Cloisonné Primer
by Woodrow Carpenter
Vol. 14, No. 3, June 1995
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     In the late '20's, a small enamel tray, made in China, introduced us to the word cloisonné.  The material looked like the granite ware in our kitchen.  Obviously the wires were used to keep the colors separated.  Then, cloisonné was enamel with wires separating the colors.  Simplicity, pure and simple.  This is where the majority of the general public leaves the subject, little knowing or caring about its rich history.

     Cloisonné is a French word meaning to be compartmentalized, be cut off from one another, to feel cut off, or shut out.  According to Garner¹ the term goes back to the eighteenth century.  He did not provide an exact date or indicate who first used the term to describe the finished enamel or technique.  Barsali² tells us Theophilus used "Correolae" for the cells or compartments.  Harper's New Monthly #344, January 1879 states during the fourteenth and sixteenth centuries what is now called simply cloisonné was called "esmaulx de plique" or "emaux de plite".

     Traditionally we think of cloisonné as thin strips (usually rectangular in cross section) of metal bent to form the outline of a design and fastened to the surface of a metal object, either by soldering or a coat of enamel.  The resulting cells (cloisons) are then filled with enamel.

     Researchers agree the technique originated in Egypt prior to 1800 B.C.  Gold ornaments were inlaid with small pieces of turquoise, lapis lazuli, carnelian and garnet, the inlays held in position by ribs soldered to the gold base.  Speculations are goldsmiths and glass workers collaborated to forge or imitate these works using artificial gems.  First, pieces of colored glass were substituted for the stones.  Some appear to have been cemented in place.

     In the April 1989 (Vol. 8, No. 2) issue of Glass on Metal, Dr. Panicos Michaelides wrote about six, thirteenth century B.C. rings found in Kouklia, a small village in southwest Cyprus.  In August 1989, David Buckton presented a paper at our conference describing the process used in making the cloisonné inserts in these rings.  First, an open framework or grid was constructed by soldering together gold strips.  The framework was then placed into the bottom of a cavity in a mold (probably soapstone).  The cavity was such that a round disk would be produced.  The gold strips used for the framework were not as wide as the depth of the cavity, thus the framework did not extend to the top of the cavity.  The cells of the framework were filled with colored glass powder.  Finally, a different colored glass powder was put in to fill the space around and above the framework.  After firing, the disk was tipped out.  The result was cloisonné on one side and plain glass on the other side.  This technique was used straight through to the eleventh century A.D.

     Near the end of Mr. Buckton's presentation, he showed a slide of a late thirteenth century piece of so-called email de plique, which today we know as cloisonné.

     It was inevitable that at some stage, someone would run out of cement and try to fuse the glass insert by heating.  And, of course, we know someone discovered glass powder could be fused directly to the metal.  Progress by fortunate accidents and the genius of crafts people looking for shortcuts is the main ingredient of progress.

     The word cloisonne is used to identify the technique as well as the finished product.  The cloisonné technique does not presuppose the use of enamel.  We have seen above the technique originated with gems rather than enamel.  Alexander and Gerber³ mentions wired snuff bottles with no enamel, cloisons filled with lacquer and others with acrylic plastic.  In 1868, Tsukamoto Kaisuke⁴ was the first to apply cloisonne wires to pottery and fill the cells with various colors of glaze.  Harper's New Monthly Magazine, p. 211 mentioned above, describes a method which seems questionable in some respects.  Day⁵ describes a more feasible description.

     Several authors, including Susan Benjamin, Marian Campbell, Lewis Day, and Reynold Higgins consider filigree a variation of the cloisonné technique.  It consists of wires soldered in patterns to a background.  The wire may be arranged singly, in twists, or in plaits, and they may be plain or beaded.  According to Higgins⁶, the Royal Tombs at Ur, of about 2500 B.C., produced filigree work of an advanced kind and the crude beginning of granulation.  The Russian and Hungarian wire enamels seem similar.

     Several authors, including Benjamin, Campbell and Day consider plique a jour a variation of cloisonné.  Both Benjamin and Campbell refer to it as backless cloisonné.

     The reason or function of the wires is an age-old subject for discussion.  Originally, the reason may have been independent of the function.  Originally, the reason had to do with the goldsmith being accustomed to making sockets for jewels out of upstanding strips of metal soldered on and afterwards bent over the edges of stones to hold them in place.  He was in the habit of soldering on cloisons for mosaics of precious stones and glass inlays.  And, perhaps the patron would not accept it any other way.  Later, the artist would see the value of the metal line and take it into account in the design.  The artist continues to do so even though, today, the wire serves no other function.

