a black contour marker for glass and porcelain. The tip is mm thick and the color is very opaque. Let your decorated porcelain dry for 4 hours and then be cured in the kitchen oven at for 90 minutes, to be dishwasher safe.
Weekend DIY Project: Decorate a Mug or Cup -- Bake the mug in the oven for 30 minutes at 350 degrees. Let it cool completely before using or washing it. When you wash the mug, hand-wash it gently instead of throwing it in the dishwasher.