Wonders of enamel
Credits: Cloisonné © Vacheron Constantin
Intimately associated with jewellery and gold since Antiquity, enamel was the natural choice for the decoration of watches during the Renaissance.
Three thin layers of this enamel, when polished, give the uniquely pure and luminous white of a Fine Watch dial. Patterns can then be acid-engraved or manually engraved, and numerals and other markings transferred.
Superb coloured enamels are obtained by adding different metal oxides to transparent enamel. They are applied to the metal (usually gold) base with a quill or a very fine brush. The enamel is fired and the process repeated as many times as is necessary to obtain the desired colour.
A Fine Watch is enamelled using any of the three principal techniques.
The enamellist traces the contours of the pattern using fine gold wires, not even the width of a hair. The cells formed by these wires are then filled with layer after layer of enamel. The enamellist performs this operation up to sixty times, and fires the piece twelve or fifteen times, as each colour fuses at a different temperature.
The engraver incises the metal to form the details of the chosen motif. The enamellist then fills these hollows with enamel, one colour at a time, firing each one in the furnace.
Miniature painting on enamel:
This technique, which appeared circa 1620-1630, can be likened to oil painting. The miniaturist outlines his subject on a surface that has been enamelled on both sides. The colour is then gradually built up using finely-ground enamel mixed to consistency with essential oil and fired between each application. The softest colours are usually applied last of all, and fired a final time. Even at this ultimate stage, a blast of heat can still irremediably erase all or part of the work.
Only at the very end of this long process will the enamellist discover whether his work is a success, or not. The piece is red-hot when taken out of the furnace then blackens as it cools down until the miracle of the colours is finally revealed.