In Portugal we use the majolica technique for painting on bisque tiles. It
is the same technique that has been used for 4 or 5 hundred years. The
bisque tiles are given a coating of white or off white opaque glaze and
before being glaze fired are painted with pigments mixed with the base
glaze. The designs are first worked out on paper and then copied onto
tracing paper. The outlines of the designs are pinpricked to make a stencil.
Use a charcoal filled cloth (I can't remember the name) to dash over the
stencil leaving a charcoal outline, which will burn out in the glaze firing.
It is often difficult to convince the children that the black outline will
burn off. Blow on the tile before painting to remove excess charcoal.
You will have to experiment to see the colours that you can obtain with your
pigments. Painting on glaze is quite different than other techniques as the
"paint" dries almost on contact. Paint, stipple or sponge - experiment to
get the results you want. These are permanently painted tiles after firing
and used outdoors or indoors. If you need more information please ask.