Pottery Video of the Week: How to Mix, Decant, and Troubleshoot Terra Sigillata

There’s nothing quite like the subtle sheen of Terra Sigillata. That sheen, along with the beautiful combination of both vibrant and pastel colors, is why just I love the surfaces of Jeremy Randall’s work.

In today’s post, an excerpt from his DVD Slabs, Templates, Texture, and Terra Sigillata, Jeremy demonstrates the mixing and decanting process for terra sigillata and shares the terra sig recipe he uses. Plus, he demonstrates how to test sig for specific gravity to make sure you get it just right. – Jennifer Harnetty, editor.


This clip was excerpted from Slabs, Templates, Texture, and Terra Sigillata, which is available in the Ceramic Arts Daily Shop!

To learn more about Jeremy Randall or to see more images of his work, please visit http://jeremyrandallceramics.com/.

  • Wonderful vıdeo for us way down in Turkey where we cannot go to workshop. Thank you but I want to add color but how ? Oxite or stains.? Please let me know by email because I cannot read the others answers to the questions. İncilakay@yahoo.com or Perlitasays@yahoo.com

  • Maria C.

    I finished all my bases with a red t sig in the past …i always made it up heavier, ..was happy with it but this is interesting..are you layering it on to get a good application for buffing? Thanks.

  • Reader L.

    Ditto on the question of how much colorant you add and the method of doing so. Also how do you apply your sig?
    Thank You for a great video otherwise

  • Donna K.

    It was not clear how far down the clay water mix was taken before you stopped siphoning off. You said you just wanted the middle part and it was somewhat clear on how far done the bucket the tube went but not how much of the top was discarded. Hope that question is clear.

  • Anne M.

    Thanks Jeremy! I love your surfaces and i terra sig. I have also had dumb luck making t.s. without measuring the specific gravity of my mix, but I will do so now that I know how. I have questions too! When I have tried adding colourants to my ts I have lost the sheen. Are there ones that work best, and how much do you add? Are there ones to avoid? Also, are you using earthenware, and if so, what cone do you fire to?


  • Naghmeh S.

    very complete and greatttt!!!!!!!!

  • Naghmeh S.

    very complete and geartttt!!!

  • Jill K.

    Thanks for this video, very helpful. I have made some terra sig from some clay dug out of the bank. Will have a go at testing the ratio see what I find.

  • Ginny C.

    Jeremy, that’s a great demo, very clear! But I don’t use dry clay! Last fall I tried making a small amount of t.s. from my slop bucket slip, adding water and a bit of sodium silicate. It seemed to work, but maybe that was dumb luck! I’d like to know more about making it from wet clay. Maybe I need to buy a good scale so I can at least test the specific gravity. Any suggestions?

  • Ricardo L.

    Excellent video Jeremy!!! Can you explain how to add color to the Sig? Can I use oxides? must I grind oxides in a mortar? Thanks

  • Lisa S.

    How much colorant do you add to your batch of sig?

Enter Your Log In Credentials
This setting should only be used on your home or work computer.

Larger version of the image
Send this to a friend