Raku Process and its Origins
Raku is essentially a style of pottery firing which involves quickly heating wares in a kiln normally fired outdoors. Traditionally kilns were fuelled by split wood or coal, but many Potters today use Propane Gas, as the temperature can be more carefully controlled.
Its origins of course lie in the Zen Buddhist Tea Ceremony and the humble little black and red tea bowls first produced by Chojiro in Japan. The Raku family themselves continue this tradition towards the present day. In traditional Raku ware the work is drawn from the kiln red hot and exposed to the air- doused in water or rolled in grass or leaves to cool. The effect is of a typically Oxidised surface- muted, understated – yet one of natural beauty and simplicity.
Western Raku is a total contrast. Here the wares are drawn from the kiln in the typical Raku style, with tongs, but instead they are placed in a chamber (normally an old dustbin) full of combustible materials- such as leaves or wood shavings. This then ignites and produces lots of flames and smoke! The lack of oxygen present causes a reduction process to begin.
This allows the metallic elements within the Glaze’s oxides to react. A wide spectrum of effects and variations is possible, from metallic lustres and textures to the familiar crazing and smoke blackened lines caused by the cooling process. Western Raku lends itself to experimentation – yet it still shares the same spontaneity and freedom evident in those original humble tea bowls produced in Japan.
Shaun Hall Raku
Copper Matt Method
Shaun works in both glazed Raku producing highly glossy metallic wares and heavily textured lava glazes. However, he is perhaps better known for using Copper matt slips.
This is a technically challenging and often elusive version of Raku firing. The pot or ware is coated in a thin copper matt slip. It is then placed in a kiln and subsequently withdrawn at a higher than normal temperature for Raku at about 1020-1040oc.
Instead of being plunged into a bin full of combustible materials and smokes, Shaun places the work on a circular bed of wood shavings. This causes flames to lick around the sides of the vessel. More wood shavings are sprinkled around the pot for up to 2 minutes, before a metal bin is placed over the work, sealing in the air. Wood shavings seal the base of the bin.
Depending on the size of the pot being fired- the work is then left to cool for between 10-15 minutes. A short burst of air is then let in by lifting the bin a little- and the pot is again left to cool for a similar period. This is repeated until the pot is cool enough to handle.
This burst of air allows a period of reoxidisation/reduction and dramatically causes the spread of the Copper Matt lustre and its’ dramatic colours. Vivid areas of metallic copper bloom can result- with anything possible from salmon pink, rust, gold, green blue, orange and red.
It has been described as the most challenging of all Raku firing techniques to master. Many variables can upset the outcome- from the “internal”-the kiln firing temperature reached- to the “external”- the temperature outside on the firing day. (A hot or cold day can sometimes cause a wide variation in cooling/reduction rates thus affecting colour development) Even the type of wood shavings used can cause problems. Lastly, The dramatic cooling rate and the sudden exposure of the pot to the outside air can cause firing cracks.
Despite these factors- Copper Matt Raku remains one of the most enigmatic and beguiling of all the varied and experimental Western Raku techniques. Perhaps though, it is the mastery of this technique required by the Potter –coupled with the almost fleeting transcience of colour, surface and “ other worldliness”- which lie at the heart of its appeal. Certainly a good Copper Matte pot is a stunning thing and consequently absolutely unique.
Shaun Hall has developed quite a reputation for working in this medium and –uniquely- with slab built sculptural wares. His work can be seen in two recently published books- 500 Raku by Lark/US and Handmade in Britain by Vivays- both published in 2011/12.
View Shaun’s work in our Ceramics section