While I use brushes for much of my glazing decoration, the kiln does just as much painting as me. Unlike painters, potters have to give up some control of their artwork by using fire to finish the surface. I brushed iron stain onto the rim of the mugs below, then the iron dripped down the walls during the firing.
Each pot is first dipped in a bucket of glaze. I chose glazes that move and drip during the firing. The image below shows how I brush colorants like iron or cobalt onto the surface. This adds color contrast, and encourages drips and movement.
After glazing, my pottery is loaded into a natural gas kiln. This is basically a huge oven with no windows that heats to about 2400 degrees F. for about 12 hours. After 2 days of cooling, I open the kiln with fingers crossed, hoping that the “kiln gods” gave some good colors to the pots.
The images below show how I use iron, cobalt and copper stains to add color and movement. I brushed them on as a vertical line, then the stains melt down the pot during the firing. This big pot barely fit in the kiln- we had to take out a few of the floor bricks!
The Copper Red glaze is very responsive to the flame path in natural gas kilns. The gaseous atmosphere produces red colors, while the clear/green colors show up where the pot was more oxygenated. The flame naturally paints the glazed surface.