Vintage view: Glittering enamel work known as guilloché

A form of what is termed, allochromatic glass, enamel is used to apply coloured, high shine detail to a metal object, and even in the hands of a master it is notoriously difficult work.

It’s a mixture of iron oxide, potassium oxide (potash), quartz sand, and borax coloured with metal oxides, crushed and then heated together.

Applied to a precious metal such as silver or gold, the enamel mix is heated to let it flow and level, and then cooled. During the cooling it shrinks and is in great danger of cracking if not well handled.

In really fine work, layers of enamel are reapplied and re-fired. For painting in enamel, up to 20 firings can be needed to accommodate the times for the different colouring oxides used.

Cloisonné enamelling is carried out by mapping out a design with tiny wires of metal in fields, and then infilling with the enamel. Known since ancient times the earliest examples were discovered in Cyprus and are said to date from as early as the 13th century BC (1300–1201 BC).

Plique à jour, a clever variant of Cloisonné allows the enamel to be hung in frames like tiny stain glass windows. Guilloché (said as gee-oh-shay) is a process of machine engraving on metal, set beneath enamelling to produce what we know as guilloché enamel.

Familiar for decorating gold and silver with tight pin stripes and spiralled ornament — engine turning with the help of a powered machine required enormous eye and hand skills using a rose engine lathe.

If you look at many bank notes, you can see intricate engine turned patternation of geometric swirls, squares and perfectly symmetrical wavy lines from the plates used to print the currency.

Remember the child’s Spirograph device and the pictures it produced? You get the idea.

Guilloché differs from the more familiar cloisonné enamel as glass mixtures lie over the engraved metal and is fused directly to it by heat.

Adding a texture to the surface of the silver on which glass was floated and fused, added a fascinating three dimensionality and refracted shine to enamel work with a variety of opacity and opalescence. Wavy lines were superb light catchers.

Basse taille, another form of engraving finished with enamel and first seen in Italy in the 14th century, was performed by working the metal by hand rather than machine, and the decoration is more fluid.

In the 1880s Carl Fabergé (1846-1920) produced the first true and fabulous guilloché work in his machined and enamelled surfaces for photo-frames, jewels, cigarette cases, desk clocks and most famously, his Easter eggs — used as personal gifts amongst the Russian Imperial family.

The workshop fired their enamels to far greater temperatures than standard, delivering silken smooth pieces polished up in over 150 known colours. His team could perfectly recreate the woven pattern of shot silk, with deeper cuts pooling the enamel to deliver a richer colour where required.

Guilloché enamel was a popular ingredient in jewellery and revived by top flight firms for presenting accessories for the monied classes from the late 19th century right up into the mid 20th century.

Expensive and time consuming to produce on tiny pieces — it spoke, as it had in the 18th century, of wealth and money-no-object indulgence.

A more recent example of affordable vintage basse taille enamel is the work of Norwegian silversmith David Anderson, in his wildly popular silver butterfly and leaf brooches and earrings from the1950s.

You can pick up nice examples in enamel with a touch of basse taille engraving beneath the surface, from around €30-€50 on Ebay. Domestic pieces with classic complex guilloché work by Andersen, such as a table salt cellar from the ’30s start around €250.

Something rare and exquisite — such as one of his baluster shaped enamel and silver cocktail shakers with four silver vessels belted in ebony — will set you back €5,000-€6,000. Victorian and Edwardian jewellery is a good place to start your guilloché hunt.

Make-up accessories and containers offer a rich hunting ground for beautiful enamel work, with engine turning and applied painting to the enamel.

A silver powder compact by Cartier or Ripley & Gowan (US) lush with guilloché slipped from a bag in a smoky nightclub, was a heady jewel in the hand.

Some were made to be shown off at all times, carried around on the wrist or a single finger on a silver chain. The centre panels often carry a pretty full rose or two painted over the enamelling.

Make up sets, hair-brushes and mirrors with a guilloche finish were intended to be left out on a lady’s table in her bedroom, and were a popular gift for a well-heeled bride’s trousseau.

Treat these pieces like fragile glass, cleaning with a silver cleaning cloth and storing where possible in their original boxes to avoid chipping.