 When I began working in ceramics all those years ago (the 1970’s!) I can recall being disappointed, first in high school and then in college, at the “lack” of color in the available glazes. We all had our boxes of crayons bursting with color, and even the cheapest mass-produced consumer goods were glaring with color. Even today, consumer goods (even foods) are bursting with artificial color. We inhabit mostly a built environment (how often are you out in nature?) where a cacophony of accidental color prevails. For example, I’m thinking of a very tastefully designed lounge, with all the furnishings and carpets and such color coordinated-inhabited by people sporting all kinds of colors, carrying bags and things with even more crashing colors that were most decidedly not a part of the designer’s scheme. I think we learn to ignore all these clashing colors as some kind of self-defense mechanism.  I have to admit, it could be age. But it could also be looking at lots of great pottery-Bernard Leach, Shoji Hamada, Michael Cardew, Phil Rogers, Matthew Blakey and plenty of works by unknown potters in museums-I’m coming to appreciate the palette of winter. It’s like a palette cleanser for the eyes. For me, the browns aren’t neutral. Some are russet, some cool, some tawny, and these browns are punctuated (some days) with blue sky, and evergreens wearing their dark green winter coats. And when it snows, the blue sky is replaced by white, silver and a range of greys as varied as the browns they cover, to varying extents depending on how much it snowed. Don’t get me wrong, I still love the deep saturated colors of medieval stained glass, for example, but I’m also appreciating the subtle symphony of colors that winter offers.
Even as a child I loved drawing bare trees, fascinated by the spooky dark trunks and branches, the more gnarled the better. But the NCC East 40 is mostly meadow. The mountains, ocean and even forest that I always tended to associate with “nature” just are not there. Much like the winter palette of colors, which I’m enjoying more and more, I’ve come to appreciate the subtlety of the forms of the meadow. Today a new revised reprint of Bernard Leach’s classic tome “A Potter’s Book” arrived. This edition has color versions of most of the pottery examples, and they are very much in keeping with the winter landscape. Right now I’m perfectly content to inhabit the colors of winter. 
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I knew I wanted to use gold on my ceramics before I even knew why! Real gold will evaporate, “volatilize” is the technical term, if exposed to the high temperatures needed to fire the clays that I use. I confirmed this the hard way, three years ago I embedded some tiny bits of gold foil around the rim of a pot, and even in the preliminary “bisque” firing (not as hot as the final glaze firing) the pot emerged from the kiln without a trace of the gold. You’ve probably seen fine china that has gold trim or accents, for example around the edges. The way it’s done, is that you glaze and fire the whole thing first, without the gold, at the usual high temperature. Then, you apply the gold and fire at a much lower temperature to “fix” the gold permanently onto the ceramic. This is what’s called an “overglaze,” and what I finally got around to doing!
With wood firing, you can’t control exactly how anything is going to come out, and honestly the serendipity of it is a huge part of the attraction. But sometimes a piece comes out of the wood firing and, well, needs some help. Well, I had some pieces that just needed a little oomph, a little spark, an accent.Two of them had a lovely, ivory colored satiny glaze surface; but they were to subtle, they needed an accent, some pop. On the other end of the spectrum, I had a piece with a kind of mottled surface, mostly quite dark. Finally, I had a piece that had quite nice “flashing”-effects of the fire on the clay, which highlighted the sculptural form really well-but the surface was quite dull and matte, no shine.
 Opening up a wood kiln is like unwrapping Christmas presents-you may have an idea what to expect, on the other hand, you can get some real surprises! What I find the most strange, is how difficult it can be to figure out if the surprises are good or bad. It can take months, even a year or more to really “digest” the serendipitous effects off flame, wood ash and the myriad variables of the firing.