     The function of the wires is less obvious, a bit more complicated, and more argumentative.  Metalworkers are familiar with solder melting and rapidly spreading.  They are familiar with how much care must be taken to keep it from running to unwanted areas.  It is natural for the metal worker (and others) to believe enamel does the same.  The single fundamental difference between glass and other inorganic material is:  GLASS PRODUCES A VISCOUS LIQUID.  Enamel cannot melt - its viscosity reduces with temperature and spreads only slightly at the correct fusing temperature.  The use of cloisons to keep the colors separate has been greatly exaggerated.  With the glass available and the primitive firing means the early enameler had a difficult time getting the enamel to gloss out, let alone run very far.  The early enamel would barely fuse at 850°C (1562°F).  If an enamel design is over fired to cause spreading or slumping, the entire design slumps, leaving the boundaries intact.  This is easily demonstrated by placing a section of millefiore on an enamel surface and heating sufficiently to cause slumping.  The design elements retain their proportions regardless of how far they slump.  The millefiore technique dates from the twelfth dynasty (2000-1788 B.C.)

     The function of the wires 3500 years ago was to counter the low expansion of the early enamels.  Of course, the expansion of the enamel must always by less than that of the metal in order for the enamel to always be under compression.  However, when the differential is too great, the enameled piece will warp excessively as it cools, causing the enamel to crack and chip off.  Silver has the highest expansion of the three common metals (gold, copper, silver) used as a base for enameling.  It is no surprise there is little mention of silver enameling during the early years.  The earliest known cloisonne on copper is of the 10th century A.D.⁷

     Gold, having the lowest expansion of the three metals, along with its high ductility, was the only possibility in the beginning.  Even then, the success was possible only on small pieces.  And that is what cloisons did - divided the object into a number of small enameled pieces, joined by un-enameled metal.  In addition, the cloisons added strength to the metal shape, reducing the warpage, which in turn reduced the cracking and chippage of enamel.

     We have never seen an example, however, Day⁸ states, "In the rendering of the human face, where exceptionally broad surfaces of unbroken enamel occur, cloisons have actually been used, only they are shallower than the rest, and are covered up by the last coat of enamel."

     Our information about the compositions of enamel used throughout history is limited.  We do not know exactly when enamel, with suitable expansion, was available to eliminate the need for cloisons.  Richter⁹ reported the compositions of some 14th century Basse Taille enamels which, from our calculations, would have coefficients of thermal expansion well in excess of 300 cm/cm/°C x 10^-7.  This is sufficient to make cloisons unnecessary.  The availability of enamels with this value of expansion would also contribute to the success of the so-called painted enamel technique developed in the 15th century.

     The prestige and mystique of cloisonné is perhaps due to being the first technique to be developed to full beauty, long before other techniques.  It is easy to see why many would think this is the true way of using the material. 

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References:

1. Garner, Sir Harry.  CHINESE AND JAPANESE CLOISONNE ENAMELS.  Faber & Faber, London, 1976, p.15.

2. Barsali, Isa Belli.  EUROPEAN ENAMELS.  Cassell, London, 1988, p. 9.

3. Alexander, W.F. & Gerber, D.K.  CLOISONNE EXTRAORDINAIRE.  Wallace-Homestead Book Co., Des Moines, IA, 1977, p.11.

4. Kuwayama, George.  SHIPPO - THE ART OF ENAMELING IN JAPAN.  Far Eastern Art Council of Los Angeles County Museum of Art.  Catalog of Exhibition, Feb. 5 - Apr. 26, 1987, p.26.

5. Day, Lewis F.  ENAMELLING.  B.T. Batsford, London, 1907, p.147.

6. Higgins, Reynold.  GREEK AND ROMAN JEWELLRY.  University of California Press.  Berkeley and Los Angeles, 1980, p.22.

7. Ref. #5, p.22.

8. Ref #5, p.64.

9. Richter, Rainer.  Between Original and Imitation:  Four Technical Studies in Basse Taille Enameling and Re-enameling of the Historicism Period.  THE BULLETIN OF THE CLEVELAND MUSEUM OF ART.  Vol. 81, No. 7, September, 1994, pp.222-251.