Cloisonné

Cloisonnéis an ancient technique for decorating metalwork objects. In recent centuries, vitreous enamel has been used, and inlays of cut gemstones, glass and other materials were also used during older periods. The resulting objects can also be called cloisonné. The decoration is formed by first adding compartments (cloisons in French) to the metal object by soldering or affixing silver or gold wires or thin strips placed on their edges. These remain visible in the finished piece, separating the different compartments of the enamel or inlays, which are often of several colors. Cloisonné enamel objects are worked on with enamel powder made into a paste, which then needs to be fired in a kiln.

In antiquity, the cloisonné technique was mostly used for jewellery and small fittings for clothes, weapons or similar small objects decorated with geometric or schematic designs, with thick cloison walls. In the Byzantine Empire techniques using thinner wires were developed to allow more pictorial images to be produced, mostly used for religious images and jewellery, and by then always using enamel. By the 14th century this enamel technique had spread to China, where it was soon used for much larger vessels such as bowls and vases; the technique remains common in China to the present day, and cloisonné enamel objects using Chinese-derived styles were produced in the West from the 18th century.

Features
Cloisonne belongs to enamel and can also be classified as metal, but it is often mistakenly classified as porcelain.

Exquisite cloisonne products must have bright and moist colors, thick and solid fetal bones, neat and well-drawn silk, and brilliant gold plating. Cloisonne glazes are very diverse, but the most commonly used are sky blue (light blue), royal blue (lapis lazuli), red (chicken blood), light green (grass green), dark green (vegetable jade, translucent) Color), white (car channel color), grape purple (amethyst with glass texture), purple (rose), turquoise (between sky blue and royal blue, bright color).

History
The cloisonné craft originated in the ancient Near East. Nineteenth century BC has been used by ancient Egyptian pharaohs to make necklaces, which are usually used in combination with gems. The Eastern Roman Empire brought this technology to the highest level, not only created a variety of new colors, but also cooperated with precious metal processing technology to make a fuss on the copper wire that divides the glaze.

Early techniques
Cloisonné first developed in the jewellery of the ancient Near East, typically in very small pieces such as rings, with thin wire forming the cloisons. In the jewellery of ancient Egypt, including the pectoral jewels of the Pharaohs, thicker strips form the cloisons, which remain small. In Egypt gemstones and enamel-like materials sometimes called “glass-paste” were both used. The Byzantines perfected a unique form of cloisonné icons. Byzantine enamel spread to surrounding cultures and a particular type, often known as garnet cloisonné is widely found in the Migration Period art of the “barbarian” peoples of Europe, who used gemstones, especially red garnets, as well as glass and enamel, with small thick-walled cloisons. Red garnets and gold made an attractive contrast of colours, and for Christians the garnet was a symbol of Christ.

This type is now thought to have originated in the Late Antique Eastern Roman Empire and to have initially reached the Migration peoples as diplomatic gifts of objects probably made in Constantinople, then copied by their own goldsmiths. Glass-paste cloisonné was made in the same periods with similar results – compare the gold Anglo-Saxon fitting with garnets (right) and the Visigothic brooch with glass-paste in the gallery. Thick ribbons of gold were soldered to the base of the sunken area to be decorated to make the compartments, before adding the stones or paste. Sometimes compartments filled with the different materials of cut stones or glass and enamel are mixed to ornament the same object, as in the Sutton Hoo purse-lid. In the Byzantine world the technique was developed into the thin-wire style suitable only for enamel described below, which was imitated in Europe from about Carolingian period onwards.

Enamel
The earliest surviving cloisonné pieces are rings in graves from 12th century BC Cyprus, using very thin wire. Subsequently, enamel was just one of the fillings used for the small, thick-walled cloisons of the Late Antique and Migration Period style described above. From about the 8th century, Byzantine art began again to use much thinner wire more freely to allow much more complex designs to be used, with larger and less geometric compartments, which was only possible using enamel. These were still on relatively small objects, although numbers of plaques could be set into larger objects, such as the Pala d’Oro, the altarpiece in Saint Mark’s Cathedral, Venice. Some objects combined thick and thin cloisons for varied effect. The designs often (as at right) contained a generous background of plain gold, as in contemporary Byzantine mosaics. The area to be enamelled was stamped to create the main depression, pricked to help the enamel adhere, and the cloisons added.

