This is a topic that I hope will inspire some collector participation, as in, send your photos. There will be a follow-up post.
We all know that these ceramic artworks are fired in kilns to achieve their permanence and luster. What some don't know is that despite careful monitoring and loads (literally) of experience, temperatures can fluctuate inside the kiln. Sometimes, it's a matter of the arrangement of the kiln load, or how close an individual piece is to a heat source (be it gas jets or electrical elements). At other, more infuriating times, it is due to a spontaneous malfunction of a regulator, relay, or other modifying mechanism. Those are the times that try potters' souls, but not nearly as mind-melting as when you are a factory with a load of dozens or hundreds of pieces. Some of these "Toasties" can be salvaged and sold; some, well, they sort of melt where they stand.
Not all factories are horrified by the resulting glaze variants. Some, like the first studio where I served an apprenticeship, absolutely delight in variants. It gave that pottery's stoneware tiles a color family range, exactly as the original Batchelder tiles. I remember Laird being a big fan of his glazes' extremes, particularly when they got a little toasted by the jets.
Another pottery, Hagen-Renaker, kiln fires large numbers (compared to us hobby ceramists) in each load. Over the years, I have seen a few HR factory "Toasties". These appear different from the blackened miniatures resulting from accidental reduction firings (without oxygen). Toasties retain some of their intended hue, but usually only in their deepest detail. I don't want to wax overly technical here, but things are happening underneath the glaze on a chemical level, beyond the human hand's application of that pigment. Please forgive the label, "Toasty"; it's all I have to work with until I learn a more friendly term. "Over-fired" is just not a cute word.
When were these made? They have happened occasionally, over the decades, and still happen. I bought these two HR reissue Native Dancer models in June of 2009. They were in a regular, brick-and-mortar gift shop HR retailer, from the same fresh shipment.
This is the normal one.
Here you can see how the Toasty's pigment is reduced and grainy over the broad surfaces, and only the details cling to color. These areas only have blotchy rich color. It's almost the look of hand-brushed watercolors, not airbrushed underglazes! This effect is universal on Toasty glazes. The airbrushed pigments are, in fact, dissipated chemically, without the influence of the human hand. In my own ceramics experience, I've seen this happen when pieces are glaze fired repeatedly (or accidentally overcooked).
In a HR firing moment between 1981-1984, probably early on in that period, judging by her fully tri-eyes, a regular palomino large Zilla got toasted. Zilla photos courtesy of collector Karen Beeson.
She was over-heated so much that her seamlines, greenware sponge wipes, and white mineral specks rose up under her glaze (see her back).
I get that it "looks" like color was swiped on top, but it's actually the pigment settled into her clay surface texture and minerals (grog) of the clay changing the surface, as it attained a higher temperature. At HR, sponging the seams down is standard practice. This removes the outer "silt" layer of fine clay and exposes the micro texture of the clay (fine grog). Those white specks are the grog exposed after greenware sponging, usually unnoticed under normal firing conditions.
The body shading is on all SM palominos, it just is palomino color when fired correctly. Some underglazes are unstable when heated above the ^04 range. Weird things happen to over-cooked dirt.
Note that her belly, where no sprayed underglaze was applied, looks fairly normal.
Everybody wants to know if these are more valuable, since they are factory OF variants. Honestly, some people are grossed out by them. Do not expect a Toasty to win a Breed class at a model horse show. They don't look like real horse colors. There is no way of telling if they are even all that rare, and this is not a condition that is only found on one color, nor one mold. The circumstance is random and an equal opportunity underglaze obliterator. Fresh Toasties retail right alongside normal siblings, so it is not like the factory retains them, out of collector hands. They are out there.
On a more personal note, I was present for the following over-firing, back in 1996. The Manual Kiln Sitter had a bar failure, and roasted a whole batch of Joanie's early Pour Horse Pottery Owynn. Talk about scorched earth! These earthenware fellows were vitrified, and drooped upon their stilts like Vlad's victims. They couldn't be glazed, so technically they are bisque Toasties. They don't have the pigment dissipation effect only seen in glazed Toasties. Instead, the overdone Owynns show the instability of gray and black underglazes at excessive temperatures. Here is one of the lucky ones, and even he stands 1/2" shorter than a normal gray Owynn. Yes, the gray one is what he was supposed to look like, had he survived past this fatal bisque firing. If this had been a glaze firing, I don't even want to think about the collateral damage that would have done to the kiln's furniture. Meltdown.
Toasties happen, and they can't be 100% prevented. They aren't realistic nor gem-like, and their collectibility is subjective. People like them or hate them. One thing is certain: no one orders their horses "extra crispy".