Last Saturday was the opening of our exhibition at Sarah Wiseman Gallery in Summertown, north Oxford. I met Sarah Spackman many years ago at a craft fair and she bought some of my pots to paint. Then, when we were both demonstrating at Art in Action at Waterperry Gardens near Oxford, we swapped a painting for some pots. For the Dialogues exhibition, I made some bottles inspired by Giorgio Morandi’s still life paintings and Sarah included them in some of her new paintings. I particularly like the painting below which includes some of my bottles and a plate of cherries. Sarah trained at Camberwell and loves painting still life compositions with hints of bright colour.
Earlier in the year we visited Sarah’s studio in Oxford and bought a painting. Sarah has shelves of pottery and objects which she arranges in still life compositions. She likes likes to paint fruit or flowers in season, often from her allotment or a friend’s tree.
The exhibition continues until 30 September. You can see the exhibition catalogue here.
During our summer holiday in Cornwall we had a lovely walk along the SW coast path from Perranporth to Portreath, passing several abandoned mines and spoil heaps, great places to look for rocks and minerals.
We started our 12 mile walk at Perranporth, south of Newquay on the north Cornwall coast. At Cligga Head, we passed an abandoned tungsten mine, where they mined wolframite, a black mineral containing tungsten, iron and manganese. There was also a lot of greisen, decomposed granite, on the first step towards becoming china clay. While the granite mass was solidifying 300 million years ago, hot gases caused it to decompose. It is now easily weathered by the rain and sea and we could see white granules of quartz everywhere under the heather. The hot gases forced the granite up through cracks in the older Devonian slate rocks and caused minerals to dissolve and reform in seams. The ends of mine shafts can be seen in the cliff face, which is stained red with iron oxide.
Rocks and pebbles found on our walk. Bottom right, altered granite; the large white crystals are feldspar. Bottom left, turquoise rock stained with copper. Middle left, red rock stained with iron oxide. The black rocks and pebbles are Devonian slate (400 million years old), with white veins of quartz running through them.
At St Agnes head, there is a granite outcrop which has been weathered into a clay and sand deposit where clay is dug for the Leach Pottery. Further along the coast path is the remains of an old tin mine, Wheal Coates, where the chimney of the Victorian pump engine house still stands at the top of the cliffs. Tin ore was found in seams below sea level, and so water had to be pumped from the mine shafts. We tried throwing a rock down one of the old mine shafts and it took a very long time to hit the bottom.
We also had a lovely visit to the Leach Pottery in St Ives, where we were shown round the working studio by trainee potter Lexie Macleod. The potters use a mix of St. Agnes clay, ball clay from Devon and iron oxide to give the dark, toasted colour they want. They use several glazes, a green ash glaze, black tenmoku, a dolomite white and a white/orange shino. They often throw a hundred mugs in a day, which then take several more days to finish and add handles. Their outlets include Seasalt, who fund an apprentice, and David Mellor in London and Sheffield.
I went to Bath at the weekend, walking from Bradford on Avon along the canal, then through a mile long railway tunnel cut into the limestone. In Monkton Combe we passed the house of William Smith, who made the first geological map of Britain in 1815. The map shows the white streak of oolitic limestone which Bath is built of. The limestone was formed during the Jurassic, by small, round accretions of calcium carbonate deposited at the bottom of a shallow sea. Either side of the limestone are layers of mudstone and fuller’s earth, a type of calcium rich bentonite clay. William Smith put money into a Bath stone mine, which unfortunately produced only inferior stone and he had to go to debtors’ prison. He was not recognised until old age as the father of British geology.
During the walk, we noticed many wild flowers which grow in chalk soils, including Bath asparagus, ornithogalum pyrenaicum, which only grows in seven counties but is common around Bath and Bristol. The shoots used to be eaten as asparagus. In the grounds of Monkton Combe school, we saw bee orchids, ophrys apifera, which look like little brown bees with pink wings.
In the Monkton Combe village churchyard was the grave of Harry Patch, the last surviving soldier of the First World War, who died in 2009 aged 111.
I was interested in how the underlying limestone has affected the landscape, the flowers that grow there and the birds and animals. During the walk we heard chiffchaffs, saw a kestrel carrying a mouse, passed ducklings and dragonflies, as well as yellow irises, purple hedge woundwort and pink geranium pyrenaicum, hedgerow cranesbill.
We went through a very long, dark tunnel through the limestone hill, walked across Bloomfield Green and ended up in Bath, the city made of beautiful Georgian houses of cream coloured limestone.
Last week I took part in an exhibition on Marks and Tools put together by Design Nation at Oxo Tower Wharf. The curator was Liz Cooper, who brilliantly pulled together all the work from 23 different makers and designers. Interiors journalist Barbara Chandler wrote an online showcase about the makers and their tools. As well as ceramics, glass, textiles and furniture, there were photographs of all the makers using their favourite tools and talks from textile artist Margo Selby, glass blower Michael Ruh and ceramicist and printmaker Hannah Tounsend. Other exhibitors included Anna Gravelle who makes tufted textiles, Gillies Jones who make beautiful glass bowls and furniture designer Hugh Miller. What I loved about the exhibition was that it showed furniture, tableware, textiles, lighting and wall pieces together as you would have them in your home, rather than the way they are usually separated into different categories in museums. Design Nation bring together designers and makers from different areas, encouraging collaboration and innovation.
