In ceramics I have begun making my own clays, I don’t like the effect of glazing, but I still wanted to use colour in my piece, so I have made several coloured clays. So far I have made 4 bags of clay, each 3kg in weight. Different chemical powders create the colour. So far I have used, iron oxide, manganese dioxide, black iron oxide with yellow ochre and rutile with red iron oxide. I’m not sure what the outcomes will be yet, but they should all be neutral, warm shades of brown, yellow, cream and red.
I will test the colours in different firings, reduction and oxidation as I will get different colours for each. I have also experimented with marbling, I think it could give an interesting effect putting two to three colours into the extruder at a time and seeing what comes out, I like the idea of each piece being uniquely different. Recently I found that my clays weren’t holding together as well as they should and cracking with pressure so I found that adding bentonite gives the clay elasticity which has strengthened my clay, I think leaving the clay for a week to two weeks also lets the clay mature more.
I still need to experiment more with different colours I want to make at least 4 clays and use red iron oxide and yellow ochre on their own and maybe both together to hopefully produce an orange. The mixing of two coloured clays creating a marbled look is called Agateware,
‘Agateware was made in England between 1725 and 1750, and the earlier pottery was salt glazed, while the later were just covered with a colourless lead glaze. The pottery was made by mixing different colours clays or different colours of slip. In the first method the different coloured clays are usually laid in slabs, one on top of the other and beaten out to form a very big mound of clay in which the colours are mixed all together. The other method is easier to combine because it is basically clay mixed with water, making it very easy to pour. The different colours are poured together, but it is not mixed, instead a stick is pulled through maybe in a figure eight and then the slip is poured in a mould.’ Pottery Magic.
Thomas Perry uses this technique in his thrown and hand built pieces, 
‘My own pleasure is derived from the process of forming a vessel while the clay can be shaped, joined, cut, and carved. I utilize white stoneware and porcelain clays because they produce smooth surfaces and respond well to colour in glazes, under glazes, and slips and also to colour within the clay itself. I often mix oxide and commercial stain colorants into these clays to integrate layered and patterned combinations with wheel-throwing and hand building. Slicing and carving into the swirling surfaces of the wheel–thrown vessels exposes variegated patterns resembling mineral and rock cores, wood grains, and exposed stratigraphic earth layers, while stretching clay slabs during hand–building distorts and expands original patterns into new designs. The result is always a surprise and reminds me of the geological processes the earth undergoes to produce the clays and glaze materials I employ. Exploring forms with the coloured clays feed new ideas for forms with single–colour clays, and vice–versa, always linking my creative cycle to history, tradition, and the earth.’ Thomas Perry. 
