Midnight Luster

April 2023 Raku Copper-Glazed Ceramics

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I’m going to do a few different posts about my April 2023 raku workshop pieces because there’s a lot of good work to share. In this first one, I will review my copper-glazed pieces!

Below is a platter, which has some texture on its surface; I imprinted an equine femur into the clay body thanks to bones I was allowed to keep using from the LSU SVM anatomy lab. I first glazed it with White Crackle, then wiped the white crackle back down so that it stayed in the impressions, and also applied it to the rim. Then I glazed over the top with Copper Sand. I thought this would impact the coloration, but the white crackle (at least at that thickness) only really affected the sheen; where it was applied the glaze is glossy rather than matte. Though it’s not precisely what I envisioned, it’s a strong piece.

Next, we have a small, leaning vase. I chose to apply wax to the rim and throat. Then I glazed the exterior with Copper Sand, keeping in mind that the glaze doesn’t stick to the waxed areas. In the kiln the wax then burns off, allowing the unglazed clay body to carbon trap the smoke from the reduction afterwards. I was planning on staining the raw clay, but I ended up holding off as the variably smoky surface is interesting in its own right. I need to actually decide, as I will want to wax the raw surface if I don’t stain it.

This is probably the biggest of my raku pieces this go-round. This vase vessel has Litho Carb on the inside and Copper Sands on the outside. (I really like Copper Sand as it’s pretty predictable in its behavior for me, which is a rarity when doing raku.) The interior lip has an abalone-like appearance!

Next, we have my “golden bowl.” This piece is glazed with Dakota Potter’s new Peacock on the interior, and once again uses Copper Sand on the exterior. One of my students kept hovering her hands above it and singing reverential “aaah” noises!

And below is my final copper raku piece of the workshop! This one is an oddball shape; I wanted to push myself to make some handbuilt, necked vessels and in doing so created this flora-inspired vessel. I glazed it with Litho Carb on the inside and Midnight Luster on the outside.

My April 2022 Raku Ceramics

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I just completed another raku workshop this past weekend, and as I was looking through my files I realized I’ve not yet published the raku pieces I made at my last one in April 2022. Clearly I should do that before sharing my latest workshop photos and products!

On my April 2022 raku workshop, I wanted to try to carbonize various plant fronds or leaves onto the surface of my pieces. This was a complete experiment, and it was mostly a failure. I tried a variety of ferns and tropicals out, and one after another, they burned away without leaving a trace. Here are some plates that I attempted to salvage after that didn’t work out. With the first, I pivoted to a sugar and horsehair application. With the second, I tried to use ferric chloride to stain the surface with plant leaves that weren’t carbonizing, but they just left those not-terribly-appealing ferric chloride splotches.

Once I realized those techniques were not working, I tried etching fern fronds onto a plate in a “baked potato” aluminum foil saggar firing; it kind of worked, but I think it’s underwhelming. Since none of those plant techniques were doing super well, I just put a litho carb copper glaze onto my final plate.

I also made a rounded crackle vessel and the glaze turned out really well, but the ceramic physically cracked due to thermal shock so it’s got that permanent asterisk associated with it.

I glazed this spherical vessel with copper glazes (Copper Sand is on the exterior and I think that’s Midnight Luster on the interior), and it came out looking like a little planet! This one’s a definite favorite.

And finally, the one plant piece that turned out beautifully and justified all the failures: this is another “baked potato” saggar firing, and the Muehlenbeckia axillaris vines I used carbonized perfectly into this vase’s surface.

I also lost a large platter-like vessel (it broke into quite a few pieces and was not salvageable) and had another plate fuse with a kiln brick and lose part of its bottom. I eventually recycled that broken platter-like piece in my rock tumbler!

Second Raku Workshop - Copper Glazes Edition

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I decided to try copper glazes again, but with some wild cards thrown in - I experimented more with unglazed negative spaces, and tested out some different types of glaze.

This first piece has “Midnight Luster” glaze on the interior and a lithium carbonate glaze on the exterior. It’s quite attractive in photo, but it did suffer from a bit of pitting, meaning the glaze pooled in some spots and it bubbled and hardened in ways that are suboptimal; instead of a smooth surface, there are rougher points within.

This next piece is interesting in that I had intended it to be a more standard bowl, but in the bisque firing process its sidewall accidentally got damaged and it was involuntarily edited into the shape it has now. I sanded it down a bit and decided to move forward with it; I can imagine that the cavity might improve accessibility to whatever is stored within!

I was pretty proud of this platter as a handbuilt piece, but unfortunately though it made it through the bisque firing unscathed it was unable to handle the temperature fluctuations of the raku firing and it sustained a crack across about 2/3 of its base. It is not salable now, but I still wanted to share the piece with you!

Finally, here is the most experimental piece of the metallic batch - I used both “Emerald Copper” glaze and a thinned out crackle glaze to create the exterior dripping decoration, and used “Midnight Luster” on the interior. The bottom of the exterior is just the result of carbon trapping in unglazed raku clay.

First Raku Workshop Pieces - Copper Glazes Edition

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Here are my copper glaze pieces! These all turned out beautifully, but let me tell you - I learned that I cannot control what I’m going to get, at least not with all the variables that were at play at this raku workshop! The local temperature and humidity, the time in transferring from kiln to reduction, the organics used, the timing and duration of any burps (adding oxygen back into the reduction environment) - each and every factor influences the final color, shine, and character.

Amusingly enough, from having surveyed some sample pieces in advance of glazing, I determined I quite liked lithium carbonate as the interior glaze and used it on the inside of all four of my copper pieces. For the lips and exteriors, I tried out a few different options - some more lithium carbonate with a touch of Molly’s banding purple, emerald copper, golden rainbow, midnight luster… and a couple of the exteriors look almost identical despite or perhaps because of my experimentation, in concert with the rest of the environmental factors! (Because the exterior glazes didn’t align with my expectations of them, I don’t remember which specific bowls got which exterior glazes.)

In this first bowl, the lithium carbonate interior is matte and relatively dull, and it provides a stark contrast to the dark shiny rainbow lip and exterior of the bowl.

This second, smaller bowl - like every bowl here - has lithium carbonate on the inside, but this time it resulted in a satin, coppery base and a high gloss, pink-and-rainbow interior side. The exterior is also high gloss but contrasts the interior with silvers, golds, and aqua hues, accented by some sooty squiggles. This is perhaps the loudest bowl, and it gives me a unicorn cupcake vibe.

Here is the third bowl! In many ways it’s the most subtle of the four, but it is nevertheless quite rich. The lithium carbonate here developed a semi-gloss interior that has a lot of variation, rings, and finely-detailed contrast. The exterior reflects some of the same color palette of the interior, but it adds some turquoise and blue into the mix and has a higher gloss.

Finally, we come to my favorite piece from the whole day! This bowl is really nice. The lithium carbonate interior here has a high gloss and is very coppery with splashes of blue and purple and finely detailed contrast. It is complemented by a high gloss dark rainbow exterior that is very reminiscent of the first bowl and pretty reminiscent of the third bowl in this post.

Though much of the reason this last bowl is so powerful is its glazing, another consideration is that it is the largest of the pieces I brought. With that in mind, I plan to bring mostly large pieces to my next raku workshop.

Which copper glaze bowl is your favorite?