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Understanding Islamic Metal Technology

by: Sonia Alexandrian

A small candlestick of cast brass inlaid with silver and gold. The shape of the candlestick and its coat of arms (possibly of the Boldu family of  Venice) indicate that it was made for export to Europe (Ht 12.4 cm.  Damascus c. 1400)

A small candlestick of cast brass inlaid with silver and gold. The shape of the candlestick and its coat of arms (possibly of the Boldu family of Venice) indicate that it was made for export to Europe (Ht 12.4 cm. Damascus c. 1400)


“ The use of pen cases of steel has overtaken scribes in our time, both chancery and treasury scribes. They pay extravagant prices for them and beautify them excessively. Brass is the most used… on account of its rarity and costliness.  It is the prerogative of the highest ranks of leadership, like the vizirate and similar ranks…Government scribes use long ones with rounded ends, elegantly shaped. They use them because they seek lightness and because they are accustomed to use scrolls in their writing”.

So wrote the Mamluk historian, Qalqashandi, (AH. 756-82/A.D. 1355-1418), of the fashion of pen cases in the age of large silver and copper inlaid bronze inkwells with lids. The modern convenience of fountain pens with their own ink-supply is also an invention of much greater antiquity.  In an early tenth century Arabic manuscript entitled   Kitab al-Mjalis wal Musa’irat  (the book of Assemblies and Discussions), written between 969 and 975 AD by  al Qadi al Nu’man Ibn Muhammad, the chief judge of the caliph Mu’izz, who established the Fatimid dynasty in Egypt in 969 AD, leaves no doubt that the Caliph refers to a true fountain pen:

The Egyptian scholar, Hassan El-Basha Mahmoud, in 1951, first noticed this and translated it:

When Mu’izz  mentioned  the pen he described its merits and regarded it as the symbol of the secret of knowledge; he then said he would like to make a pen which would write without the need of an ink-pot.

Such a pen, said the Caliph, would be self –supplying and have the ink     inside. One could write what one wanted with it but as soon as one relinquished it the ink would disappear and the pen would become dry. The writer could keep such a pen in his sleeve without fearing any mark or filtration of the ink for the ink would filter only when the pen wrote. It would certainly be a wonderful instrument and one without precedent.

In a few days the craftsman to whom the pen had been described brought a model made of gold. After filling it with ink, he was able to write with it. But as more ink came out than was needed, the craftsman was ordered to alter it. Finally the pen was brought back repaired. It was turned over in the hand and tilted in all directions and no ink appeared. But as soon as he took it and began to write, he wrote the best hand for as long as he wished and when he took the pen away from the paper the ink vanished. Thus I beheld a wonderful work the like of which I had never thought to see.”

Cast Persian pen box (OA 1891-6-23.5) inlaid with gold and silver (length 19.5 cm. In the radiograph dense areas such as the gold inlay and the tin-lead solder smeared across the base appear paler grey . The enlargement on the right hand end of the base shows traces of the cast structure and the black spots are bubbles trapped in the cast metal. The walls of the penbox are only 1.5 mm thick so the discovery that it was cast not hammered was an unexpected discovery.

The translation and interpretation of such contemporary texts have provided art historians and scholars with important source material in art historical research for analysis of style in hotly disputed matters of provenance. A case in point, the provenance of  ‘ Veneto-Saracenic’ metalwork objects. A large group of Islamic metalwork produced between the fourteenth and sixteenth centuries which display a mixture of Middle Eastern and European elements in their style and technique.

Scientists say, however, in some cases the same objects in this group were being attributed by different scholars to Cairo, Syria, West Iran and Anatolia, with no general agreement on which (if any) of these objects were made within the Venetian empire by local craftsmen imitating Islamic metalwork.

Clearly, the method of analysis of stylistic similarities in the shape and decoration of metalwork objects has limitations. Scientists now hope their work on these objects may help to persuade any lingering doubters of the Middle Eastern provenance of these so-called ‘ Veneto-Saracenic metal wares’.

Dr. Susan La Niece, a metallurgist and one of the scientists at The British Museum’s Department of Scientific Research, who have examined ‘ Veneto-Saracenic’ metalwork, as part of a larger survey of Islamic metalwork in the collections of the British Museum. Her most recent (2003) and most important article on Islamic metalworking technology, ‘ Scientific Research in the Field of Asian Art ‘ ed. Paul Jett. Archetype, London, is an overview of the manufacturing methods of all the brass vessels that have been examined for a new catalogue Metalworks from the Arab World in the British Museum.

Radiograph of a Veneto-Saracenic brass tray (OA 1957-2-2.3) diameter 40 cm. The concentric pattern of dark patches is made by the impressions of the hammer used in its manufacture. The magnified detail accentuates the traces of the worn silver inlay decoration which now is only preserved in the finely punched keying on the tray.

