I did this batch-to-formula glaze chemistry calculation to help a potter with a transparent cone 10 glaze for a Plainsman P500 (a 25x4 porcelain). This version of Desktop Insight ran on the TRS-80 Model I and III, they were the first popular consumer microcomputers for business (outselling Apple 5-to-1). Notice the report uses capital letters; the machines did not support lower case! The dot matrix printers of the time lasted forever on an ink ribbon. Fanfold paper fed from a box, I could tear off only as much as was needed for a report. Boot time was less than 5 seconds. Here is what is amazing: In 2021 I found this same recipe in my Insight-live account (the green screenshot)! The results are a little different; I had the chemistry of talc wrong in 1980. Through the years, I wrote code to migrate from one system to another, and eventually it got to Digitalfire.

This is a cone 6 oxidation test mug I made in 1981. The speckling in the glaze was made by adding iron stone concretion particles. But this also has a story. Most potters at the time were firing cone 10R or low-temperature, cone 6 electric stoneware was a new development. Note the incised code number: "81-R-5". Digitalfire data archival was already well underway on my TRS-80 computers. The base also has a "60#" marking. I was trying a finer 60 mesh particle size to alleviate the glaze pinholing problems that plagued Plainsman customers at the time (their products were made at 42 mesh and kilns did not have controllers that enabled drop-and-hold or even hold-at-temperature firings that are used now). Pinholing was one of the first glaze problems that I studied; many glaze chemistry projects, using my new Desktop Insight, were aimed at making glazes having melts of lower surface tension and higher melt fluidity (using frits).

The clay here is called jiani, it’s found in various layers along with other yixing clay (but not used for teapots). The translation of this video screen capture (below), provides a fascinating insight into how they judge the suitable temperature at which to fire. First, technicians measure the porosity and firing shrinkage over a range of temperatures, likely looking for a firing "sweet spot". Notice shrinkage reaches a maximum at 1100C, then drops off as the clay begins to expand. But this is not the only thing considered. Notice, in the comments, that they are also looking for "surface luster" (which is not found). They also comment about a "dull sound" and "crisp/clear sound" (so they must create a sounding vessel of some sort). They also break a fired piece and comment of the nature of the cross section, revealing something else interesting: The clay holds on to a dense cross section for 100C degrees after reaching maximum fired shrinkage.

The Yixing teapot craftsmen appear to break all the rules and yet produce impossibly delicate and symmetrical pieces. Hao-Tong Yan, one of those craftsmen, and I have been trying to understand the technical reasons for how this amazing craft is possible. It turns out not to be magic, but actually a highly evolved understanding of a very unusual material. Here are some of the things that we are coming to understand (which is making it possible to create a facsimile of the clay in North America).

-The clay is not highly plastic; the workability comes from surprising places.
-The clay has impossibly low water content, yet can be formed.
-Craftsmen flatten the clay with a mallet, instead of rolling it, yet it does not stick to the board.
-Sections are simply glued with slip, yet they hold.
-The clay burnishes, yet is not smooth.
-Fired ware is smooth, yet the soft clay appears sandy.
-The fired surface is glossy, yet there is no glaze.
-The fired clay appears super dense yet does have porosity.
-The Yixing ore can have the appearance of being like rocks, yet they make a workable clay body from it.

Thanks again to Dominic Legault, who set this up and stopped it. This is my first exposure to a fundraiser; it is amazing what is possible. I was obviously excited about how it could accelerate my succession plan, but realized that Digitalfire has to remain completely a volunteer labour of love. I was worried about Dominic's reaction to cancelling this, but he is on board. The refund process began on June 27.

Please don’t believe twisted interpretations of the events during the latter part of June. You have seen me share freely for well over 4 decades. Please rely on my record rather than misinformed recent postings. I don’t rebut or flame people on social. But it does hurt when they say things that are totally against my character. As soon as I learned a GoFundMe had been started, I posted the succession plan. But it was behind a disclosure triangle and people were not opening it (see above). I have been working on item 1 for a year already; hopefully, 6 more months will do it. It shocks me how big and complex Digitalfire has become!