I had two sculptural, medieval inspired vases in the kiln, both had a salt-white glaze, and came out weirdly brown speckled. My first response was yuck, not what I had hoped for-and not what I had got from the same clay and glaze combination in Previous wood firings in the same kiln! In fact, there was another vase in this firing, same clay, same glaze, but it was a re-fire from the previous firing. In that previous firing, there were parts of the kiln that just didn’t get hot enough to properly melt the glaze. But this time, that pot came out with a kind of lovely glow-I’m so glad I re-fired it. But what of the two speckle monsters? Hmmm. Not so sure about those, have to sleep on that for a few months.  Then there were the mug re-fires. These were all made from “C Body” East 40 clay, and had been through a 6 day anagama firing this past October. They too must have been in cold spots in that firing, the glazes were rough and underfed. This is a clay I formulated less than a year ago, so I’m keenly interested in putting it to the test in every way possible. I had pieces in the Peter’s Valley anagama firing, in locations of the kiln that got up to cone 11 (the clay was formulated for cone 10) and there was no trouble at all. No flaws of any kind in the clay. There were also no flaws after the October 6 day anagama firing-but this re-fire kind of “fried” them, since they were located in parts of the kiln that overshot the firing range of this clay body. Let me explain.
We used cone packs that had two cones below our target, (cones 8 & 9) our target cone (10) and a “guard” cone of 11. In the photos, the order from left to right is 8,9,10,11. In the first photo, you can see a perfect 10.The number 10 cone (third from left) is making a perfect arc, the tip down to the level of the base. There is daylight under the arc, as there should be. By contrast, the lower temp cones 8 & 9 are no longer an arc, they are a puddle, and cone 11 is only beginning to bend. In the second cone pack, there is no daylight anywhere under these cones, even cone 11 is a melted puddle on top of the clay that held the cones in place. What this means is that in that section of the kiln, we blew past our goal of cone 10, and because 11 is a puddle we must have actually hit cone 12. I found out the hard way the upper limit of the C body clay; it was fine at cone 11, but cone 12 was just too much. One of them cracked early enough in the firing that the glaze hadn’t melted yet, since, the glaze healed over the crack completely. Another had little bloat bubbles. The work had been over-fired enough to become so brittle that several of them had chips that broke off the bottom where there was no glaze to support the clay. To be fair, they were really close to the firebox, which hit at least two cones above our target, as explained above. And in spite of the flaws in some of them, others have no visible flaws and they certainly didn’t melt into a puddle or even slump, which can happen when a low-fire clay is high-fired.
I fired an odd little piece I had done as a demo for texturing slabs, and making a draped form with visible slab joins from them. On the inside I sprayed on the East 40 ash glaze (that I formulated) in a fairly thin layer, and the outside was a combination of two different shinos and a salt white glaze and a little bit of the East 40 ash. For a little throwaway pot-I was going to just recycle the clay after the demo, but decided to keep it to just to experiment with glazes-I’m surprised at how good it looks.
In short, the work I cared most about-the medieval inspired vases-came out just whatever, while the piece that took me 10 minutes to make came out great. Or at least that’s what I think today. Maybe I’ll wake up in 6 months and have a totally different opinion. Please comment and let me know what you think! Please note: these videos take a while to load. (Having technical problems and don't have enough hours to throw at solving them right now) The burn ban was finally lifted, and on December 18 we finally began the firing. The two anagama firings I did in August and October went on for 5-6 days; but this firing was scheduled to be completed in just over 24 hours. To get the work “fully cooked” meant that we had to actually reach higher temperatures in the kiln than would be the case if we were firing over many days. The cones behind the removable bricks were our only way we could be sure when the work in the kiln was fully “cooked.” The heatwork needed to achieve cone 10, our goal, is considered to be 2,381 degrees. That level of heatwork can be reached by more time at over 2,100 degrees, but for a one day firing we were going to need all 2,381 degrees to get cone 10 to bend over. Gabby Gentile and Connor McGaughran (my student worker at ESU) had been there since 2 in the afternoon, and stayed with me well past their points of exhaustion until after Dave Graham (Kiln Building Guru) was able to join me. With two fireboxes needing to be stoked every few minutes, this was a skeleton crew. It was after midnight that Gabby and Connor finally went home, and it was just Dave and I for the rest of the night, until the end of the firing the next morning. I took the left firebox, and Dave the right. It’s crazy how kilns have a personality, and how two fireboxes that should be identical, one right next to the other, can behave so differently. The left side of the kiln runs colder, the coals don’t burn down to ash fast enough, so