Interesting Bisc

The second bisc of two; the first was rather overfired,so I tried to shut the second one off sooner,got involved [inevitably] in some fascinating discussion with a visitor as the critical time,and missed it by a bit. I think my ideal bisc is around 920 - when my blue slip turns from its unfired pink to blue,that's the upper limit - soon afterwards it starts to get too hard to glaze [top picture]. So in this kiln,you can see clearly that change in colour - sometimes on one pot [middle picture] - and the general flow of heat in the kiln [bottom]. I think that this was overfired by 10-20 degrees,and I'll try not to do it again. now I have to turn off the second glaze kiln - a bit hot on the botttom for a change.