I am excited that my next book Science for Potters is coming out soon. The cover shows a pair of Atomic Bottles by Kate Malone, covered with atoms and crystals. The book will cover chemistry, geology, clay, crystals, the science behind colour and glazes. For anyone who would like to know a bit more about the science of pottery.
Colouring oxides are added to glazes to produce colour. They dissolve in the glaze to produce transparent glazes with more depth than those made using commercial stains. I prefer to add only small amounts of colouring oxides to give pale, watery transparent glazes.
The glaze recipes are in my book The Handbook of Glaze Recipes. The book shows how to make a wide range of subtly coloured glazes predominantly using the colouring oxide rather than commercial stains.
My next book Science for Potters is coming out later this year.
Earthenware glazes are made mostly of frit, which is a kind of man-made feldspar. Borax, soda and other water soluble materials can be made insoluble by heating together with silica. The resulting glass is ground up and used together with clay and silica to make low temperature earthenware glazes. Frits are also used to lower the melting temperature of mid-range glazes. The raw mineral borates are found in dried up lake basins in Turkey and California.
Opacifiers can be added to make the glaze opaque. Tin oxide is the most effective opacifier but zirconium silicate is less expensive.
A respirator mask should be worn when weighing dry materials. The dry powders are added to water and left to slake before sieving.
Stoneware and porcelain glazes are made up of at least four ingredients: silica, feldspar, whiting and clay. This is what they look like in their raw mineral forms. Silica is ground flint or quartz, usually from sand or sandstone. These are large pieces of milky quartz from a vein in igneous rock.
Silica has a high melting temperature. In order to melt in a kiln, it needs a flux. The main flux in stoneware and porcelain glazes is feldspar, found in granite, an igneous rock composed of the minerals feldspar, quartz and mica. This piece of granite from Devon has both muscovite (silver, sparkly) and biotite (black, crystalline) mica. The dark vein is mafic rock, high iron and magnesium. Granite forms when molten magma cools and solidifies. The darker minerals solidify first, then the feldspar and finally the quartz, often in large veins running through the rock. Slow cooling, deep in the earth’s crust results in large crystal size.
Clay contains both alumina and silica and is added to increase viscosity to prevent the glaze from running off the pot when molten in the kiln. Clay also helps to keep the heavier quartz and feldspar suspended in water in the glaze bucket.
Calcium carbonate added in the form of whiting is an extra flux which helps to stabilise the glaze and can also produce a matt glaze surface. Whiting is ground up chalk or limestone.
Over the last few months I have been solidly making tableware for restaurants, first 160 matt white plates for Luca in Clerkenwell, then 300 pieces including cake stands, plates and shallow bowls for Jamie Oliver’s Barbecoa Piccadilly. I have developed a routine. I make forty plates every Thursday, turn them on Friday, fire them over the weekend and glaze them on Monday and Tuesday. I have been doing this for about three months, sometimes making two batches in a row so that the heat from the kiln firing of the first batch dries out the second batch in the warm studio. I delivered the plates to Luca in November and to Barbecoa in January. I am really looking forward to going to the opening of Barbecoa in February and sampling the afternoon tea.
I have been asked to teach several glaze courses in 2017.
A new pottery school is opening in Forest Row in Sussex. I will be teaching glazes there 0n 17-19 February 2017. Contact Katrina Pechal on 0789 444 7938. You can visit the school when they open in December, courses start in January with tutors including Stephen Parry and Ruthanne Tudball.
The founder Katrina Pechal says, “ I am saddened to see so many high-level ceramics courses around the country closing. My days training at Camberwell School of Art were inspiring, having lessons with famous potters like Takashi Yasadu, Colin Pearson and Ewen Henderson among others was a great privilege and I want the next generation of potters to have the same opportunities. I have noticed a recent increase in the popularity of pottery, thanks in part to the BBC’s “The Great Pottery Throw Down. I feel this is a perfect time to move to a bigger site with better facilities where I can help students to train and develop their craft”.
Forest Row School of Ceramics will be based in the Rachel Carson building at Emerson College, set in beautiful grounds within walking distance of the village. It offers outdoor space, which Katrina needs for a kiln site (a kiln-building workshop run by Joe Finch, Potter and author of Kiln Construction (a brick by brick approach), is already planned for early next year). Emerson also has more classrooms Katrina can utilise as she expands plus affordable student accommodation it needed.
Forest Row is three miles from East Grinstead in Sussex, situated next to the idyllic Ashdown Forest yet within easy access of the M23/M25 and a short drive from Gatwick Airport, the South Downs and the creative hub of Brighton.
I will also be teaching colour in glazes at West Dean College on 5-9 March (the course is now full but you can try the waiting list), and demonstrating throwing and glazes all weekend at the Scottish Potters’ Spring Workshop at Tulliallan on 10-12 March.
For anyone in London there are glaze courses at the Morley College in February and April but I will not be teaching them.
Exciting news: I will be teaching a glaze course in Belgium in 2018.
If you can’t come on a course, you can still learn from my books.