Two different techniques in Byzantine and European cloisonné enamel are distinguished, for which the German names are still typically used in English. The earliest is the Vollschmelz (“full” enamel, literally “full melt”) technique where the whole of a gold base plate is to be covered in enamel. The edges of the plate are turned up to form a reservoir, and gold wires are soldered in place to form the cloisons. The enamel design therefore covers the whole plate. In the Senkschmelz (“sunk” enamel, literally “sunk melt”) technique the parts of the base plate to hold the design are hammered down, leaving a surrounding gold background, as also seen in contemporary Byzantine icons and mosaics with gold glass backgrounds, and the saint illustrated here. The wires and enamels are then added as before.

The outline of the design will be apparent on the reverse of the base plate. The transition between the two techniques occurs around 900 in Byzantine enamel, and 1000 in the West, though with important earlier examples. The plaques with apostles of around the latter date on the Holy Crown of Hungary show a unique transitional phase, where the base plaque has hammered recesses for the design, as in senkschmelz work, but the enamel covers the whole plaque except for thick outlines around the figures and inscriptions, as in the vollschmelz technique for examples of this technique and vollschmelz work). Some 10th-century pieces achieve a senkschmelz effect by using two plates superimposed on each other, the upper one with the design outline cut out and the lower one left plain.

From Byzantium or the Islamic world the technique reached China in the 13–14th centuries; the first written reference is in a book of 1388, where it is called “Dashi ware”. No Chinese pieces clearly from the 14th century are known, the earliest datable pieces being from the reign of the Xuande Emperor (1425–35), which however show a full use of Chinese styles suggesting considerable experience in the technique. It was initially regarded with suspicion by Chinese connoisseurs, firstly as being foreign, and secondly as appealing to feminine taste. However, by the beginning of the 18th century the Kangxi Emperor had a cloisonné workshop among the many Imperial factories.

The most elaborate and highly valued Chinese pieces are from the early Ming Dynasty, especially the reigns of the Xuande Emperor and Jingtai Emperor (1450–57), although 19th century or modern pieces are far more common. The Chinese industry seems to have benefited from a number of skilled Byzantine refugees fleeing the Fall of Constantinople in 1453, although based on the name alone, it is far more likely China obtained knowledge of the technique from the middle east. In much Chinese cloisonné blue is usually the predominant colour, and the Chinese name for the technique, jingtailan (“Jingtai blue ware”), refers to this, and the Jingtai Emperor. Quality began to decline in the 19th century. Initially heavy bronze or brass bodies were used, and the wires soldered, but later much lighter copper vessels were used, and the wire glued on before firing. The enamels compositions and the pigments change with time.

In Byzantine pieces, and even more in Chinese work, the wire by no means always encloses a separate color of enamel. Sometime a wire is used just for decorative effect, stopping in the middle of a field of enamel, and sometimes the boundary between two enamel colors is not marked by a wire. In the Byzantine plaque at right the first feature may be seen in the top wire on the saint’s black sleeve, and the second in the white of his eyes and collar. Both are also seen in the Chinese bowl illustrated at top right.

Chinese cloisonné is amongst the best known enamel cloisonné in the world.

The Japanese also produced large quantities from the mid-19th century, of very high technical quality. In Japan cloisonné enamels are known as shippō-yaki (七宝焼). Early centres of cloisonné were Nagoya during the Owari Domain. Companies of renown were the Ando Cloisonné Company. Later centres of renown were Edo and Kyoto. In Kyoto Namikawa became one of the leading companies of Japanese cloisonné. The Namikawa Yasuyuki Cloisonné Museum is specifically dedicated to it.

Russian cloisonné from the Tsarist era is also highly prized by collectors, especially from the House of Fabergé or Khlebnikov, and the French and other nations have produced small quantities. Chinese cloisonné is sometimes confused with Canton enamel, a similar type of enamel work that is painted on freehand and does not use partitions to hold the colors separate.

In medieval Western Europe cloisonné enamel technique was gradually overtaken by the rise of champlevé enamel, where the spaces for the enamel to fill are created by making recesses (using various methods) into the base object, rather than building up compartments from it, as in cloisonné.

Later techniques were evolved that allowed the enamel to be painted onto a flat background without running. Plique-à-jour is a related enameling technique which uses clear enamels and no metal backplate, producing an object that has the appearance of a miniature stained glass object – in effect cloisonné with no backing. Plique-a’-jour is usually created on a base of mica or thin copper which is subsequently peeled off (mica) or etched away with acid (copper).

