Piaget

MTF
[PuristS]
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PIAGET Enamel Watches – a Fusion of Art and Science: Part 1

Ref. G0A31164 'Venice'

When I first saw 'enamel' Piaget Polo Tourbillon Relatif watches, I was rather surprised that they called it enamelling. I expected enamel work for watches to be pure white dial faces or miniature paintings on case backs. I could not understand why the monochromatic 'metal work' on the Piaget watches was called enamelling. As moderator, I had to do a bit of reading and research just in case somebody asked. 

G0A33505 'Pekin'

Ref. G0A33505 'Pekin'

I must acknowledge the invaluable assistance rendered by Piaget, British Society of Enamellers and the good old Encyclopaedia Britannica for background information about this fascinating material science. Enamel is simply glass which is ground to a powder before being fired and fused on a metal base. Suitable metals for enamelling include gold, silver, copper, aluminium, and steel. The ground glass is a combination of silica and soda ash with added metal oxides to give colour.

Enamelling is the process of fusing layers of ground glass onto metal using a kiln or torch. Firings can take from 30 seconds to several minutes, with the kiln heated between 650°C and 1000°C, depending on the techniques and materials used. Industrial, or liquid enamels are enamel frits that are ground very finely and mixed with other components to make a liquid suspension. This is applied to a metal surface with a spray gun, a brush, or by dipping.

Enamel powder is often applied as a paste, and may be transparent or opaque when fired; vitreous enamel can be applied to most metals. It has many excellent properties: it is smooth, hard, chemically resistant, durable, can assume brilliant, long-lasting colours, and cannot burn. Its disadvantage is a  tendency to crack or shatter when the substrate is stressed or bent.

Colour in enamel is obtained by the addition of various minerals, often metal oxides of cobalt, praseodymium, iron, or neodymium. The last creates delicate shades ranging from pure violet through wine-red and warm grey. Enamel can be either transparent, opaque or opalescent (translucent), which is a variety that gains a milky opacity the longer it is fired. Different enamel colours cannot be mixed to make a new colour, like paint. This produces tiny specks of both colours; although the eye can be tricked by grinding colours together to an extremely fine, flour-like, powder.

It seems to me that the process is more of an Art rather than a Science because pyrometer readings vary widely from kiln to kiln. Thus no precise firing temperatures are “universal". Enamelling on silver is very different from enamelling on copper; what is high firing on silver is probably a low firing for copper. Enamellers share information as hints about where to look for specific effects and enamel behaviour, more than Standard Operating Procedures.

The first obstacle to understanding is the language. Even the English-speaking world has to use German or French terms by convention. It was quite a while before I realised that my French tutors were talking about enamel (émail) rather than a rapid means of text telecommunication!  According to some sources, the word 'enamel' is derived from the High German word 'smelzan' (to smelt) via the Old French 'esmail'.

Piaget Grand Feu Enamels
Compared with “classic” enamels, the distinctive nature of “grand feu” enamels such as those used by Piaget lies in the fact that they reach their melting point at a far higher temperature, meaning between 820°C and 850°C. This technique makes them extremely pure and guarantees the longevity of the resulting models. Raw enamel comes in lumps or as coarse powder. During the preparation process, the material is ground in a mortar to create an extremely fine powder, which is then thoroughly rinsed. The cleaned and ready-to-use enamels are stocked in distilled water.

Enamel is always placed on a metal die mould and only copper, silver and gold feature the qualities required for this purpose. In keeping with its constant pursuit of excellence, Piaget uses only gold on all its creations. Depending on the thickness of the metal part, the latter will need to be enamel-backed. The enamel backing is extremely important, since it keeps the base in a state of fusion in such a way that it does not camber or buckle. The enameller can then apply the enamel using a fine brush and plant glue and leave it to dry before proceeding to the firing process.

