There are a number of possibilities:
- Dust in the kiln falling onto the enamels while firing.
The solution, of course, is to clean the kiln thoroughly.
Are the dots really only dots, or are they bubbles? Bubbles
usually result from firing wet or moist enamels. The solution is to
make certain that wet-packed enamels are completely dry before
Specks of dust or even metal filings in the enamels.
The solution is to inspect the enamel powders before using them,
remove contaminants, if possible, and/or discard any enamels that
Are the metal stilts or tripods or trivets (firing supports)
shedding metal or rust fragments or old enamel fragments during
firing? The solution is simple. Clean the firing supports by sanding
or grinding before firing. If they are too deteriorated or cannot be
cleaned completely, discard them and use new firing supports.
Enamel colors that have become contaminated with other colors.
The solution is to inspect the enamel powders, using a magnifier
(like an Optivisor). Use a pair of tweezers to remove and discard
the offending grains of enamel, or simply discard those colors that
appear to have other colors mixed in with them.
Hope this is useful,