Other ways of using the technique have been developed, but are of minor importance. In 19th century Japan it was used on pottery vessels with ceramic glazes, and it has been used with lacquer and modern acrylic fillings for the cloisons. A version of cloisonné technique is often used for lapel badges, logo badges for many objects such as cars, including BMW models, and other applications, though in these the metal base is normally cast with the compartments in place, so the use of the term cloisonné, though common, is questionable. That technique is correctly referred to by goldsmiths, metalsmiths and enamellists as champlevé.

A large collection of 150 Chinese cloisonné pieces is at the G.W. Vincent Smith Art Museum in Springfield, Massachusetts.

Production
The production process of cloisonne is complicated. From the technical method, it can be divided into: tire making, reeling, welding, spotting, burning blue, polishing and gold.

Tire making
Before the Qianlong period, the tire making was cast in bronze, which took a long time and had high accuracy, and was good at shaping the body. During the Qianlong period, it was changed to copper (pure copper) sculpting, so it was also called tyre, which greatly saved the consumption of copper.

Reeling
Use tweezers to flatten the thin copper wire into various exquisite patterns. Common patterns such as patterns, moire, geometric patterns, figures or animal patterns, etc.; then use white cymbals (a plant that can be made into (Vegetable glue) or flux to adhere to the copper tire, and then sieve silver solder powder.

Welding
The copper wire pattern is firmly welded to the copper tire using a high-temperature firing at 900 degrees.

Point medicine (point blue)
Enamel is an opaque or translucent gloss material that is prepared by melting and melting raw materials such as lead, borate, glass powder, etc. It adds different oxidized metals to become different colors of enamel, that is, enamel color. After cooling, the melted enamel becomes solid. Before filling, it is ground into fine powder and mixed with water. Add the enamel color powder to the solvent, call out different colors of glazes, and use a metal spatula to fill various enamel glazes into the space of the silk lines according to the outline of the lines. Highlight white.

Burn blue
Baking in a kiln, melting at 800-1000 degrees, to melt the powdery glaze. Because the volume of the enamel glaze is reduced by about 1/3 after the firing, in order to prevent the surface of the device from being uneven, it is necessary to fill it with the same color enamel multiple times. Repeating the glazing roasting twice to three or four times in this way can make the glaze surface and the copper wire level without pits.

Polished
Put the roasted utensils into the water, grind them with coarse sandstone, yellowstone, charcoal, etc. to smooth the uneven blue glaze, and finally use copper, scraper to scrape the copper wire, bottom line and mouth line without blue glaze. bright.

Gold-plated
The flattened and polished cloisonne was pickled, decontaminated, and sanded, and then placed in a gold plating solution, and the electricity was applied to attach the gold to the unglazed metal tire. The purpose of gold plating is to prevent the metal tire body from corroding and rusting, and also to increase the brightness of the utensils as new and golden. Finally, after washing and rinsing and drying, a dazzling cloisonne is completed.

Modern process
First the object to be decorated is made or obtained; this will normally be made by different craftspeople. The metal usually used for making the body is copper, since it is cheap, light and easily hammered and stretched, but gold, silver or other metals may be used. Cloisonné wire is made from fine silver or fine gold and is usually about.010 x.040 inches in cross section. It is bent into shapes that define the colored areas. The bends are all done at right angles, so that the wire does not curve up. This is done with small pliers, tweezers, and custom-made jigs. The cloisonné wire pattern may consist of several intricately constructed wire patterns that fit together into a larger design. Solder can be used to join the wires, but this causes the enamel to discolour and form bubbles later on.

Most existing Byzantine enamels have soldered cloisons, however the use of solder to adhere the cloison wires has fallen out of favor due to its difficulty, with the exception of some “purist contemporary enamellists” who create fine watch faces and high quality very expensive jewelry. Instead of soldering the cloisons to the base metal, the base metal is fired with a thin layer of clear enamel. The cloisonné wire is glued to the enamel surface with gum tragacanth. When the gum has dried, the piece is fired again to fuse the cloisonné wire to the clear enamel. The gum burns off, leaving no residue.

