I saw an image on Pinterest where someone had embossed the outline of a flower and filled in the spaces with water colour paints. Since I don't have a fancy embossing printer I tried to achieve the same effect with glue.
I started by taping a piece of paper over a simple image of a flower
I went over the lines with glue. The glue I used was a little thicker than PVA and had a very useful thin nozzle.
Then I waited for it to dry!
Once the glue was dry I filled in the spaces with pink water colour paint. The dried glue acted as a barrier so I could keep the clean white lines.
This was a very successful technique and I'll be thinking about which other images it would work for.