Reading enamel decoration
Glass fused to metal.
Champlevé enamel sits in cells cut or cast into the metal; cloisonné sits between soldered wire walls. Which technique is used helps date and place an object — medieval Limoges work, for instance, is champlevé on copper, gilded around deep blues.
Old enamel often has fine crazing and small losses; colours can be muted by burial. Over-bright, flawless enamel on a worn object is a warning sign, and so is enamel standing proud of cells that wear should have levelled.
Note whether wear on the metal matches wear on the enamel — a mismatch can mean later restoration. Under magnification, replacement fills often show as resin: glossier, softer, and bubble-free.
Lost enamel is part of the story, not a flaw to hide. Record which cells survive, their colours, and any restoration you can see or suspect.