Vitreous enamels in the different colors are ground to fine powders in an agate or porcelain mortar and pestle, then washed to remove the impurities that would discolor the fired enamel. The enamel is made from silica, niter, and lead oxide to which metallic oxides are added for coloring. These ingredients are melted together, forming a glassy frit which is ground again before application. Each color of enamel is prepared this way before it is used and then mixed with a very dilute solution of gum tragacanth.

Using fine spatulas, brushes or droppers, the enameler places the fine colored powder into each cloison. The piece is left to dry completely before firing, which is done by putting the article, with its enamel fillings, in a kiln. The enamel in the cloisons will sink down a lot after firing, due to melting and shrinkage of the granular nature of the glass powder, much as sugar melting in an oven. This process is repeated until all cloisons are filled to the top of the wire edge.

Three styles of cloisonné are most often seen: concave, convex, and flat. The finishing method determines this final appearance. With concave cloisonné the cloisons are not completely filled. Capillary action causes the enamel surface to curve up against the cloisonné wire when the enamel is molten, producing a concave appearance.

Convex cloissoné is produced by overfilling each cloison, at the last firing. This gives each color area the appearance of slightly rounded mounds. Flat cloisonné is the most common. After all the cloisons are filled the enamel is ground down to a smooth surface with lapidary equipment, using the same techniques as are used for polishing cabochon stones. The top of the cloisonné wire is polished so it is flush with the enamel and has a bright lustre. Some cloisonné wire is electroplated with a thin film of gold, which will not tarnish as silver does.

Examples of contemporary application
Even today, various jewelry objects are made using the technique of cell melting. Some selected examples are listed here, this is an incomplete list.

An example of contemporary application of technology is the dial of the watch “The Dragon” from the “Cloisonné” series from the Vulcain brand (Le Locle, Switzerland). The blog “Uhrsachen” writes: “The partially random nature of the process with the result that each time into the reflections and the play of colors unique piece is created.”

Donzé Cadrans SA (Le Locle, Switzerland) specializes in the use of enamel for dials. They work with enamel in various techniques, including the cell melting process (cloisonné).

Another application of the cell melting technology can be found at the American motorcycle manufacturer Harley Davidson. In 1998, on the occasion of its 95th anniversary, the company launched a motorcycle series with an emblem made of enamel cloisonné. A fuel filler cap, which was produced for the Dyna Low Rider model in 2003, was also produced using this technique.

Also in the field of art there are various examples of the contemporary use of the Email Cloisonée. The artist Kai Hackemann, who lives in Germany, shows works from this technique from 2013 on his website.

Jewelry design and pearl
There are many offers for objects in the technique of email cloisonné on various online sales platforms. The aesthetics of the enamel cloisonné, characterized by the metal bridges, is also imitated as a design in inexpensive jewelry production. There are countless small pearls, jewelry boxes and objects that have a certain similarity to the technique of the enamel cloisonné, but the design and attention to detail are not comparable.

Vases
With the help of the old technology of the Email Cloisonné, new works have been created over the past decades that can be compared technically and optically with the old technology. However, this example from Beijing did not lead to a new interpretation. The vase was made in Bejing Shi in 1984 and decorated with floral patterns that stretch across the entire indigo blue vase like a network of flower heads.

Manufacturing process today
There are three different styles of manufacture:

With the concave manufacturing method, the cells are not completely filled
With the convex manufacturing method, the cells are overcrowded.
With the flat manufacturing method, the cells are filled exactly to the edge of the cell.

The Cloisonné manufacturing process can be divided into four steps: First, precious metal is bent into shape in the form of flat-rolled copper wires, placed on edge and soldered. A previously drawn decorative pattern is reproduced. This step can be compared to sketching while painting. The copper washers are two to three millimeters wide and are tweezersand small pliers bent into different shapes. Then these copper particles are attached to the blank.

In the second step, the colors are applied to the base body previously produced using a tube. The different shades of blue are made from natural ore powder that is mixed with water. The copper frame, now enriched with color, is then heated to 800 ° C in a kiln. The ore powder melts and hardens after the burning process, creating bright colors. Finally, the hardened enamel is carefully sanded and polished in the fourth step. In order to avoid oxidation of the finished product, it must also be gold-plated.

To date, Cloisonné products can only be made by hand. Mechanical production has so far not been possible because the manufacturing process is too delicate.

The art of enamel cloisonné is hardly practiced today. In China, art (Jingtailan) was therefore declared an intangible national cultural heritage by the government in 2006.