Techniques of Enamelling

Pure enamel

Beauty often stems from extreme simplicity. Thanks to its extremely deep hues, enamel enables watchmakers to create models featuring exceptional finesse and understated elegance. Piaget is keenly aware of this, and even though the Manufacture is well acquainted with the various enamelling techniques, it is prepared to use it in its simplest and purest form.

Piaget Emperador Coussin
Large model 18-carat white gold case; White enamel dial, slate grey Roman numerals
Manufacture Piaget 809P mechanical self-winding movement; Limited edition of 50 pieces
Ref. G0A33016

A monochrome enamelled dial punctuated by slender Roman numerals is enough to confer an aura of nobility and strength on a timepiece. Vividly revealing the fundamentals of the art of enamelling, this process consists in applying the matter in layers, one firing after another, in order to mark the numerals and the brand logo, for example. The enameller’s know-how manages to achieve a subtle nuance in the shade of the material so as make it a perfect match with that of the watch case or bezel.

Champlevé enamelling

Recesses in the form of patterns or designs are carved or etched into the metal and the enamel is wet packed into these areas. Champlevé, French for "raised field", is where the surface is carved out to form pits in which enamel is fired, leaving the original metal exposed.

Piaget employs champlevé enamelling by engraving a motif in a metal die mould before filling the cavities with enamel. Using a drypoint (graving tool), the engraver traces the desired motif on the watch case or dial. Being careful to avoid the contours, he hollows out the various fields, thereby achieving a relief engraving featuring grooves of various width and thickness according to the desired effects, with rims as clear-cut as possible. The enamels are then applied to the crevices before being melted at over 800°C.

Such a creation calls for several firings, followed by a lapping (polish) process to smooth over the surfaces of the work and a glazing firing to give it its final appearance. Close cooperation and genuine creative complicity between the engraver and the enameller are required, since the final result will depend on both of their work, especially when using translucent enamels that enable one to view all the details of the engraving through their transparent coating.

Piaget Polo Tourbillon Relatif – Limelight Collection

In tribute to the cities of Paris and New York, Piaget created a collection linking these two cities. Manufacture Piaget presented twin versions of its Tourbillon Relatif, with detail that is reminiscent of the famous cityscapes. On the Parisian model, the dial displays the twelve avenues leading to the Place de l’Etoile in the dial centre; while the New York version features stylised depictions of the 12 tallest skyscrapers. Engraved in 18-carat white gold, they are illuminated by the contrasts of black enamel. The crown of each model bears a symbol representing the city depicted. The “Paris” version features a large Ferris wheel with a diamond at its centre. Piaget has decided to restrict production of these watches to three pieces for each city.

Reference 608P, the mechanical hand-wound flying tourbillon movement entirely designed, developed and produced within the Manufacture, sets an unusual stage for the tourbillon function. Positioned at the tip of the minute hand and thus totally mobile, it turns one rotation per minute. Its carriage featuring three titanium bridges enhances a movement decorated with circular Côtes de Genève on which the screws are blued and the parts bevelled and hand-drawn. The latter is housed within an 18-carat white gold champlevé enamelled case.

Paris dial
18-carat white gold case and dial with grand feu enamelling according to the champlevé technique
18-carat white gold and black enamelled case-back with “Paris” engraving
The dial represents an aerial view of the 12 avenues radiating from the Arc de Triomphe along with their names.

The profile at 3 o’clock represents the view of several historical monuments: the Louvre and its Pyramid, the Ferris wheel located on Place de la Concorde, the Eiffel tower, and the banks of the River Seine. The winding crown, at the centre of the Ferris wheel, is set with a diamond (0.04 ct) highlighting the beauty of the capital.

The profile at 9 o’clock shows the Jardin des Tuileries, the monument of the National Assembly, the Grand Palais, the Arc de Triomphe and the Arche de la Défense.
Numbered and limited edition of 3 pieces
Ref. G0A33044

New York dial
18-carat white gold case and dial with black grand feu enamelling according to the champlevé technique
18-carat white gold and black enamelled case-back with “New York” engraving
The dial represents a silhouette view of the 12 tallest buildings of New York. The name of each building is hand-engraved on them, completed by superlative hand-engraved finishing (more than 190 hours of work).

