Last weekend I had a chance to participate in my first raku firing where we use the reduction process. It was the kind of event where it feels like a party, you get to play with fire and ideally get something cool out of the deal. It was sunny, plenty of coffee was consumed and we enjoyed pizza for lunch. And possibly some cold beverages were involved.

(this vase is NOT mine but was one of the better pictures...will post mine if I remember to take photos in daylight).

The temperature of the kiln when pieces come out is about 1800 F which requires good nerves and steady hands. The items are in the kiln until the glaze is molten, then when they are taken out we place them in the garbage cans that are lined with newspaper (in this case). The paper ignites almost immediately and the flames draw the oxides out of the glazes, causing what's called a reduction. The lid is closed before the fire burns down so that the pieces don't have a chance to re-oxidize. They are opened about 20 minutes later when they are significantly cooler. The water spraying cools them rapidly down to air temperature so once again, they don't have a chance to re-oxidize (which would change the colours significantly). At least that's the way I understand the process so far. Feel free to research...