We unloaded two lovely vases from the kiln today. They had been glazed in a mixture of overlapping colours and fired in a reduction atmosphere. This resulted in lots of reds on the surface.
The downside was that a lot of the other pots that were next to them also turned red, when they should have been green. They were ammonite mugs destined for a customer in Devon who had ordered 200. Now he can only have 150!