Yes..you can go to a ceramic supply store and purchase underglazes....if
using underglazes...make sure you let them dry overnight on bisque.........
then you can DIP the bowls in transparent glaze a couple times at least to
get a nice coating of tramparent glaze on them. Brushing the transparent
over UNFIRED underglazed could cause them to RUN.... I always used the rule
of thumb that the glaze should be "credit card" thickness on the pottery.
Let that glaze dry thoroughly before firing too.