The profile at 3 o’clock represents a close-up view of New York from Liberty Island. The winding crown is set with a diamond (0.04 cts) in the middle of yellow gold flames. It represents the torch of the Statue of Liberty.

The profile at 9 o’clock shows a view of Manhattan with its two main bridges (Manhattan and Brooklyn bridge) on either side.
Numbered and limited edition of 3 pieces
Ref. G0A33045

Sailing dial
18-carat white gold watch with grand feu enamelling according to the champlevé technique
18-carat white gold case and dial, blue grand feu enamelling depicting a windrose with North/South and East/West indications

18-carat white gold and blue grand feu enamelled case-back with an engraved  sailboat

The profile at 9 o’clock shows a boat race lit up by the beams shining from the lighthouse.

The profile at 3 o’clock depicts a marina with moored boats.
The crown evokes the shape of a rudder. 
Numbered and limited edition of 3 pieces
Ref. G0A34045

Basse-taille

An extension of champlevé, the recesses are engraved with patterns or carved with a low relief design which can be seen as varying densities of colour through the transparent enamel. Basse-taille, from the French word meaning "low-cut". The surface of the metal is decorated with a low relief design which can be seen through translucent and transparent enamels.

Cloisonné enamelling

French for "cell", where thin wires are applied to form raised barriers, which contain different areas of enamel applied above the original metal form.
The enamel is contained within wire cells (cloisons). These wires are usually fired onto a base coat of flux (a clear transparent enamel), then filled with wet enamel. The wet enamel is often applied with quill in layers, a technique known as wet packing. The piece is fired after each layer has been applied.

Painted Enamels and Grisaille

Traditionally very finely ground metallic oxides are painted onto a white enamel base with fine brushes and fired, layer upon layer. The process, which is analogous to painting, can produce a detailed three-dimensional quality. Grisaille is painted in a similar fashion but reversed: the background is black or dark blue and the images are applied in various densities of white to give a chiaroscuro effect. Painted enamel, a design in enamel is painted onto a smooth surface. Grisaille and Limoges enamel are sub-categories of painted enamel.

Grisaille, French term meaning "greying", where dark, often blue or black background is applied, then limoges (Limoges porcelain) or opalescent (translucent) enamel is applied on top, building up designs in a monochrome gradient, paler as the thickness of the layer of light colour increases.

Limoges enamel, made at Limoges, France, the most famous European centre of vitreous enamel production.
Limoges porcelain, named after the town in France where it was invented, is the technique of "painting" with a special enamel called "blanc de limoges" over a dark enamelled surface to form a detailed picture, often human figure. It is a form of Grisaille.

Plique-à-jour

In this technique, the enamel is fired into an open metal framework, with the result resembling stained glass. Plique-à-jour, French for "braid letting in daylight" where the enamel is applied in cells, similar to champlevé, but with no backing, so light can shine through the transparent or translucent enamel. It has a stained-glass like appearance.

Ronde bosse

French for "round bump". A 3-D type of enamelling where a sculptural form is completely or partly enamelled. Stencilling, where a stencil is placed over the work and the powdered enamel is sifted over the top. The stencil is removed before firing, the enamel staying in a pattern, slightly raised.

Sgrafitto

This technique is where an unfired layer of enamel is applied over a previously fired layer of enamel of a contrasting colour, and then partly removed with a tool to create the design.

Counter enamelling

Although this is not strictly a technique, it is a necessary step in many techniques.  It is to apply enamel to the back of a piece as well – sandwiching the metal – to create less tension on the glass so it does not crack.

I hope this brief introduction to enamelling has helped understanding of the techniques used by PIAGET and also stirred interest in "Technique at the Service of Design".

Please return and join us for 'PIAGET Enamel Watches – a Fusion of Art and Science: Part 2' click here

Regards,

MTF

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