Colouring clay – pastel slips

This morning I opened test kiln no 3 that I fired to 1060C on Friday. The cone (06) bent at 1063C so the monitor was an accurate reading of the kiln’s temperature this time. These test pieces are a series of LF bowls thrown off the hump and painted in coloured slips then coated in an EW transparent glaze to an Emmanuel Cooper recipe:

High alkaline frit                            10
Standard borax frit                        50
Ball clay                                             30
Cornish stone                                  10

After admiring the work of Chloe Peytermann and Ben Fiess I painted a series of gouache abstract patterns in a similar palette of pastel colours then tried making these colours in slip to apply to clay.

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For the coloured slips I mixed Ball clay and China clay in equal parts then added 6% stain in primary colours: cobalt blue, red/orange and yellow. I’m disappointed with the results. 6% makes the colours soft but they’re no where close to the shades in the painting. The black slip (made with red clay recipe not stain) turned out brown and watered down while the pink is a sickly, fleshy colour although I can see it working nicely on sculptural forms. I feel a matte surface would complement the colours better – the shininess looks tacky.The colours didn’t mix as I expected either. The green turned out turquoise and the purple stayed pink.
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The flatness and precision of this decorating style bothers me but then again I’m tempted to cheat and just paint gouache straight onto bisqued clay, sticking two fingers up at Christopher Dresser’s principle of ‘Truth to materials’ in order to get better vibrancy of colour. I like the illustrative qualities you can get by painting slips and they can look stunning like on the domestic ware of Isabel Merrick, but the results are boringly predicable.

The only surface I’m happy with is the turquoise with the eye pattern below. Paring down to three colours looks more sophisticated and these cool, calming tones remind me of the seaside.

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