For "Where There's Smoke" I used a clay on glass technique, where the images of fire where "sculpted" into the clay, down to the glass, revealing the light below. I used black modeling clay, which was completely opaque. This was back lit by a photo flood light. There was a sheet of diffusion filter about six inches below the clay on glass layer. It made the light very bright but glowing more than glaring. Then I placed a sheet of glass painted with fire colors over the clay. I used Pebeo Vitrea 160 paint, it's a glossy transparent paint for glass. It's a kind of enamel paint and smells like nail polish, only ten times stronger. I let a heavy coat of red set up a little and then painted into it with a stiff brush. It made flame like striations in the old paint while filling in the lines with yellow and orange. This sheet of glass was positioned in a random way over each sequential frame "drawing". The glass layer was not flush with the clay. As the clay layer was uneven and changed from frame to frame, the flame glass was always a little higher then the clay. This gave the animated flames a lot of extra glow, and because it changed every frame, it also gave it a nice flicker.
These images show the clay on the glass with the back light on. The second image shows the painted glass layer, and the third image shows the combined elements.
It's like drawing with fire.
