Underglaze is a method of decorating pottery in which painted decoration is applied to the surface before it is covered with a transparent ceramic glaze and fired in a kiln. Underglazes are made from pigments derived from oxides. They do not contain the silica that creates a shiny or satin glaze and makes your ceramics food and stain safe.
The first thing you'll notice about underglazes is that in their liquid state, they look much like they will when finished! This makes designing your surface decoration so much easier. They fire to a totally matte finish if a glaze is not applied over it. A single coat of underglaze on the bottom of your work won't stick to the shelf.
There are several commercial underglaze series available in a wide variety of colors. They are sold as liquid underglazes, underglaze pencils, crayons, chalk, semi-moist pad sets which can be used like watercolors, and underglaze "carbon paper". Our local supplier, Bailey Pottery, carries Amaco, Coyote, Spectrum, Mayco, and Minnesota Clay underglaze products. Speedball also has a line of underglaze in a more subtle color range that are available online. Underglazes are mixable and dependable!
Underglaze can be used on leatherhard greenware, or bisque ware. The ways it can be used are many!
Lex accidentally threw this BIG bowl. She was going to reclaim the clay but was convinced to save it for a KCS underglaze project. Many hands always make something special!
Underglaze on Bisque
Underglaze on Bisqueware is a perfect technique for those who are also designers, painters, or illustrators. Bisqueware is a sturdy, absorbent surface to paint on, allowing you to create solid blocks of color using three coats of most underglazes, watercolor effects with diluted underglaze, or gradient colors. Feel free to layer colors over each over, and add fine lines with a brush or underglaze pencils. Unlike glazes, underglazes never move, what you see is what you get!
Left to right: Diana Fayt, Casey Taylor, Nada Spencer
Underglaze on Leatherhard Clay
Underglaze on Leatherhard Clay has some special features too!
Left to right: Sue Terrell, Emily Flynn, Tim Christensen
Sgraffito, in Italian "to scratch," is a carving technique that became popular during the Italian Renaissance in the 15th and 16th centuries. This decorative pottery technique is produced by applying layers of underglazes to leatherhard pottery and then carving off parts of the underglaze to create contrasting images, patterns, and textures revealing the clay color underneath.
Woodstock Ceramic Artist, Ann Morris creates her handbuilt totems and goddesses using a two-part underglaze process which she has shared with us!
"I use Brooklyn Red clay to make my sculptures. I love creating stamps and roulettes and using them to add texture.
When the piece is leather hard, or closer to bone dry, I paint it with 2 to 3 coats of underglaze. This creates an opaque coating. When bisque is fired, the colors become a little darker and more vibrant. The piece is then bisque fired to cone 06.
After the bisque fire, I mix up a dark wash. I usually just dilute black underglaze, but you can use dark blues, purples, or a mixture. I paint the wash over the entire piece and then use a sponge to wipe away the wash on the raised surfaces, leaving the dark wash in all the crevices and textures. This pops the textures and gives the piece an aged or worn look. I wipe some areas more than others and take care not to leave the wash on for too long, or it doesn’t wipe well.
I fire my pieces to cone 5 with a 10-minute hold."
This, like all things in the clay world, is a world of possibilities!
The simplest, most direct way to do an underglaze transfer is to paint with underglaze on thin paper like newsprint or rice paper. When you transfer the drawing it will be a mirror image, beware of lettering! Lara Duren King, the owner of DeeDee & Shark, has an informative video How To Make Rice Paper Underglaze Transfers if you're interested in pursuing this method of illustrating your work.
For the more ambitious, there is screen printing with underglaze your designs on rice paper. The beautiful bowl by Lex Feldheim (above) was made using screen-printed transfers of her own design. There are also many new small businesses producing underglaze transfers that are beautiful. A google search of underglaze transfers is great fun!
Underglaze transfers work best on leatherhard greenware, although they can be used on bisque the transfer is more difficult. Our neighbor, Bailey Pottery has a blog post explaining in detail how to apply underglaze transfers to leatherhard clay.
All the Rest!
While researching this blog post, I came across The Pottery Wheel's blog about the very same subject! Leslie has outlined 16 Underglaze Techniques and has videos of some including marbling using underglaze and shaving cream!
Underglaze is a many-layered topic. Like all things ceramic, exploring and experimenting are how to learn what you like and enjoy doing. Have fun!