I would agree with you, that dusting-on is the easiest process. I use
potassium dichromate, as it gives you a sensitizer with less chemicals.
Ammonium dichromate is more light sensitive, which gives you shorter
exposure times and even a possibility for direct exposure from a slide or
through an enlager. Dichromates should actually be removed completely by
washing, but you might get difficulties with that part, and you have to
make your tests to find out if it changes the originally intended color.
Colors would vary greatly according to firing temperature and atmosphere. I
have never experienced any firework or explosure during the firing, but
there are chemists on the list, who might answer this question better then
me.
Are there any chemicals that might give dangerous effects in combination
with dichromates under hot temperatures ?
There is another way of thinking, which I find very interesting: make your
images in a resist material (like glue, acrylic, gelatin or gum) and use a
positiv under the exposure. Use ceramic salts (salts of metals, that give
nice colors) or water based pigments or oxides. Brush it over the whole
thing first and fire up to a bisquit temperature. You will be able to brush
off or blow off some stuff after the firing, and the image will appear on
the surface. Sometimes you do not have to do that and can simply glaze
right away, as the glaze will attach in proportion to the surface quality.
I use ready made water based silkscreen emulsions for this purpose. I mix
salts and pigments directly into it, I project directly onto it from a
negativ placed into a slide projector. It is a high contrast emulsion, so
you have to prepare a special negativ with either raster or line contrast.
But it is fun.
If you are after perfect photographic qualities, it is best to turn to
decal transfers.
As I am working on a publication on the subject, I will be glad to receive
some examples of your final work, as there are not many people doing this.
Contact me privatly, if you wish.
Good luck !
Galina Manikova
galina@online.no