Auteur Topic: Niello of Email?  (gelezen 2026 keer)

appie68

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Niello of Email?
« Gepost op: november 16, 2011, 13:31:13 pm »
Gedeeltes van boeken die het verschil tussen niello en email wat begrijpelijker maken.
Bijna alle boeken zijn geschreven in het engels en zijn meestal uitgegeven door universiteiten en andere instellingen.


eerst de wikipedia:

Niello:

Niello is a black mixture of copper, silver, and lead sulphides, used as an inlay on engraved or etched metal. It can be used for filling in designs cut from metal. The Egyptians are credited with originating niello decoration, which spread throughout Europe during the late Iron Age[1] and is common in Anglo-Saxon, Celtic and other types of Early Medieval jewellery.
 
Renaissance Niello

The goldsmiths of Florence in the middle of the 15th century ornamented their works by means of engraving the metal with a burin, after which they filled up the hollows produced by the burin with a black enamel-like compound made of silver, lead and sulphur. The resulting design, called a niello, was of much higher contrast and thus much more visible. bron



Email (oude en nieuwe technieken)

The ancient Egyptians applied enamels to pottery and stone objects, and sometimes jewelry, though the last less often than other ancient Middle Eastern cultures. The ancient Greeks, Celts, Georgians, and Chinese also used enamel on metal objects.

Enamel was also sometimes used to decorate glass vessels during the Roman period, and there is evidence of this as early as the late Republican and early Imperial periods in the Levantine, Egypt, Britain and the Black Sea. Enamel powder could be produced in two ways; either through the powdering of colored glass, or the mixing of colorless glass powder with pigments such as a metallic oxide. Designs were either painted freehand or over the top of outline incisions, and the technique probably originated in metalworking. Once painted, enameled glass vessels needed to be fired at a temperature high enough to melt the applied powder, but low enough that the fabric of the vessel itself was not melted. Production is thought to have come to a peak in the Claudian period and persisted for some three hundred years, though archaeological evidence for this technique is limited to some forty vessels or vessel fragments.

Enamel was at its most important in European art history in the Middle Ages, beginning with the Late Romans and then the Byzantines who began to use cloisonné enamel in imitation of cloisonné inlays of precious stones. This style was widely adopted by the "barbarian" peoples of Migration Period northern Europe. The Byzantines then began to use cloisonné more freely to create images, which was also copied in Western Europe. The champlevé technique was considerably easier, and very widely practiced in the Romanesque period. In Gothic art the finest work is in basse-taille and ronde-bosse techniques, but cheaper champlevé works continued to be produced in large numbers for a wider market.

From Byzantium or the Islamic world the cloisonné technique reached China in the 13-14th centuries; the first written reference is in a book of 1388, where it is called "Dashi ('Muslim') 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 remained very popular in China until the 19th century, and is still produced today. 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 Japanese also produced large quantities from the mid-19th century, of very high technical quality.

From more recent history, the bright, jewel-like colors have made enamel a favored choice for designers of jewelry and bibelots, such as the fantastic eggs of Peter Carl Fabergé, enameled copper boxes of Battersea enamellers, and artists such as George Stubbs and other painters of portrait miniatures. Enameling was a favorite technique of the Art Nouveau jewelers.

Enamel may be transparent or opaque when fired; vitreous enamel can be applied to most metals. The great majority of modern industrial enamel is applied to steel in which the carbon is controlled to prevent reactions at the firing temperatures. Enamel can also be applied to copper, aluminium, stainless steel, cast iron or hot rolled steel, as well as gold and silver.

Color in enamel is obtained by the addition of various minerals, often metal oxides cobalt, praseodymium, iron, or neodymium. The last creates delicate shades ranging from pure violet through wine-red and warm gray. 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 colors cannot be mixed to make a new color, in the manner of paint. This produces tiny specks of both colors; although the eye can be tricked by grinding colors together to an extremely fine, flour-like, powder.

enamelling techniques:

* 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.
* Champlevé, French for "raised field", where the surface is carved out to form pits in which enamel is fired, leaving the original metal exposed;
* Cloisonné, French for "cell", where thin wires are applied to form raised barriers, which contain different areas of (subsequently applied)
   enamel. Widely practiced in Europe, the Middle East and East Asia.
* Grisaille, French term meaning "in grey", where a dark, often blue or black background is applied, then a palescent (translucent) enamel is
   painted on top, building up designs in a monochrome gradient, paler as the thickness of the layer of light color increases.
* Limoges enamel, made at Limoges, France, the most famous European center of vitreous enamel production. Limoges became famous for
   champlevé enamels from the 12th century onwards, producing on a large scale, and then from the 15th century retained its lead by switching
   to painted enamel on flat metal plaques.
* Painted enamel, a design in enamel is painted onto a smooth metal surface. Grisaille and later Limoges enamel are types of painted
   enamel. Most traditional painting on glass, and some on ceramics, uses what is technically enamel, but is often described by terms such as
   "painted in enamels", reserving "painted enamel" and "enamel" as a term for the whole object for works with a metal base.
* Plique- -jour, French for "open to daylight" where the enamel is applied in cells, similar to cloisonné, 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 "in the round", also known as "encrusted enamel". A 3D type of enameling where a sculptural form or wire framework
   is completely or partly enameled.
* Stenciling, 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, where an unfired layer of enamel is applied over a previously fired layer of enamel of a contrasting color, and then partly removed
   with a tool to create the design.
* Serigraph, where a silkscreen is used with 60-70in grade mesh.
* Counter enameling, not strictly a technique, but a necessary step in many techniques, 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.     bron




Niello (from Latin: Nigellus = "blackened") is a metallic alloy with sulfur which is used as a surface decoration technique which, much like enamel, is fused to a metal base. The luster of niello, however, is metallic instead of vitreous. Also, niello is much tougher than enamel. Niello comes in just one color - black of various tones - which contrasts highly with silver, the most popular base for niello work. Through the use of engraving, etching, chiseling or embossing techniques, an indentation is made in the work and filled with the black sulfide alloy. The methods used in niello are are similar to email champlevé and email de taille d'épargne, although most other enameling techniques can be used as well. Due to these similarities, niello is sometimes also misnamed black enamel.  bron


duidelijke verschillen:    Niello =  metaal, plooibaar/vormbaar , alleen zwart en variaties daarop
                                                     Email =   glas, broos, veel kleuren

¨ it is regarded as a masterpiece of niello-making if a silver plate that has been inlayed with niello can be hammered out cold until it has twice its original area without the niello cracking¨

Een klein stuk uit:     Studies in Conservation   Vol. 1, No. 2, Jun., 1953  Niello,  A.A. Moss (de rest is voor ons niet bereikbaar)
« Laatst bewerkt op: februari 09, 2012, 11:47:02 am door alberto »

appie68

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Re: Niello of Email?
« Reactie #1 Gepost op: november 17, 2011, 22:57:01 pm »
Niello en email en het middeleeuwse vakmanschap  (In het geheel staat hier veel beschreven)

Mediaeval craftmansship and modern amateur
« Laatst bewerkt op: januari 19, 2012, 12:41:48 pm door alberto »

appie68

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Re: Niello of Email?
« Reactie #2 Gepost op: januari 19, 2012, 13:05:18 pm »
Er zijn meerdere recepten voor niëllo. Deze recepten geven verschillende kleuren, die kunnen variëren van een grijs-blauwe tint tot diep zwart. De meeste bekende methode (bovendien loodvrij) is die van Plinius, die leefde in de eerste eeuw van onze jaartelling. Hieronder zijn recept:

    * 3 delen fijn zilver
    * 1 deel rood koper
    * 3 delen zwavel

Deze ingrediënten samensmelten in een aarden smeltkroesje met deksel. Deksel dichtsmeren met klei. Verhitten tot het deksel gaat rijzen. Giet het geheel na smelting over in een ijzeren gietvorm.
Voordat het is afgekoeld moet het dun worden uitgeklopt. Soms moet het tussentijds nog een beetje verwarmd worden, want als het afgekoeld is kan het niet meer worden uitgeklopt. Het geplette niëllo wordt met water overgoten, en daarna met een hamer zo fijn mogelijk verpulverd. Het poeder wordt in de verdiepingen van het zilver geplaatst. Het werkstuk wordt daarna verhit totdat de niëllo net gesmolten is. Het mag niet roodgloeiend worden. maar de juiste temperatuur is mij niet bekend.

N.B. de toevoeging van zwavel geeft het diep-zwarte zilversulfaat.

Zie ook een gedetailleerde beschrijving bij Ganoksin.
« Laatst bewerkt op: januari 19, 2012, 14:16:00 pm door alberto »

appie68

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Re: Niello of Email?
« Reactie #3 Gepost op: januari 19, 2012, 14:51:24 pm »
Voorgaande drie, en nog een paar voorbeelden met Niello:

appie68

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Re: Niello of Email?
« Reactie #4 Gepost op: januari 19, 2012, 15:21:10 pm »
Als ik heb tijd, dan word dit uitgebreid..........  :D

  enamelling a brooch

  niello en zilver
« Laatst bewerkt op: januari 19, 2012, 15:57:40 pm door alberto »