Creating Coloured Porcelain

I have been experimenting with adding colour into porcelain slip. I've decided to colour the clay body, rather than adding a glaze or coloured slip on the surface, as I have been creating 3D textured pieces which I feel would lose their definition if I covered them. To get bright colours, quite a lot of underglaze needed to be added to the porcelain, because the porcelain is white, so all of the resulting colours would be tints.

I decided to test the colours at different temperatures as well as different concentrations of colour. Starting at 1g of underglaze to 100ml of porcelain slip, I also tested 2g, 3g and 5g. I poured out the slip onto plaster bats to dry, then cut each into 6 sections to fire at 1000, 1060, 1140, 1200, 1230, and 1260 degrees Celcius. I felt like this would give me a good overview of how the firing temperature and concentration alter the colour.

I used Picasso blue, black, turquoise, and lime green underglaze powders, and I plan to start mixing my own colours now I have a better idea of how they behave at different temperatures and concentrations. I remembered to label them before I fired them because I've made the mistake before of getting a beautiful result and forgetting how I got there!

I will make some texture tests with the coloured clay to see how the surface works with the colour, and I will also try putting underglaze powders into plastic clay rather than slip, to see if a uniform texture can be obtained by wedging it into the clay.