This pair of jumping dolphins was painted on a piece of cardstock which I had "primed" with two coats of white acrylic paint. I used the paint because I don't have gesso in my flat. It worked to some extent and stopped the cardstock from sucking in too much paint. However I didn't apply smoothly enough and thereby the texture was a bit too rough.
The other thing which went quite well was mixing a nice strong red colour out of the magenta acrylic ink and the yellow acrylic paint. And it was fun playing with paints and experimenting - even if the result was not perfect. It is a way to learn and to practice!