the left firebox can get so choked with coals that it restricts the needed airflow on that side. How much, what size and what kind of wood to put in, and when, are decisions that are constantly being made. You don’t just chuck wood into the kiln and hope it works; this too is an art. Pine combusts faster, but doesn’t have the staying power of hard wood, it’s kind of like a sugar high, you either feed soft wood constantly or it can crash. Hard wood can actually make the temperature drop while it’s trying to combust. Likewise, the thinner the wood is cut, the faster it catches fire-and burns out. Getting the right mix of types and sizes of wood, how much room you leave open in the firebox, how often you stoke-all this has to be right, or the kiln will let you know. There’s a wonderful “roar” when a kiln is really hot, and it’s happily digesting just the right amount of wood.  Sunrise at the East 40-one of the perks of doing all-nighter's at the kiln is getting to see the sunrise The night was beautiful. It would have been cold being out all night like that, but the kiln generated so much heat that being so close, I didn’t need most of the layers of clothing I had brought. The wind was going in the right direction, I think it actually helped us. Pyrometers that measure the air temperature in the kiln are not terribly accurate at the higher temperatures, but they do let us know if the kiln is getting hotter or cooler, which is critical information for figuring out when to stoke for example. As the kiln heats up, everything wants to expand. I’m glad Dave was there when one of the steel tie rods holding the kiln together popped under the pressure! Wow, that made me jump. He had just replaced the tie rod above the one that broke, and assured me it would be fine. You could see the other tie rods bow with the pressure the kiln was exerting as it expanded, but they held. Even if we hadn’t had the pyrometers, as in olden times, you can really tell when a kiln gets up to those higher temperatures well in excess of two thousand degrees! At 9 something in the morning, Cone 10 had made it’s perfect arc on the top right, and both cone 10 and 11 weirdly were bending together on the bottom left; we got to our goal. Once we reached our cone 10 goal, we stuffed the fireboxes as full as we could get them, then shut off all access of air to the kiln. Kilns go crazy when you do this! Any tiny sliver of space, around a brick, around a door, the flame tries to reach out, gasping for oxygen. That’s when you walk around the kiln-any gaps anywhere become really obvious with flame shooting out of them! The “door” of the kiln is temporary, rebuilt for every firing, so flames shooting out from there are not a problem. But if places that should be tight open up, this is when you find them. The fire just burns itself out, smothers-then you have to wait, and wait, for it to cool down. The bigger the kiln, the better insulated it is, the longer it takes. This post is already way too long, so you have to look at my next post for the unloading!
 Cone packs that will measure the "heatwork" achieved insidethe kiln at various locations A delightful part of my part-time job as Manager of Ceramics at the Northampton Community College (NCC) East 40 is firing the wood kiln there! I had fired that kiln a number of times before, but for this Fall’s firing, I took on more of the work than in previous firings. I made the cone packs, for example, and made more of them than we had ever used in a single firing. Cones are scientifically formulated to bend over at very specific levels of “heatwork.” Heatwork is a matter of both time and temperature. The example I always give is lasagna. The oven may be 400 degrees, but if you only leave the lasagna in for five minutes, it’s not going to be cooked through! On the other hand, even if the oven is only 350 degrees, if you leave it in for 40 minutes it’s probably going to be fully cooked. Cones measure to what degree the ceramic is “cooked,” much like how a meat thermometer measures the temperature of the meat itself, not just the air in the oven.  The kiln fully loaded. Note the two fireboxes below the "ware" chamber where all the work is stacked, and the cones placed on various shelves in the kiln. There was a cone pack for almost every shelf, so we can tell afterwards how hot each region of the kiln was It was the first time I actually got to load a wood kiln, which takes a surprising amount of skill, not to mention hoisting really heavy silicon carbide shelves into place. All the hours I had spent watching others load wood kilns was invaluable. The idea is to understand how the flame moves through the kiln, and much like playing pool where one ball bounces off another, you want to bounce the flame onto all the pots, ideally send the flame everywhere, reaching every pot without restricting the path through the kiln. No pot can touch, or even get too close to touching, yet you have to do a kind of Jenga where you get as much work into the kiln as possible. The way ash moves through and lands on the work is another consideration. Suffice it to say it was an honor, and I was holding my breath that certain decisions I had made would work out! For example, Kelly Allen noted that no one had ever put the center shelves as far to the front as I had. Yikes! I was hoping for better flow through the kiln, more ash, but what if it just meant that the work closer to the front door didn’t get hot enough? Gulp.
