Bubbles in glaze

and what is this glaze called with bubbles?

Impure?
It happens. I don't think it has a name, and I've had new pieces from potters where I've assumed it was a gaze fault but apparently it's not - or at least it's accepted as just one of those things. Maybe it's impurities in the glaze or degassing from the clay body or underfiring?

Ahh I assumed it was experimental or intentional but you think it may be underfire or something. Interesting.

The lovely ragged bowl I have by Matthew Blakely has bubbles in the blue glaze. Maybe it's a trade off between firing to get the right colour vs firing to get a clear glaze?

Cross section of Ming Dynasty celadon glaze, which is typically full of bubbles, with white porcelain in the middle. So a function of the glaze rather than an error

Celadon glaze drips on a piece by Eddie Curtis, Potfest 

Well they do pool but if you look at third photo of mine it's essentially all over bubbles. Possibly more where glaze is thicker? The odd thing is you don't really notice it until you look closely.

On another note I bought a John Bew (Odney Pottery) piece and it did something very unusual also. He had underglaze it with blues then clear glaze on top but mixed more pigment in a layer on top. When the light hits it right it glows! Essential backlighting the top glaze. Only happens when the sun is on it. It comes to life. I think Ray Finch did this and I saw a piece on eb but did not win it, bastard other bidders!

https://www.20thcenturyforum.com/t15379-john-bew-frank-spindler-odney-pottery-cookham-berks?highlight=odney

This is a candlestick that Dylan Bowen refired because of bubbles in the glaze (I saw some single fired ones too, with the bubbles), and they're turned into a bluish opal like effect on the surface

I did not know they could refire pieces. I suppose they need to get the temperature right

Doug Fitch once said that half the pots coming out of his wood fired kiln may need to be refired because they were sitting in parts of the kiln which were too cool. But the alternative is having half the pots over cooked, which then can’t be refired

Detail on Matthew Blakely’s ragged celadon bowl

Yes that's exactly the same. Is that one celadon?

I think so, although I don’t know the difference between celadon and ash glaze

To me the bubbles WITHIN a glaze, looks fine, adds interest. BUBBLES that break on the glaze (like mine) are sharp and it mens I have overfired.