How to mimic these beautiful stone finish ceramics from Japan?

[Mmplin]

Hello, I recently came across the work of a store in Tokyo named Qusamura that sells cacti in beautiful stone looking ceramics:

 

Does anyone have any advice or starting points on how to do this type of finish that looks like a rock, specifically on slipcastings? I'm struggling to find how to get a pitted look and the organic distribution of color. Thanks so much

[Sorcery]

Did you see this "artists" page?

http://qusamura.com/artists_a/

Perhaps you can locate them and contact via email directly?

It's worth a shot.

Sorce

[Callie Beller Diesel]

It looks like the shop that Sorcery has linked to might be the Ikebana artist, not the potter. It seems like there's pots in a few different styles there, so they are likely sourcing from multiple potters.

As far as those surfaces go, I think there's how they were produced, and how we might approximate that under the conditions you've specified (slipcasting, and assuming an electric kiln). You haven't mentioned a firing temperature, but I'll assume you mean to fire at cone 6. None of these surfaces are a result of glaze alone: the clay body is going to play a big part of surface development. You may be working uphill by starting with casting slip, and if you mean to fire lower than cone 6, that will complicate things further. It can be done: but there may be added steps to get an organic look. It will take some experimentation, probably with some non-standard materials.

It's hard to tell with the resolution, but I think the middle one is probably woodfired, and looks like a firebox or bag wall pot: lots of wood ash accumulation on a clay body that looks like its got some kind of added sand or coarse feldspar. To get that look on a slipcast piece, I'd look at layering a stony matte blue glaze with something like lynettes opal (runny, lots of zinc), and maybe add some kind of iron slip or incorporate some wood ash in patches. Something to give it irregularity and texture.

The look on the left seems like it's again very clay body dependent, but I can't tell exactly what's going on there. This is purely speculation, but it looks like there's some kind of fluorescing going on there. It doesn't appear to be anything as formal as a glaze, because there's no evident foot ring or break where there's a different finish on the bottom. It could just be a piece built with a short iron bearing clay that's had various oxide washes (titanium? zircopax?) applied to it. It won't be an identical look, but you could look up lava glazes.

The one on the right: I've seen some reduction atmosphere barium mattes (handle with care) break burgundy and yellow. You could try layering  a subtly textured surface with different terra sigilata colours.

[Mmplin]

Thank you Sorcery for the web link (didn’t even know they had a site!) and thank you Callie for taking the time to write out starter methods for all those finishes. I’ve been trying to figure out how to make ceramics like this for a while now and have been so frustrated hitting a wall but now feel like I have tools to get experimenting again. Thank you very much, it is so appreciated!

[Chilly]

Please report back, and let us know how you got on. 

[JohnnyK]

Having spent many years as a photographer working with Photoshop, I can truly say that nothing is as it seems...with that in mind, what about the possibility that these are not made from clay, but may be bowls made from a porous stone like real lava rock? We can reproduce almost anything with clay (does "trompe l'oeil" ring a bell?) but sometimes things actually are what they look like...