The door for the kiln gets built for every firing! First, the bricks. I actually really enjoyed custom fitting the last brick at the top of the arch, you can see it’s a lighter color than the bricks next to it. In previous firings we had done two bricks that stick out beyond the others, so you could remove them and see the cone packs strategically placed in the kiln for that purpose. For this firing, in addition to the two “peep” bricks, a third one with a hole in the middle was set up as a “blow hole.” Long story short, when flame is no longer coming out of the blowhole, you know it’s time to stoke. After the bricks were in place, Gabby Gentile (professor at NCC) and I “mudded” the door, which is pretty much like it sounds, although we used wet reclaim clay, not the kind of mud you have in a garden. Nothing like hands wet with “mud” in the winter. Then, for extra help so not so much heat escapes from the “door,” a special high-temperature cloth that looks like cotton but is not flammable, supported with a wire mesh was placed over the door. The pots were all loaded, the kiln was ready; but we had to leave it like that for weeks waiting for the burn ban to be lifted.
 The Anagama kiln at Peter's Valley School of Craft-left, in the day, the same at night. Even without the added eyeballs and horns, the anagama kiln at Peter’s Valley would look like a dragon. It only gets fired once per year, it takes a lot of wood and a lot of people power to fire this 57 foot long kiln-and that’s exactly what I was up to for this past week. As I write this, the kiln is cooling down, I will post again after the unload which is coming up this Sunday.  A view of the interior of the kiln during loading; the very back section is already loaded here, but this gives you an idea of the interior, which is embedded into the hillside. I worked nights, and hung out during the day as much as I could when I wasn’t sleeping. The workshop was led by the Tara Wilson, an amazing artist with a trove of woodfire experience. Charlie Lid was on overnights (among a lot of other things), a veritable brain trust who has fired this kiln 22 times and made repairs to it. The staff at Peter’s Valley is awesome, all in all it was a great group of people. From loading to finishing was all interesting, but my favorite part was the overnight crew firing the kiln. Each night got hotter, and the last night was just nothing short of magical. We were giving the kiln exactly what it wanted (with Charlie’s interpretations) and it responded. In a few hours, we side-stoked over 900 pieces of wood, and that not counting what was put in the main firebox at the mouth of the kiln. There was music on, and all of us at some point were literally dancing; there was so much joy, we were dancing with the kiln. It’s an experience I will never forget.   View of the back of the kiln. The damper is resting on bricks only inches from the ground, but even at the sides where the damper is right on the sides of the kiln, the flames hungry for oxygen are finding their way out. It’s hard to come up with words that describe the sheer power and elemental force of the flames within the kiln, that on that last night refused to be contained by the lids on the stoke holes, or the damper at the end of the kiln. Note that in the above photo and video, there is nothing “open” on the kiln; there are lids on the stoke holes and a big solid damper covering most of the end of the kiln-but the fire was so powerful that after we would stoke, it would erupt like a volcano from the slightest of gaps.
