Ceramic Colorants

How to Make Vibrant Bursts of Color on Pottery Using Clay Slip and Ceramic Colorants

How to Make Your Clay Slips POP!

• July 10, 2020 • Read Comments (24)

clay slip

Lana Wilson uses texture and clay slip to decorate much of her work. It’s a a lot of fun to do washes of color on textured surfaces, leaving concentrations of the glaze or ceramic colorants in the recesses. But sometimes when the clay slip or glaze is washed off, the color loses its vibrancy.  To solve that problem, Lana uses steel wool rather than water and a sponge and maintains the bright color of the clay slips she uses.
 
Today, Annie Chrietzberg explains Lana’s process and shares the clear glaze recipe she uses to make her work food safe. – Jennifer Poellot Harnetty, editor.

Lana Wilson’s work is mostly black and white with bits of vibrant color splashed about. She says, “I have a background in painting, and this technique really appeals to the painter in me.” She was inspired by the work of Denise Smith of Ann Arbor, Michigan, and Claudia Reese, a potter from Texas.

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This technique comes to you from the pages of Pottery Making Illustrated.
PMI is the only ceramic art magazine in the world written entirely by potters for potters. And it shows. Experienced ceramic artists share their tips, their techniques and their information so you can avoid time-consuming mistakes and get the most out of your studio time.

Simple Clay Slip

To prepare the clay slip, Wilson takes 100 grams of small pieces of bone dry clay and adds 10-50 grams of a ceramic stain. The percentages of stains varies according to the intensity of color she is trying to achieve.

The clay Wilson uses is Half & Half from Laguna, formulated for firing at cone 5, though she fires it to cone 6. This clay body is half porcelain and half white stoneware. It’s not as white as porcelain, but it does fire white rather than yellow in oxidation, isn’t as finicky as porcelain, and works well with Wilson’s making methods. If you’re buying clay from the East Coast, she suggests a clay body called Little Loafers from Highwater Clays.

Easy Application of Clay Slip

The technique is simple. On a piece of bisqueware, first brush on black slip or one of the base colors (figure 1) then sponge it off, leaving slip in the crevices (figure 2). Then, using colored slips dab on bits of color here and there (figure 3). Remove some of that with steel wool (figure 4). “I can’t use water for this step or it will muddy the colors,” Wilson explains. CAUTION: You must wear a respirator during this stage. In the final step, she dips the piece in a clear glaze, and fires to cone 6. Through lots of experimenting, and with lots more to go, Wilson finds
that ending with a dark color on top works best for her.

figure 1

figure 2

figure 3

figure 4

 Mixing Colored Clay Slips

There are two groups of colored slips. The first group Wilson uses for the base coat that she washes off, leaving color in all the recesses. The accent slips are more intense and removed with steel wool. All stains are Mason stains except for 27496 Persimmon Red, which is from Cerdec. Add the stains and bone dry clay to water and allow to sit for 30-60 minutes so it will mix easier.

 

clay slip

 

NOTE: Stain-bearing slips applied to surfaces that come into contact with food need to be covered with a food-safe clear glaze. Because of the many variables involved in glazes (clay body and glaze fit, variability in chemical content, temperature variability in kilns, organic materials, etc.), we cannot guarantee food safety on the recipes we post. The best way to be certain is to have one of your finished pieces leach tested by a lab.

clay slip

Glaze Testing Resources:

www.digitalfire.com/services/consultants/index.php

www.digitalfire.com/services/database.php?list=labs

To learn more about Lana Wilson or see more images of her work, visit www.lanawilson.com.

**First published in 2009
Comments
  • Pete G.

    I do this with my embossed textures on B-Mix, cone 5. I paint or spray directly on the bone-dry ware, using thin oxides, earths, or other coloring materials, let them re-dry thoroughly, then gently rub off the high spots with ScotchBrite. The green ScotchBrite works OK, but I prefer the more aggressive maroon-colored industrial grade, # 7447.

