Spots on china, stippling white

[chuka_lis]

Stippling White China Paint is a product that works well for highlights.  Matte paints do not create this naturally.
Stippling White are mixed in the same manner as china paint, but are more opaque when fired. Mix your product well, keeping it stiff enough to hold a peak when you pull up the palette knife from the paint.  If you want it to be a little stiffer add a little tin
oxide to it....not much no more than 10%.
You can use a small stylus tool, or a large sewing needle for applying it on spots.  Scoop up a small amount of paint and apply to the place.  Be aware about the correct amount and position for the highlights. You can use stippling white like you do base for gold or enamel too.  You just have to test it to make certain you like the results.  Of course, you can stipple it

Sometimes black spots showing up on  bone china pieces after firing.
Some people suggest that sanding the unglazed edges really well will open up the porcelain and let any trapped moisture out and prevent the spots.
Actually, the black spots in bone china are a result of underfiring in the manufacturing process.  Sometimes spots will also occur if grease has gotten under the glaze.
A second fire can bring out even more spots. 
An old China Decorator suggestion was to boil the item in baking soda and water, although a positive outcome was not guaranteed.  Firing bone china at high temps (cone 8 or so) will cause the glaze to bubble and remain bumpy but is unlikely to remove the black spots under the glaze. 
When in doubt about bone china, a good practice is to fire it before a first fire with paint.  If it has spots, I discard and move on.