 Getting the yellow out; the yellow liquid that is not permanent goes through the cloth which is being used like a filter, but the blue woad pigment, which is a solid, gets captured in the cloth. I harvested more than on June 19, but I used about the same amount of water when I processed it. This led to a super-concentrated batch, which of course led to new discoveries. More on that later in the post.  Dipping the scarf in the woad after adding alkali but before introducing oxygen, which turns it from a dye to a (solid) pigment. I decided after adding the wood ash (to bring the PH up to 10) but before pouring it back and forth between the buckets (to oxygenate) to dye a bamboo rayon scarf. As is usual with both woad and indigo, when the vat is reduced (low oxygen) it’s a deep green, and so is the fabric when you first pull it out. But then when exposed to air (oxygen) it turns a true blue. In the case of fresh woad leaves like I was using, there is a significant amount of fugitive yellow in the leaves; and when I dyed the scarf, I had done nothing to get rid of that yellow. In any case-the scarf ended up a really lovely blue; so lovely it’s tempting to just keep it as is. But of course I’m curious about what if…I’ll get to that later. But now onto getting rid of the fugitive yellow.  At left, the color of the infusion after removing the leaves. At right, the same liquid after adding the alkali and exposing it to oxygen (by pouring it back and forth from one bucket to another.) After dyeing the scarf, I did the pouring back and forth to oxygenate the infusion of woad leaves (I had already taken the leaves out, it’s like making tea.) Woad and indigo are actually pigments, that is, a solid; dye penetrates fiber, indigo and woad coat the fiber. When I used a higher water-to-woad ratio to make the “tea,” (see my last post) the heavier, solid pigment sank to the bottom, and the yellow liquid could be scooped or siphoned off the top. But this batch was SO PIGMENT HEAVY that the pigment didn’t settle at all-even after sitting overnight! I just went ahead and tried to strain it; normally, again, the yellow goes through the cloth and the blue pigment gets trapped on top of the filter cloth. But the “waste” water after I strained the liquid (first photo at the top of this post) was not yellow-it was really dark. Obviously there was a lot of pigment left, so I strained the “waste” water a second time. Sure enough, this second straining captured plenty more pigment on top of the cloth. Doing a more concentrated batch seems to be a great way to avoid lifting larger, heavier buckets! However, it means that the pigment won’t settle, and has to be strained at least twice.  I’m kicking myself for not also dyeing a fabric swatch in addition to the scarf. That way I could cut the swatch in pieces, and try different stuff with the pieces to make comparisons. I wonder if next time I process woad, I gave the scarf an additional dip, if that would make the color deeper? I have this strange suspicion it wouldn’t do much! My reasoning is that there was SO MUCH pigment in that water, it was so concentrated, that the reason it didn’t go darker is chemical, not WOF (weight of fiber) to woad pigment ratio. So the second thing I want to do, is take some of the purified pigment, and reduce it again to make a dye vat, and then re-dye the scarf. My prediction is that without all the fugitive yellow still mixed in, the color of the fabric will go way deeper. Now I have to do another batch of woad, and put my theories to the test.
One last observation, woad is definitely a cut-and-come-again plant. The woad out at the NCC East 40 is happy that I’ve been persistently pulling the weeds to give it more room. Today-one day after I harvested the woad I’m showing in this post-you can’t even tell that I just harvested yesterday!  From left to right, the woad after ph was brought up to 10 and the liquid aerated. It looks green at left because the woad pigment, which is a solid, has not settled to the bottom. The other photos moving to the right are as more of the pigment settled; at right, I'm removing the clear yellow liquid with a turkey baster. Last year I had a bunch of empty flower pots and thought what the heck, let me see what happens if I grow woad in a small flower pot in my backyard-which does not get great sun. I should have harvested it last year, since first year woad is what you’re supposed to harvest. It blooms and goes to seed in the second year. But my back yard woad never flowered this spring, and I was curious if it was even worth harvesting such a small amount of leaves-only 50 grams worth, even though I harvested every leaf from the 4 pots. (See this post for how I process the woad.) The reason I decided to make this post, is that I put it in glass jars and photographed one of them as the woad pigment settled to the bottom of the jar. It’s just a good visual for that part of the process. In the last photo on the right above, I’m removing the yellow liquid with a turkey baster. The yellow is not a dye, it’s very fugitive and needs to get separated from the nice blue pigment.  These are the flower pots of woad that I grew in my backyard. Results? Quite good! Not much quantity, because I had so few leaves, but especially for second year woad which isn’t supposed to work, it was a very rich, intense color. It was so close in quality to my last batch, that I just added what I got from this batch to that one. (My last batch was pictured in this post.woad-over-weeds-at-least-a-momentary-victory.html)
