Enamelling is fusing glass to metal under high heat. The type of glass fused to metal with heat is porcelain enamel and not resin, which is cold or unfired enamel. People use several techniques when fusing enamel to metal. Some techniques involve the preparation of metal while others focus on applying the enamel. Artists and crafters apply enamel to such metal objects as vases, spoons and jewellery.
Basse taille or low-cut is a technique that involves creating a pattern in a metal backing prior to enamelling. Making depressions in metal through an etching process that leaves metal exposed after enamelling is champlevé or raised-field. In Japan, a technique called ginbari foil uses an embossing plate and embossing foil to create lines. The mechanical cutting of lines on metal is guilloche or engine turning.
Grisaille is applying enamel in a monochrome, using a build-up of white overlays on a black background. Applying acid-resistant enamel to a bare metal surface in multiple layers to build up a relief design, that is sculptural in effect, is impasto. Applying different colours of enamel next to each other without separation by wire or surface metal is Limoges. The plique-a-jour technique resembles stained glass that may be surface tension enamelled or etched-enamelled.
Enamelled pieces are often enhanced with decorative additives such as China paints. China paints are low-fire ceramic materials used on the outer surface of enamels. Overglazes and underglazes are finely ground pigments applied on top of or underneath enamelling layers. Underglazes are effective in the basse taille metal technique. Some artists inset gemstones or fine metal grains by fusing them to the metal and enamelling around them.
Heating and Other Techniques
In most instances, heating requires the use of a kiln to harden the enamel coating on objects. Some techniques involve the use of a fire torch. Firescale enamelling is the use of oxide build-up on metal to form lines. Separation enamel is a special type of enamel that indents regular enamel and changes its colour to produce a one-of-a-kind piece of art.
Enamels can be opaque, transparent or translucent. Colours come from metallic salts mixed in with the powdered glass, such as iron oxide for green enamel and cobalt for blue. Artists can mix and match colours along with application and heating techniques to form various effects.