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Published Jun 28, 2023

underglaze recipe

Unlike many of us, Asa Oloffson uses her own underglaze recipe so that she can create the colors and the characteristics she is after in her whimsical work. After laying down a design using a wax resist and slip inlay technique and then bisque firing, Asa paints with underglazes as if coloring in a coloring book. Finally she selectively glazes with glazes that will enhance certain colors and make them run.

In this post, an excerpt from the Pottery Making Illustrated archive, Asa shares her process and her underglaze recipe. - Jennifer Poellot Harnetty, editor

Adding Color - Underglaze Recipe

After bisque firing, it’s time to add color to the pattern (1). I use homemade underglazes (see underglaze recipe), commercial stains, and glazes mixed with oxides and I apply them with paintbrushes and foam stamps. Commercial stains are sturdy and may run a little bit if you want that effect. I apply some colored glazes on top of some of the underglazes to enhance the colors. Oxides are more likely to run than stains. And I do want it to run! That gives a softer, livelier look to the pot.


1 Add drawn designs using colored underglaze. Checkered apples are made with a fine liner brush.2 Dots are added to fruit forms using a foam stamp. Try various-tipped tools to create unique patterns.3 Fill smaller areas with broad strokes of a single color. This will allow the viewer’s eye a place to rest.4 All of the yellow underglaze is covered with an iron-rich glaze to make it run and brighten the yellow.

Within each outlined shape, I like to be creative with additional patterns. This highlights certain shapes and also allows some elements to pop while others sit more in the background, again, leading to a more harmonious overall design (2, 3). Paint an iron-rich glaze over all of the yellow underglazed areas to make it run and brighten the yellow (4).

Partially cover the handles with a copper glaze to make them green (5). A partial covering allows the texture and a bit of the slip to still show through. Brush a copper glaze (made from a transparent glaze base) over the black-slipped design elements so they bleed green (6).

Finally, the plate is dipped in a commercial clear glaze and fired to cone 04 (1940°F (1060°C)). I glaze it all the way around the bottom as well, then I fire it on three triangular kiln stilts/sticks (7). You can grind off any remnants of the sticks after the firing, so only small marks remain.

5 Brush a transparent glaze over the handles to enhance their textures and give them a similar color palette.6 Brush over the black slipped parts with a copper glaze so they bleed green. The glaze is made from a transparent glaze.7 Glaze the entire form with a clear glaze, then set it on three kiln stilts in the kiln so it won’t stick to the shelf.
**First published in 2017.