 Woad in the bucket, after adding water soaked in wood ash, and before straining and drying into a powder It’s a constant battle to pull out the weeds in my woad bed, to give the woad some room to grow. Woad-which has the most active ingredient (indigotin) we need for both dye and pigment-is harvested from first-year plants which grow very close to the ground. The local weeds jump up quickly, leaving the woad literally in their shadow. This past week I pulled wheelbarrows full of weeds out of the woad bed, and the woad responded almost in front of my eyes, I swear the woad was visibly more abundant by the end of the week. Tired as I was yesterday, I wanted to capitalize on this temporary moment of victory-so I harvested some woad.  The weird thing was just how easy it seemed. I would compare it to making dinner; it took effort, yes, but it wasn’t like it sucked up the whole day, just one smallish part of a normal day. (If you want to see the whole process, reference this blog post.not-what-youre-supposed-to-harvest-in-october.html) I used less than 500 grams (about a pound) of fresh woad leaves. The first step is like making tea; you don’t boil the leaves, you pour the water onto the leaves and let them steep. You’re supposed to weight the leaves down, so they are surrounded by water during the steeping; I’ve used bricks inside of tupperware and all kinds of crazy things to try to do this, but last night’s innovation was I just stuck my tea kettle (with water in it for weight) on top and it was so easy! The kettle of course has a handle, so it was easy to lift the kettle and stir occasionally. O.K., not exactly earth-shattering but when you do something enough times, all these little discoveries and refinements help to streamline the process, and make it easier.  Left, sample from old batch, right, sample from yesterday's batch! The one on left started out green; even though it's losing the fugitive yellow from sun exposure, it's still much lighter, not as concentrated/has more impurities than yesterday's batch at right. I got a good yield of super-dark, rich pigment. (See right above) Once I dry the pigment into powder, I like to put each batch into its own little jar. I can compare the color of batch to batch that way, and this batch was definitely top-notch. For comparison, once I did a huge batch, and just didn’t have the patience to wash/strain out all the (non permanent) yellow from the liquid, long story short. I just dried the slurry as-was, and it was a lighter, kind of greenish blue, not the “true blue” that I just got in this smaller batch. So, I put the powder in a nice transparent glass jar and have kept it in the sunniest window in my house. The blue woad pigment is permanent, the yellow not permanent. In the 2 years that the pigment from that batch has been in my window, it has become increasingly blue! I would be wary of using that batch for a painting that I want to last indefinitely, but it was a fun experiment. Even after two years though, it’s not as good as the much more pure batch I made yesterday. Moral of the story I think, is make more small, easy to do batches.
 Left, bisque fired; right, same vase after glaze firing. In my first post on my new series of Medieval inspired ceramics, medieval-inspired.html I wrote that “So far only a few of these pieces been glaze-fired.” I think one of the strengths of this whole series is the interaction between a traditional thrown form with decorative/geometric/abstracted elements and incomplete figurative elements. An essentially one-color glaze keeps the ambiguity and imaginative leaps that the viewer can enjoy. I have come up with two strategies for making the glazes have some depth, variety and interest without getting contrived looking; local (and sometimes wonky) materials and wood kiln firing. As you can see from the vase above, glaze is not always going to hugely change the look of the piece. Even with the different background, lighting and point of view, this vase didn’t change its essential character when glazed. I formulated the glaze that I used featuring rock that I picked up off the side of route 611 in Easton. You might think that I could have used just any white glaze; but look closely at the comparison photos below. On the left, the vase was glazed with the glaze that I inherited in the ESU studio, with all commercial ingredients. On the right, another vase glazed with my rock glaze; I know it’s not a huge difference, but I prefer the rock glaze. So on the one hand, the glazing doesn’t necessarily radically alter the look of the piece from its pre-glazed state. But on the other hand, the glaze-and how it’s fired-really do matter, and give not only practical advantages like hardness and waterproofing, but improve aesthetics as well.  At left, vase glazed with all commercially produced materials, someone else's glaze recipe. At right, glaze I formulate that includes rock I picked up from the side of the road near where I live. The vases above were fired in an electric kiln; the first post I made about this series showed work that was fired in a one-day wood kiln firing. Wood kiln firings can have many serendipitous effects, between wood ash landing and melting onto the work (that was probably how glaze originated) fire hitting the work and the reduction atmosphere which causes both the clay and glaze to achieve different effects. The longer the firing, the more wood ash you are going to get, which is one of the reasons I’ve held off firing a number of my pieces; I will be taking the Anagama Wood kiln firing workshop at Peter’s Vally next month, where I can bring 30 pieces! Whether I’m using rock glazes or wood kiln firing (or both) my goal is the same; I want natural effects, not contrived painting/coloring.
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