Our pottery is handthrown and Raku fired. A copper matt glaze has very little glass in it, just enough to permanently bond the copper oxide to the ceramic surface. At 970 °C the pottery is lifted from the kiln and placed on a bed of sawdust. Flames are allowed to play around the pots before covering and sealing. The colours are produced by a thin layer of copper oxide refracting light in a similar way to oil on water, using thin film interference to produce a similar spectrum of colours. The dark smoky background and flame patterns remind us of the Northern lights in the night sky.