The Appeal of Colour
|Copper Ruby glaze|
Colour can be added to pottery in many ways including body colour, underglaze, inglaze, onglaze and also as a component of the glaze itself.
In the second of my series on glaze I described how to make a white textured stoneware glaze.
Simply adding inorganic colouring oxides such as Iron Oxide to such a glaze produces colour but not always the desired colour! Carry on reading to find out why!
Raw Oxides in Coloured Glaze
|Top = Oxides in transparent glaze|
Bottom = Oxides in opaque glaze
|Copper oxide crackle glaze|
|Iron Oxide and cobalt oxide in glazes|
Organic pigments such as those used in paper printing are clearly not suitable and will simply burn away during firing
Ceramic Stains in Coloured Glazes
|Top = Ceramic stains in transparent glaze|
Bottom = Ceramic stains in opaque glaze
In contrast to raw oxide pigments, ceramic stains have been specially formulated to create a wide range of colour tones in glaze. In their manufacture they have undergone a heat process and a fine grinding process so that they are highly temperature stable and capable of being mixed together to generate intermediate colour tones. This property is highly valued by large scale manufacturers who need consistency of colour tones. However this all comes at a cost compared to raw oxides.
Onglaze and Inglaze Decoration
|Pantone Mugs showing onglaze colours|
SummaryClearly there is more to making coloured pottery than is immediately obvious. For those who want consistent colour that can be mixed to give intermediate shades then use ceramic stains either as a glaze component or in decoration products such as inglaze or onglaze colours. For those who want unpredictable but aesthetically pleasing results use oxides as a glaze component or under the glaze. Whichever option you choose using colour creatively will only add to the appeal of your pottery.
The Potters Friend
More information and other technical articles on pottery and ceramics can be found at my website The Potters Friend.
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