Editing Brass (section)

===Medieval period===
[[File:Renier de Huy JPG0.jpg|thumb|''[[Baptism of Jesus|Baptism of Christ]]'' on the 12th-century [[baptismal font at St Bartholomew's Church, Liège]]]]
Little is known about the production of brass during the centuries immediately after the collapse of the [[Roman Empire]]. Disruption in the trade of tin for bronze from [[Western Europe]] may have contributed to the increasing popularity of brass in the east and by the 6th–7th centuries AD over 90% of [[copper alloy]] artefacts from [[Egypt]] were made of brass.<ref>Craddock, P. T., La Niece, S. C., and Hook, D. (1990). "Brass in the Medieval Islamic World". In Craddock, P. T. (ed.), ''2000 Years of Zinc and Brass''. London: British Museum, p. 73</ref> However other alloys such as low tin bronze were also used and they vary depending on local cultural attitudes, the purpose of the metal and access to zinc, especially between the [[Islamic]] and [[Byzantine]] world.<ref name=r4/> Conversely the use of true brass seems to have declined in Western Europe during this period in favor of [[gunmetal]]s and other mixed alloys<ref>Bayley 1990, p. 22</ref> but by about 1000 brass artefacts are found in [[Scandinavia]]n graves in [[Scotland]],<ref name=r24/> brass was being used in the manufacture of coins in [[Northumbria]]<ref>Gilmore, G. R. and Metcalf, D. M. (1980). "The alloy of the Northumbrian coinage in the mid-ninth century". In Metcalf, D. and Oddy, W. ''Metallurgy in Numismatics'' 1 pp. 83–98</ref> and there is archaeological and historical evidence for the production of [[calamine brass]] in Germany<ref name="r18" /> and [[the Low Countries]],<ref>Day 1990, pp. 123–150</ref> areas rich in [[Calamine (mineral)|calamine]] ore.

These places would remain important centres of brass making throughout the [[Middle Ages]] period,<ref>Day 1990, pp. 124–133</ref> especially [[Dinant]]. Brass objects are still collectively known as ''dinanderie'' in French. The [[baptismal font at St Bartholomew's Church, Liège]] in modern [[Belgium]] (before 1117) is an outstanding masterpiece of [[Romanesque art|Romanesque]] brass casting, though also often described as bronze. The metal of the early 12th-century [[Gloucester Candlestick]] is unusual even by medieval standards in being a mixture of copper, zinc, tin, lead, [[nickel]], iron, [[antimony]] and [[arsenic]] with an unusually large amount of [[silver]], ranging from 22.5% in the base to 5.76% in the pan below the candle. The proportions of this mixture may suggest that the candlestick was made from a hoard of old coins, probably Late Roman.<ref>Noel Stratford, pp. 232, 245, in Zarnecki, George and others; ''English Romanesque Art, 1066–1200'', 1984, Arts Council of Great Britain, {{ISBN|0728703866}}</ref> [[Latten]] is a term for medieval alloys of uncertain and often variable composition often covering decorative borders and similar objects cut from sheet metal, whether of brass or bronze. Especially in [[Tibetan art]], analysis of some objects shows very different compositions from different ends of a large piece. [[Aquamanile]]s were typically made in brass in both the European and Islamic worlds.

[[File:Lion Aquamanile, 1200-1250 AD, German, Lower Saxony, Hildesheim, bronze - Cleveland Museum of Art - DSC08638.JPG|thumb|left|upright|Brass [[aquamanile]] from [[Lower Saxony]], Germany, c. 1250]]
The cementation process continued to be used but literary sources from both Europe and the [[Islamic world]] seem to describe variants of a higher temperature liquid process which took place in open-topped crucibles.<ref>Craddock and Eckstein 2003, pp. 224–25</ref> Islamic cementation seems to have used zinc oxide known as ''tutiya'' or [[tutty]] rather than zinc ores for brass-making, resulting in a metal with lower [[iron]] impurities.<ref>Craddock et al. 1990, 78</ref> A number of Islamic writers and the 13th century [[Italians|Italian]] [[Marco Polo]] describe how this was obtained by [[sublimation (phase transition)|sublimation]] from zinc ores and [[Condensation|condensed]] onto [[clay]] or iron bars, archaeological examples of which have been identified at [[Hindu Kush|Kush]] in Iran.<ref>Craddock et al. 1990, pp. 73–76</ref> It could then be used for brass making or medicinal purposes. In 10th century [[Yemen]] [[Abū Muhammad al-Hasan al-Hamdānī|al-Hamdani]] described how spreading [[al-iglimiya]], probably zinc oxide, onto the surface of molten copper produced tutiya vapor which then reacted with the metal.<ref>Craddock et al. 1990, p. 75</ref> The 13th century Iranian writer [[al-Kashani]] describes a more complex process whereby ''tutiya'' was mixed with [[raisin]]s and gently roasted before being added to the surface of the molten metal. A temporary lid was added at this point presumably to minimize the escape of zinc vapor.<ref>Craddock et al. 1990, p. 76</ref>

In Europe a similar liquid process in open-topped crucibles took place which was probably less efficient than the Roman process and the use of the term tutty by [[Albertus Magnus]] in the 13th century suggests influence from Islamic technology.<ref>Rehren, T (1999) "The same... but different: A juxtaposition of Roman and Medieval brass making in Europe" in Young, S. M. M. (ed.) ''Metals in antiquity'' Oxford: Archaeopress pp. 252–257</ref> The 12th century [[Germans|German]] monk [[Theophilus Presbyter|Theophilus]] described how preheated crucibles were one sixth filled with powdered calamine and [[charcoal]] then topped up with copper and charcoal before being melted, stirred then filled again. The final product was [[casting|cast]], then again melted with calamine. It has been suggested that this second melting may have taken place at a lower temperature to allow more zinc to be [[Absorption (chemistry)|absorbed]].<ref>Craddock and Eckstein 2003, 226</ref> Albertus Magnus noted that the "power" of both calamine and tutty could [[evaporate]] and described how the addition of powdered [[glass]] could create a film to bind it to the metal.<ref>Rehren and Martinon Torres 2008, pp. 176–178</ref> 
German brass making crucibles are known from [[Dortmund]] dating to the 10th century AD and from [[Soest, Germany|Soest]] and [[Schwerte]] in [[Westphalia]] dating to around the 13th century confirm Theophilus' account, as they are open-topped, although [[ceramic]] discs from Soest may have served as loose lids which may have been used to reduce zinc [[evaporation]], and have slag on the interior resulting from a liquid process.<ref>Rehren and Martinon Torres 2008, pp. 173–175</ref>