De-mystifying Terrasigillata - Toolkit #5 Pru Morrison

Written by
Friday, 30 November 2018
Pru Morrison's terrasigillata techniques
Pru Morrison's terrasigillata techniques

Painting with coloured clay water: Terra sigillata or ‘Terra Sig’ if you are a cool dude or can’t spell, is not that difficult to make and use!  It just sounds complicated.

Pru Morrison’s workshop managed to remove all the sense of anxiety and mystery about the process which involves a minimum of materials: powdered clay, deflocculent, water and coloured stain.

Prue Morrison at the CAQ Toolkit Workshop
Prue Morrison at the CAQ Toolkit Workshop

Wikipedia has it that ‘The finish called ‘terra sigillata’ by studio potters can be made from most clay, mixed as a very thin liquid slip and settled to separate out only the finest particles to be used as terra sigillata.

Demonstrating the simple process of making the glaze in her naturally understated, relaxed way Pru made it seem so easy.

Pru Morrison with workshop participants
Pru Morrison with workshop participants

The most tricky part is syphoning off the middle section of a water solution of suspended clay particles that has been left for a few days to settle.

Some organisation is required to make the terra sigillata in advance before it is required and to add the stains.

But after that it improves with age! The result is a fine, evenly coloured glaze that can be matt to glossy.

Pru has used the technique for many years and had pre-prepared various coloured terra sigillata glazes which we then were invited to apply in creative ways to leatherhard tiles made for us in advance.

By the end of the afternoon a variety of colours of stained terra sig had been painted by attendees in layers on the tiles.

We spent the rest of the time experimenting with different effects, gently scratching back layers to reveal the colours beneath.

Each person experimented in their own way and it was quite amazing to see the variety of designs.

Part of the benefit of such a workshop is that members add to the discussion, generously sharing their own experience and alternative methods.

I enjoyed reconnecting with fellow members and exchanging ideas and  receiving words of ceramic wisdom.

I found Pru’s workshop worthwhile and my terra sigillata glazed tiles have now been fired and have turned out quite well!