Recoloring a Classic: Trying New Colorants in a Classic Pottery Glaze Recipe Can Lead to Some Great Results

It’s hard not to love a good old classic glaze like a Shino or a Celadon. But sometimes you just need a change. Deanna Ranlett pushes experimentation with her students to make glaze mixing fun as well as educational.

In today’s post, Deanna explains a recent experimentation on the classic glaze Falls Creek Shino. In addition to sharing how they conducted the experiment, Deanna shares the recipes and results. – Jennifer Harnetty, editor.


In my glaze formulation classes students will often bring in glazes to explore, tinker with, and make their own. Of these recipes, the majority of what I see are the old standards most potters have used at one point. Besides already having the ingredients on hand, using an old favorite often allows a comfort level conducive to experimentation (I push experimentation to make glaze mixing fun) and if you get in a rut, adding a little fun to your palette can be a good way to get those creative ideas flowing.

Also, another benefit of these ‘tried and true’ recipes is that they have a broad fit range with commercially prepared clay bodies. The recipe I used for testing and experimenting, Falls Creek Shino, has many variations and discussions pertaining to it on the popular Clayart discussion group. Popularity on a chat site doesn’t mean you shouldn’t test, but it does mean that some common glaze faults aren’t present with a recipe that has such widespread recognition. For example, this shino fits every speckled body I’ve tried, as well as white stoneware and porcelain—I’ve yet to see any shivering in three years of testing with my students. I would encourage all potters to run acid leaching tests with lemon or vinegar, run a glaze in the dishwasher for multiple cycles, and test with freezing and thawing. This is an important step because every potter fires differently and uses glaze in different ways. If you’re ever concerned about colorants or glaze ingredients leaching, you can send your piece to a testing lab for extra security. For a small fee, leach tests are run, and you’re given a detailed report of the results.


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An important first step when exploring a classic recipe is to determine if all the ingredients are still commercially available. For our tests, the traditional Falls Creek Shino recipe called for Albany Slip—which of course, is no longer available and most potters substitute Alberta Slip. Colorants are by far the easiest way to experiment with a glaze. In an average base glaze, adding color is the logical next step because colorants can completely change a recipe’s appearance. However, if you take a not-so-average base glaze, like the Falls Creek Shino, adding color is unpredictable given the dark base color of the glaze. We tested 2%, 5%, and 10% of stains and 1%, 2%, and 4% of oxides. We found the ‘sweet spot’ for adding stains to be 5% and 2% for oxides.

In the original recipe, carved lines and texture allow the glaze to pool and collect the pretty cream color leaving the darker brown where the glaze breaks. So, in adding colorants, we were unsure if the background color or the foreground color would change. What we found is that the opacifiers allow the added colorant to float leaving the darker brown color below almost unchanged. The best analogy I can think of is of a root beer float—but instead of using vanilla ice cream, imagine you’d used a flavored, colored ice cream! Our results were honestly amazing. The tests maintained the depth and richness of the original glaze as well but allowed for the development of vibrant, opaque colors on top. Also, as a pleasant surprise, the Alberta Slip makes for a glaze that brushes and dips beautifully with virtually no settling in the bucket.

So when in doubt, or when you need a little something new in your glaze repertoire, pick up a classic and add some color!

Firing Schedule

I normally fire this glaze using the following schedule. This schedule is adapted from http://www.masteringglazes.com/.

  • 100°F/hr to 200°F (no hold unless I glazed that day then I will hold 1 hour to make sure the pots are dry inside).
  • 350°F/hr. to 2000°F (no hold).
  • 150°F/hr. to 2185°F (test to make sure this will be cone 6 for your kiln! This temperature may need to be adjusted) I use a 15 minute hold.
  • 9999°F/hr. to 1900°F (no hold).
  • 150°F/hr. to 1500°F (no hold).

Deanna Ranlett is the owner of Atlanta Clay and has been a working ceramic artist for 13 years. See http://www.atlclayworks.org.


Comments
  • Great article. I have the same question. Oxidation or reduction?

  • I am assuming that it is oxidation in an electric kiln? Is that a safe assumption/

  • My apologies – in editing it looks like I lost a crucial sentence – these glazes are ELECTRIC OXIDATION – fired with the schedule above that I adapted from John Hesselberths schedule published on his glaze book website http://www.masteringglazes.com – in the FAQ section. I have found this schedule to be useful in producing a nice break but it is not crucial – I also get nice results in my cone sitter kiln.

