Pots series 13 - A brush of oxide

For this series of small pots, I used a simple design: white background, brushed with pure oxides. I used cobalt for a solid blue and black iron for a rusty effect. I used a wide, synthetic rigid brush and applied a tiny amount of oxide on. For comparaison, I previously brushed a shiny black glaze on the same white glaze;  the colour is much more intense and deep using the pure oxide.
I also tried out an underglaze pencil (followed by a coat of transparent glaze).

Front, left: black iron / Back, left: cobalt / right: shiny black glaze

Underglaze black pencil