First you need a lathe and turning tools Andy
The rim is sanded to 600grit and then a sander sealer is applied this helps stop bleeding of the stain, blue stain is applied to this. Once every thing is dry I took an eye dropper and dropped spots of water of different sizes and in a random pattern.
I used car automotive paint in the rattle cans one white and the other black.
Starting with the white and at a very low angle just slightly above horizontal I sprayed a very fine mist over the whole rim, changing to the black and rotating the bowl 180deg and repeat the same process as the white.
DO NOT tilt the bowl at any stage and also don't get too close when spraying the black and white paint otherwise the bubbles will move.
This now need to be left until the water has dried fully and another DO NOT touch anything as you still can smear the paint even though it is dry. Give it two or three light coats of varnish again from a spray can I found Acrylic gloss spray was great, this has now sealed every thing in.
Return the blank to clean up the outer edge from any over spray and turn the inner bowl.
Does that help Andy