    As always, be aware of the dust hazard when scrubbing off dry clay. You can do this in the bisque state too, but the effect is quite different. It works well with glazes on bisque, rather like the effect you’ll see on vintage Batchelder tiles.

  • Rocky B.

    If you find that applying the slip to bisque “pops and pocks” you can simply calcine some of the clay and substitute some of the clay for the calcined clay. That will reduce the shrinkage and improve the fit.

  • Regina G.

    I have your book Ceramics:Shapes and Surfaces, have used it as a bible, your increasing tips are endless, thank you!

  • Naush B.

    can someone please give me a porcelian slip recipe for my cone 6 brown body, gas firing. I fire in reduction and sometimes fire upto cone 10 in wood firing

    thank you

  • Scott M.

    An immersion blender [kitchen tool] does a great job of smoothing out and mixing the slip.

    I use similar techniques with Standard clay #213 cone 6 porcelain. This clay never cracks for me.

    For a clear overglaze, I use the second liner glaze from “Mastering Cone 6 Glazes” p. 97. It is a completely trouble free glaze.

  • Caroline G.

    Fantastic post. I love working with coloured slip and this has expanded my possibilies no end. Thank you.

  • Lana W.

    Yes, you can fire at cone 8 if you use cone 8 clay (Half and Half cone 5 does not successfully go to cone 8, it gets warts even at cone 7)Just use cone 8 clay and add the mason stains to bone dry clay and go for it.
    Lana

  • Lana W.

    Ben,
    My slip is simply Half and Half clay, cone 5 by Aardvark bone dry mixed with the Mason stains.

  • Ben M.

    Normally I apply slips as a thin skim like consistency to bisque ware, but these are high alumina flashing slips. Is your slip a higher silica content?

  • Lana W.

    Luci,
    Just add enough water to make a cream like consistency slip. It will mix up faster if the dry pieces of clay are smaller but sometimes I just soak them overnight and then mix with a stiff brush. I only make about 100 grams or even 50 grams only of a colored slip at a time.

    Lana

  • Luci G.

    Hi Lana, love your work, and thanks for sharing. Please let me know how much water to add to the stains and bone-dried clay. Thanks, just getting started. Luci

  • Lana W.

    Thanks, Sarah. Amazing how we can all work in clay and still find something new and exciting in the studio. But I am also amazed how many failures it often takes me to figure something out that I like.
    Lana

  • Sarah K.

    Lana,
    Your work truly is inspiring! Thanks for sharing just a bit of your knowledge. Fun, playful pieces with a feeling of softness/gentleness along with the complexity. Very soothing to the eye.
    Sarah

  • Lana W.

    Thanks, Valerie and if you want to see something very different you can do with these colored slips see the first image under current work on my webpage.www.lanawilson.com
    L

  • Valerie Y.

    I love your work, it is simple but has a depth of character and attitude that speaks volumes. Thank you.

  • Thanks so much, Lana–I’m going to try this. I haven’t done a lot of slip work, but have been trying to figure out a way to emphasize textures other than iron oxide, so this will be a great place to start.

  • Lana W.

    Lorna, Tammy, Laura and Inci,
    There is so little slip, it is just slivers of slip and not solid or thick so I have had no trouble putting slip on bisque. Lately I have been painting the whole soft slab BEFORE BISQUE with one to three layers of colored slips and then after carving and inlaying other colored slip slabs I bisque it. The first image on recent work on my website shows one of these very recent pieces http://www.lanawilson.com
    Thanks for your interest.
    Lana

  • Inci L.

    Thank you but İ can read only the quastions but do not know how to find the answers for them.

  • Tammy S.

    …same thought about slip on bisqueware popped into my head. I love the featured piece…awesome!

  • Reader L.

    Interesting technique. Since she is applying slip to bisqueware, is there any problem with fit and shrinkage? Or is it too thin to matter?

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