A short description of the stop-out and spray technique that I use to draw images onto my ceramics. It is similar to the way that I do my aquatints. See: Aquatint Class
I start with a pot that I have thrown, trimmed, and dried. It has not been bisque fired. Often I paint under glaze over the pot before I start the first paint-out. Often I do a light splattering of a color or two before the first stop-out.
Ceramics
Here is the start of a stop-out. I use wax with a bit of color in it so that I can see where I have painted. I often refer to a photograph of one of my aquatints as I paint the image. I use a small water color brush and frequently clean it in water as I am working. Still, it does gum up and will need to cleaned in very hot water occasionally.
Here is a mid-stage view of this image. I have painted and splattered a few times, each time I splattering new colors, working from lighter to darker tones. I sometimes apply more than one color between stop-outs. Also, I often vary the colors and densities of the colors over the various areas of the pot.
I splatter the under glaze onto the pot by flicking the color with a toothbrush. A good stiff brush seems best.

The pot is ready to go into the kiln for the first firing.

When it comes out, the wax has been burned off, and the pot has a kind of dust on it, which is the under glaze that was on the wax. I use a wet sponge to vigously rub away the dust off. Any spots left will remain after the glaze firing, so it is important to give it a thorough cleaning. More painting can be done with the under glaze before a clear over glaze is painted on, and the pot is glaze fired.

The pot after the final firing.

I came up with this way of working through some experiments to see if the concept of using wax as a stop-out would work. See: Spray Test

I don't know if anyone else uses this method, or a related technique. I may have come up with something new.
As I add layers of color the tones get darker in the unwaxed areas. The colors deposited onto the waxed areas do not stick to the clay when the pot is bisque fired.