Fired to cone 6. These are not glazed. Polar Ice is very vitreous and very white, an ideal host for stains. However there is a caution: It has a high firing shrinkage. If a stain is refractory it can reduce that shrinkage considerably. On the other hand, some stains will flux it and drive the shrinkage even higher. That means if that if high and low shrinkage stained versions of Polar Ice are laminated the firing will create a tension-time-bomb that either exits the kiln cracked or cracks down the road. This work is courtesy of Robert Barritz.
Ceramic stains are manufactured powders. They are used as an alternative to employing metal oxide powders and have many advantages.