Slip, Glorious Slip

Ah slip. I think that I am in love with it. I love how it’s really, well, messy. In it’s most simple form, slip is just clay that has had water added to it. And if I used a pale coloured clay then most likely this would be how I would make my slip.

But for most of my pottery I use dark coloured clay bodies and as I would like my slips to contrast with that clay body, I have to find a different solution. So I make my own slip. Essentially it is made from different versions of the mineral, clay. I’ve tested many recipes; I’ve tried slaking down a porcelain clay, buying powdered porcelain clay, adding various fluxes to help the slip ‘move’ with the clay, and adding nothing. Finally, I am happy with where I am at with my slip recipe. It seems that it behaves pretty well. For some of my pottery I keep it thick and brush it on, and for others I add water to it to make it more pourable, and dip and pour the slip.

 So why slip? I’m not quite sure how it started, but now some of my motivation comes from wanting to give the surface decoration of my pots the quality of ‘depth’.  It’s a bit hard to describe what this is in words but I think that depth is a way of describing the surface of a pot, which through qualities such as colour, opacity and texture gives the pot a richness and vitality. In my pots the slip is one of several layers (others being underglaze colours, oxides and glaze) which I think helps to achieve this character, all contributing to giving the pot a personality.

 Perhaps this is a particularly pertinent issue when using electric kilns for firings. With other types of firing, it is easier to produce obvious depth as the surface itself is affected so heavily by the firing process. But this is not the case with an electric kiln.

 I also think that I liked the idea of some of the techniques and processes that you can use with slip. For example, using resists with slip¹, and ‘Slip and Sgraffito’ ² as decorative techniques. I realised that I could introduce colour to my slip by staining it and create brightly coloured pots without the need to make multiple glazes. And this is where my Midsummer Flower collection sits – it is my version of  slip and sgraffito pottery. At the time that I was developing this kind of pottery, I didn’t understand glaze chemistry, so it was perhaps the wrong solution to a problem that I was experiencing.

 Looking broadly at the picture of where my ceramics sit within the various pottery traditions in the UK, there is a tradition of English Slip Ware, with red coloured clay bodies and slip trailing, historically in Southwest England and Staffordshire. However, the bright coloured surface decoration is created through firing to lower, earthenware temperatures, and in the past they used lead in the glazes (which doesn’t happen now as we all know that lead is not good for human health).

Here are some examples of old English Slip Ware pots: https://collections.vam.ac.uk/item/O148499/tyg-unknown/?carousel-image=2007BN0968 for a tyg mug, and here for a Thomas Toft plate: https://fitzmuseum.cam.ac.uk/explore-our-collection/highlights/C207-1928. And nowadays there are lots of potters using these techniques to inform their work, like Russell Kingston, Clive Bowen and his son, Dylan Bowen.

However, I have always been a strong advocate for the durability of stoneware pottery. Stoneware pottery simply doesn’t chip as easily as earthenware ceramics and is less porous because it is fired to a higher, stoneware temperature which means that the glazes integrate with the clay body.  Both issues are important to me when thinking about the practicality of making pottery for use in the home.

 So, if I am not to make earthenware pottery in the English slipware tradition, then where do I look?

To Korea, and Buncheong ceramics. And this will be the subject of my next blog…

¹           this is where you can use wax or paper to prevent the slip from adhering to selected parts of the pot so that a pattern can be created

²           this is where you apply a slip and then scratch through the slip to uncover a different colour, thus creating a pattern.