an even shine in which the pattern vanishes. Koval cleans only flat surfaces and never touches the relief — and shows two identical pieces side by side, one of which was fully polished at some point.