I posted this on June 19.

I need goodwill with Plainsman. I know you have been passionate about this whole affair in the past few days. I underestimated how much. Some were so passionate that they have caused trauma with Plainsman staff, we must undo that. Having goodwill with the company I partnered with to make Digitalfire is so important and will make me so happy. We both "pulled the dragon's tail" over misunderstandings.

I consulted Plainsman before posting this, and they requested I add: Here is the biggest one: Digital Fire is not at risk and never was from Plainsman.

I need goodwill, especially if you put staff under stress, and you can help me get it. My first idea was to fill their office with hundreds of bouquets of flowers, but now I realize that's too much environmental impact. I'll credit you 4 years of Insight-live if you already did (this statement was added after I realized this was not a wise request).

Thank you to the hundreds of messages I am getting every day for support. Yikes. I can assure everyone I am not retiring; I am just getting started. I cannot believe the offers of help I am getting from coder/potters, lawyers, negotiators, designers, etc; there are so many of them. And how many countries. This is amazing. Messages from countries where potters and industry rely on Digitalfire because ceramic fabrication information is either kept highly secretive, despite a large manufacturing sector, or simply doesn't exist, really moved me. And an offer from a Google engineer to help. Or even a suggestion to move the dark web! Information on how to change licensing to clarify reuse. Advice from human rights experts on the importance of freedom of information. How to organize team coding. How to automate translation. Many offered physical server resources and hosting. Others offered new tools they have developed to integrate into Digitalfire. And so much more.

The old logo is from the late 1980s and was used to promote Desktop Insight at trade shows and to advertise it in magazines and later on the early internet. It was done in Aldus Freehand, an early competitor to Adobe Illustrator. Vector graphic illustration was revolutionary at the time. Amazingly, many artists even today do not know what vector graphics is, they are still working with "pixel pusher" apps like Photoshop.

I asked Gemini how it made this, and it said: "I started with a blank canvas of random digital noise (a chaotic grid of pixels) and gradually refined that noise over multiple steps based on your prompt and the layout of your original image. There was not need for a vector stage; the smooth transitions, glowing embers, and soft gradients are baked right into the generation process from the very beginning."

Glazing black clay bodies stained with manganese is just about impossible with typical transparent glazes. The glaze over-fluxes the clay surface and ruins the color. Worse, if it accelerates surface maturity, the body can blister or generate LOI gases that blister the glaze. How about transparent glazes over a black engobe instead? At least the body color is not lost. But the wrong transparent glaze can do what you see here (inside left).

These mugs are a buff stoneware, Plainsman M340. A black engobe was applied by pouring the inside and dipping the outside two-thirds of the way down.

Left: A L3954F black engobe was applied inside and upper exterior at leather hard. After firing to cone 6 using the PLC6DS schedule, G2926B—which is crystal clear on M340 itself—became completely clouded over the engobe because bubbles generated during firing remained trapped in the melt.

Right: The entire mug was dipped in GA6-B. The Alberta Slip particles and the melt characteristics of GA6-B promote bubble coalescence and escape, producing an exceptionally glossy jet-black surface over the same engobe.

When you learn to make and use engobes correctly, they make magic possible. Here I am turning a dark rustic body into a smooth white one (rear mugs) and a white body into a dark one (front). The engobes have been applied at the leather-hard stage. That is the perfect time, the engobe and body are clay bodies, designed to fit each other; they dry together and fire together creating an inseparable bond.

Handles have been applied, and they have dried to stiff leather hard. Engobe was poured in, poured out, then the mugs were pressed, lip down, into it and extracted. No dwell time was needed. This dipping engobe is DIY thixotropic (not available commercially anywhere). That means I tuned it just before use, to just the right degree of gel (enough for it to drain to the right thickness, then gel just as the last few drops fall from the rim). Honestly, these are a beauty to behold at this stage, the silky, drip-free surface is just so perfect.