Plique-à-jour

The technique is similar to that of cloisonné, but using a temporary backing that after firing is dissolved by acid or rubbed away.

The outstanding early examples that survive are "the decorative insets in the early fifteenth-century Mérode Cup (Burgundian cup) at the Victoria and Albert Museum in London, a Swiss early sixteenth-century plique-à-jour enamel plaque representing the family of the Virgin Mary in the Metropolitan Museum of Art in New York,[8] and the eight pinnacle points over the front of the eleventh-century Saint Stephen's Crown in Hungary".

The technique was revived in the late 19th century movement of revivalist jewellery, and became especially popular in Russia and Scandinavia.

Norwegian jewellers included David Andersen and J. Tostrup in Oslo,[10] and Martin Hummer in Bergen.

This leaves empty spaces or "cells" to fill with enamel powders (ground glass).

Shotai shippo ("Japanese plique-à-jour"): A layer of flux (clear enamel) is fired over a copper form.

Wires are fired onto the flux (similar to cloisonné) and the resulting areas are enameled in the colors of choice.

When all the enameling is finished, the copper base is etched away leaving a translucent shell of plique-à-jour.