  • It appears that it is oxidation since the firing schedule is above.

  • Great article Deanna! Keep up the good work and writing.

  • Interesting. Thanks for sharing.
    Could someone please translate all those Fahrenheit schedules into Celsius or Centigrade ? That would be nice. Thanks. (It would also be nice if inside the articles in general both systems of temperatures were used. I know this is an American site, but the rest of the world usually uses the other system.)
    I will try some of those glazes in a wood firing kiln anyway and will omit the tin oxide as it is prohibitively expensive, at least here in Japan. Will also replace the Alberta slip with some Mashiko akako (the stuff that we use to make the kakiyu (persimmon glaze) here. Any suggestions welcomed.

  • I’m completely new to reading firing cycles but I don’t understand – “9999°F/hr. to 1900°F (no hold).” Is this correct?

  • Janine,
    the designation of 9999 degrees F to 1900 degrees F means that the kiln will be allowed to cool as fast as it is able to go down to 1900 degrees. 9999 is used whenever you want a kiln to ramp up or down to a temperature as fast as possible (rather than going at, say 100 degrees an hour, for example).

  • Nice outcome and variation …what clay and fire temp have these been fired. Thanks for Sharing.

  • Right up front I’ll tell you I am inexperienced with glazes. My question is about the Shino recipe and the addition of Tin Oxide and Zircopax. Do you use one or the other, or does this recipe require both? Please clarify for me. Thanks.

  • Hi, I tried this recipe. It’s beautiful but….. I’m not comfortable with the Lithium in the glaze because of it’s toxicity. Has anyone re-formulated it using a different material, like spodumene for instance?

  • Great article Deanna! I’ve tried the same kind of substitutions wiht other glazes…some turn-out and some not, but the experimentation and process is what I enjoy. I’m glad I read your article because Falls Creek Shino is one of the glazes I haven’t tried and I love the results you achieved. I WILL

  • It looks like you tested this on a red clay; did you also use a buff or white stoneware or porcelain clay body? Are they as successful?

    susan martin

  • Hi Terry – Lithium use is a hotly debated topic in studios and is usually kept near 5% – you could absolutely try spodumene. I haven’t tried it yet but I have done so in other glazes with good results – spodumene is a source of lithium that also contains silica and alumina so some other adjustments might be necessary when you substitute.

  • Hi Susan – yes white clay works well also – we normally use the shinos on Red Rock from Highwater or Speckled Brownstone – also from Highwater but I have tested on B-Mix and 240 from Standard Ceramics. We like the results – the only difference is that the brown break is less intense and lighter in color.

  • Wow, thanks a heap. I love shinos, so out to the studio I go. I’ll check your website first.

  • Thanks a heap. I love this post. I love shinos. Thanks for sharing.

  • In the Fall Creek Shino with no colorants or stains added were the zircopax and the tin oxide still used or only with the colorants.

  • Does the version without any colorants still have the Tin and Zircopax in it?

  • like everyone, I love these colors! Just two questions (which might be dumb questions), I’m very new to firing my own stuff and making my own glazes…
    I just got my first kiln last week!
    -Are these dinnerware safe glazes? (what is so toxic with litium?)
    – What cone do I fire the glazes to? I just have a kilnsitter where I pop the cone in and turn it on….I’m not sure if I can control the temperature changes on the kiln. Thanks so much for your help! -Kimberly

  • Can’t wait to mix up some samples and try this glaze. I am used to cone 10 reduction, so having to fire to cone 6 oxidation for my students pots has been a challenge. It has been a hard to find glazes they and I like. Thanks so much, this was really timely for me!

  • I have loved Falls Creek shino for years. Love the way it breaks brown/tan. Can’t wait to take it to another level. Thanks guys for continuing to brighten our snowy days with reasons to stay indoors. I’m also excited to try the Highwater clay mentioned. The speckles (I guess iron?) adds another dimension.

  • I have been reading Plainsman Clay recommendations to calcine a portion of the Alberta Slip when the recipe calls for large percentages.

    Are you finding this necessary in your experience with these Shino variations?

    Thank you for sharing.

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