I painted this bisqued porcelain bowl last week with orange and brown underglaze, then put a black underglaze on the inside.
And this is how it turned out when fired. The reason the colors are so intense is that I low fired instead of high fired it.
The downside to that is that the clay never vitrifies in a low fire, therefore is still very fragile and not really food or water safe.
But it's pretty when it's done, huh?