Radiograph of a Veneto-Saracenic brass tray (OA 1957-2-2.3) diameter 40 cm. The concentric pattern of dark patches is made by the impressions of the hammer used in its manufacture. The magnified detail accentuates the traces of the worn silver inlay decoration which now is only preserved in the finely punched keying on the tray.

Islamic brass ewer with silver and copper inlays, Mosul-Iraq, dated 1232 AD.  An image of both sides of the ewer produced on the radiographic film shows it was made up from several pieces of sheet brass, soldered together. The X-rays revealed soldered joints at the neck, handle and base as well as around the hole for the missing spout.

Islamic brass ewer with silver and copper inlays, Mosul-Iraq, dated 1232 AD. An image of both sides of the ewer produced on the radiographic film shows it was made up from several pieces of sheet brass, soldered together. The X-rays revealed soldered joints at the neck, handle and base as well as around the hole for the missing spout.

Dr. Susan La Niece explains the significance and the aim of analytical and technological scientific study of ‘ Veneto-Saracenic’ metalwork objects.

“Generally, museum displays give the impression that Islamic metalwork consists almost entirely of highly decorated brass vessels, but this is a trick of survival. These pieces have been treasured for generations. The survival of everyday, household items has been less good, as has the survival of precious metal vessels. The literary sources frequently refer to gold and silver vessels, furniture and jewellery, and miniature paintings of courtly scenes are full of such items. Islamic gold and silver objects have not survived in any quantity because of religious disapproval of burial of goods with the dead. Instead these objects were melted down for their precious metal content, or reworked to the latest fashion. Most surviving medieval Islamic gold and silver comes from hoards of treasure buried for safe-keeping by the owners in times of trouble, and never retrieved. Our knowledge of simple, utilitarian objects is also poor.”

There must have been an enormous amount of undecorated, functional metalwork essential to domestic life, such as roughly constructed water carriers and cooking pots. Few of these have survived, as they were thrown away or melted for scrap when they wore out.

Excavations of urban sites provide examples but many more excavations are needed before we can assess the range of this type of material.

The Scientific Study of Islamic brass metalwork

The British Musuem’s collections of Islamic brass metalwork are currently the subject of a detailed scientific study, the results of which will appear in a few years time in a catalogue entitled : – Metalworks from the Arab World in the British Museum by Rachel Ward and Dr.Susan La Niece. It will be published by  BM press.

The aim of the scientific study

A few of the objects include inscriptions which tell us the date it was made, the name of the patron it was made for, and, more rarely, the place of manufacture and the name of the maker. For the majority of objects, however, nothing at all is known about their origins, Stylistic similarities in the shape and decoration can be used to group these unknown pieces in relation to those about which more is known, but there are obvious limitations to this method. This is where a scientific approach is essential to the study of the metalwork. The scientific work on these objects can not only enable to define what they are made of and how they were made, but also to use this information to add to the knowledge we have of advances in metal technology in the Middle East from the beginning of the Islamic era, to study the interaction between the Islamic world and the cultures surrounding it and to identify workshop groupings.

The chief tools of the scientific research are:-

microscopy-  particularly for studying tool marks from manufacture and decoration of the vessels.

analysis – to identify the metal composition.

Radiography – to reveal the manufacture technique, joins and repairs, both ancient and modern.

Metal Analysis

The programme of metal analysis was begun a number of years ago by Dr Paul Craddock, using atomic absorption analysis (AAS) for major elements  (i.e. the ingredients deliberately mixed together by the metalsmith to make the required alloy eg. copper and zinc to make brass, and additional lead to help with casting) and trace elements (i.e impurities in the metal, which may be able to tell you about the original ore and processes it went through to be made into metal). Analytical techniques have advanced during this period and the analyses are being completed by Duncan Hook, using inductively coupled plasma atomic emission spectrometry ICP-AES). Over 300 objects have been analysed and published –
P.T. Craddock, S.C.  Susan La Niece and D.R Hook  ‘ Brass in the Islamic World’ in 2000 years of zinc and brass-BM Occasional paper 50. Revised edition 1998.

A round bottomed bowl with a tight fitting lid; brass with silver inlays and a European style shield for family arms. (OA1878-12-30, 698).

A round bottomed bowl with a tight fitting lid; brass with silver inlays and a European style shield for family arms. (OA1878-12-30, 698).


Almost all the copper alloy artefacts from the Islamic collections have been found to be made of brass, which is an alloy of copper with zinc. Only few specialised groups of objects were made of bronze (an alloy of copper and tin). A small but distinctive group of drinking vessels from Persia were made of a special bronze with an unusually high tin content (around 20% tin ) which gave the metal good resistance to corrosion-essential if they were used for acidic drinks like wine or fruit juice. Some utilitarian objects were made of beaten copper.

inlaid brass candlestick second half of  13th century. Damascus.

inlaid brass candlestick second half of 13th century. Damascus.

