Blog written by @junimargrie
Underglazes are a wonderful way to add colour, vibrancy and unique interest to the surface of your ceramic pots. There are many ways of applying underglazes to either greenware (unglazed pottery) or bisque fired ceramics (pottery that has been fired once but not glazed), and these are often then finished with a transparent glaze to seal the surface and make it glossy and smooth.
At Pottery Supplies we have several underglaze products available in our shop that can be applied in various techniques to create interesting decoration. These include the popular Deco brand that we manufacture in-house and was developed by potter Marc Sauvage, as well as Cesco underglazes from Walker Ceramics. Feel free to browse our website for products that would suit your need and give you the confidence to explore. We ship Australia wide. Your only limit is your creativity!
What are ceramic underglazes?
Ceramic underglaze products are highly concentrated colourants blended with clay, frit and a little water. They can be applied at both greenware and bisqueware stage and their colours will adhere onto the clay’s surface after firing from lower earthenware through to higher stoneware temperatures. Underglazes will remain stable in a kiln firing, so your pattern or images won’t change or move. They are a popular product to use to create colourful, vibrant surface designs on your pots.
1. Brushing
Brushing on liquid underglazes to ceramic surfaces is the most common application technique. Underglaze colours can be applied using a wide range of different brushes, from detailed fine lines to broader strokes, depending on the look you are going for. Apply 2-3 coats for a more opaque colour, and fewer coats for a more translucent effect. Underglazes can be blended with more water to create a lighter water colour look. Colours can also be blended to create a completely different palette, although testing is always recommended because the final colour may look completely different after the kiln firing! Other variables in colour can be obtained by creating pastels from adding white, or deeper colours by adding black. Again, testing your combinations is strongly recommended!
2. Sgrafitto
Sgrafitto originates from Italian, meaning ‘to scratch’. Liquid underglaze is often painted onto a greenware piece, left to dry to the right consistency (the underglaze should look matt and feel dry to the touch) and whilst the piece is still leather hard, the potter then uses a tool to scratch or carve out a design and reveal the contrasting colour of the bare clay underneath. The result is quite striking.
3. Mishima
This technique originated in Korea and involves using a tool to carve out a design or illustration into leather hard clay then inlaying those carvings with liquid underglaze (although slip, a different clay body, stains and washes are also commonly used). Excess underglaze is then scraped away with a metal rib, or wiped away with a damp, clean sponge. Smooth, fine clay bodies are best for this type of work.
4. Sponge ware
Sponge ware pottery is characterised by vibrant colours and patterns created by dipping natural or synthetic sponges into liquid underglaze then dabbing them onto ceramics pieces. Spongeware pottery pieces became hugely popular in the 19th century both within the US and Europe as a more affordable alternative to fine China, and popular colours included red, blue, brown, green and orange. Creative potters experimented with covering their pieces in various shapes and designs ranging from easy dots and lines to more complex motifs.
5. Stencils
Underglazes are effectively used in creating beautiful stencil designs painted onto the ceramic surface. A traditional method of stencilling is to adhere paper cutouts onto the surface of leather hard pottery using a bit of moisture, and then brushing coloured slip, or underglazes, over the top. The stencils are then carefully removed to reveal the design on the surface. Some potters have taken advantage of the popularity of die-cutters to create unique and interesting stencil designs.
6. Underglaze pencils, chalks, pens and underglaze tissue transfers
Nowadays underglaze products have diversified to pencils, chalks, pens, and patterns on tissue transfer paper to enable an even greater range of options. Like the liquid version, these underglaze products can be used across a broad range of cone temperatures (though some may fade at higher temperatures so always check the manufacturer’s recommendations), and then sealed with a clear glaze. Pencils, chalks and pens should be used on a smooth bisque fired surface, whereas tissue transfers can be applied onto either greenware or bisqueware. At Pottery Supplies we have a broad offering of these diverse underglaze products you can use to decorate your pieces and enhance the offering of art supplies in your studio.