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Copper Reds

“There is so much more to a beautiful copper red than meets the eye. Beneath what appears to be a simple rich red glaze, lies a minefield of chemistry, failure and success. This, along with the glaze’s centuries old history, steeped in tradition and ceremony, has captivated me from the very beginning.”

Elusive Copper Reds

One of Ian’s specialties and passion is for the rare and visually captivating copper red glaze. The glaze known during the Ming Dynasty as xianhong (‘fresh red’) and later dubbed sang de bouef (oxblood) in the 18th century, gets its name from its glossy, opulent, blood red appearance.

 

Copper Red glazes are among the most beautiful in the ceramic world and one of the most notoriously difficult to consistently achieve.

 

The story of the evolution of the copper red phenomenon is complex and steeped in rich cultural expression and tradition.

 

The copper reds of the Chinese Ming Dynasty (1368 – 1644) have become the most celebrated examples of this glaze, however the use of copper to provide bright red colours is actually a Middle Eastern discovery – probably from Mesopotamia, approximately 3,000 years prior to the glaze’s first appearance in China. (Wood 1999, p169)

In the evolution of pottery in China, copper was second only to iron in its significance as a colouring agent in glazes. Where it differs however is in the way Chinese potters deliberately added copper to the base glaze as a colourant, whereas iron was often present naturally in raw materials at levels high enough to colour the glaze. (Wood 1999, p167)

 

Wood (1999, p169) suggests that the copper red glazes of China have undergone a lengthy evolution that began over 1000 years ago. Also referred to as one the ‘sacrificial glazes’, they reached what was considered their pinnacle and most successful expression in the early 15th century AD during the Xuende period. During this time, Jingdezhen porcelains with copper red glazes were used for imperial rites – perhaps the most prestigious role for ceramics in China’s history.

 

During the late 15th, 16th, and early 17th centuries, there was a notable decline in the production of the xianhong glaze, the reasons for which remains a mystery. While some suggest that the decline could be attributed to a scarcity of a crucial raw material, others propose that the general frustration stemming from the unpredictable behaviour of the glaze might have played an equally significant role. (Wood 1999, p180)

Reference: Nigel Wood (1999) Chinese Glazes, G+B Arts International, London

Ian Beniston - Sensei Pots - Copper Reds

Technical Aspects

Creating consistent, high-quality copper red glazes is a multifaceted pursuit, and for Ian, it’s the intricacy of this challenge and the ultimate outcome that makes the process immensely rewarding. The spectrum of colour depth and richness is vast, ranging from vibrant, sought-after bright blood-red hues when fired to perfection, to lackluster reds or even muddy browns, humorously dubbed “mule’s liver” by the Chinese, if crucial firing elements are overlooked.

 

Firing copper reds, a brief overview:

 

  • Fired up to 1300 degrees Celsius within reduction atmosphere, where the kiln is deprived of oxygen, thereby influencing the interaction between copper and other components of the glaze and the clay body.
 
  • In reduction firing, specific gases form, altering the chemical composition of copper. It is this interaction that yields the desired red colour.
 
  • Achieving a successful firing necessitates meticulous control over firing conditions such as temperature, atmosphere, and duration. Even slight deviations can lead to failure in the desired outcome.

Mythology

Numerous ancient myths surround the origins of many glazes. Among the pottery world's most esteemed glazes, copper reds hold a particular mystique, with its myth told in various captivating if not conflicting renditions.

As one myth is told, the imperial potter made a kiln-load of pots using a copper-based glaze. On opening the kiln, the potter discovered luscious rich red pots which became the obsession of the emperor. When trying the replicate his efforts to appease the wishes of the emperor, he failed time and time again. In sheer despair at the thought of displeasing the emperor, and at the risk to his life and potential imprisonment, the potter jumped down the flu during a firing, coming to an unhappy end. His colleagues on opening the kiln discovered perfect copper red pots. Unknowingly the potter’s actions by blocking the flu, starved the kiln of oxygen, creating the reduction atmosphere required to produce copper reds.