The use of brass rather than bronze is not surprising because tin is not readily available in the Middle East, but sources of zinc are abundant throughout Anatolia, Iran and Afghanistan. These zinc mineral deposits are predominantly of sphalerite (zinc sulphide, ZnS) with only relatively minor amounts of smithsonite (zinc carbonate, ZnCO3) compared to Western Europe and to China. This had important repercussions for Islamic brass production technology. Although metallic zinc was known from the beginning of the 16th century AD (the understanding of how to smelt ores to produce metallic zinc came relatively late because zinc boils below the temperature at which it is smelted and thus has to be condensed from a gas), there is no evidence that metallic zinc was used in the Islamic world for the production of brass. Instead brass was produced by a variation on the cementation process, a technology inherited from the preceding Roman and Byzantine civilisations. There are few contemporary Islamic descriptions of the final cementation stage, in which zinc oxide is mixed with the copper in the crucible to produce the brass, but rather more on the preparation of ore to produce the zinc oxide needed for this process. To convert the sulphalerite into a usable form it was roasted to convert the sulphide to oxide. Many of contemporary accounts describe a sublimation process in a heated, sealed container, where the fumes of zinc oxide, or tutiya in Persian, were condensed for collection onto clay pegs. This process served to purify it from the traces of other metals present in the zinc or, particularly sulphur and iron. The analysis programme at the British Museum has shown that iron content in Islamic brass is very low, but that in European brasses the iron content was generally higher. This is thought to be because zinc carbonate ores were being used in Europe, and these ores did not need the intermediate preparation stage of being sublimed and consequently they were less purified than the zinc ores of the Middle East.

Nickel, another trace level metal found in brass, has been found to have been increased sharply in the 15th and 16th centuries AD in Islamic brasses. A similar increase is seen in European brasses from the 11th century. This suggests that, from the 15th century, the Islamic world was sharing some of the more important sources of copper being used by European brass makers. This is backed by contemporary documentary evidence for trade in the Eastern Mediterranean at that period.

Decorative techniques
Much of the appeal of Islamic metalwork lies in its surface decoration. Designs were created by repousse, piercing, chasing and engraving. Repousse, – hammering the metal from inside the vessel against a firm but yielding material such as bitumen-created a relief design which could be extremely elaborate.

Piercing was particularly popular. Brass was inlaid with silver and sometimes copper and gold to add colour. Under the microscope it is possible to see the fine too lmarks which provide the keying to hold the thin sheet and fine wire inlays in place.

In addition to metal inlays, a black material was used to provide a contrasting background to the designs. This black material has clearly been applied hot and liquid as tiny bubbles are still visible on its surface under magnification. This material has been described as mastic, tar and bitumen, but no scientific identification was available until this project enlisted the help of Dr Raymond White, a scientist at the National Gallery, London. It was discovered that many of the inlays are indeed of bitumen, a black residue of crude petroleum which has many sources in the Middle East. More surprisingly, some of the black inlays were found to be of pitch, which is derived from distillation of conifer resins. This discovery has opened up the possibility of new methods of differentiating between groups of objects and the workshops.

A spherical brass incense burner, pierced and inlaid with silver.  The technique of Piercing was particularly used in the manufacture of incense burners, to decorative effect as well as to release the perfumes.

A spherical brass incense burner, pierced and inlaid with silver. The technique of Piercing was particularly used in the manufacture of incense burners, to decorative effect as well as to release the perfumes.

 

Results from scientific examination of this group of metal works has provided scientists with evidence which has been used to distinguish different workshops traditions, to differentiate between European and Middle Eastern manufacture, and to argue in favour of a Middle Eastern (rather than Venetian) provenance for them all.

  • islamic metal art
  • Islamic brass art

About the Author
Sonia Alexandrian, was born in Iraq in 1952 where she took a BA in English Literature . In 1977 she moved to London for her postgraduate work in Arabic and English translation at Polytechnic of Central London, and has lived in the UK ever since. She has taken advantage of her fluency in English, Armenian, Arabic and Kurdish to have a diverse career in translation and journalism. Her most recent work has been in designing a lecture series on “ Tribal Social History in Arab Silver” which she will be giving at Leighton House Museum, London in April 2007. She has also translated into Arabic the work, “ A Treasure House of Arab and Islamic Heritage”, which gives an overview of fourteen thousand Arabic manuscripts held at the British Library. Previous to this she covered the entire ‘Arab World Education program’ at the British Museum on behalf of the Arabic Weekly/BBC Arabic magazine, ‘Al-mushahid Assiyassi’. Sonia’s interests have not only been confined to international affairs; she has also taken a keen interest in her local area, becoming a member of the Board of Trustees for Response Community Project in Earls Court, London, since 1993.
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