Decided to try a little experiment with gouache and waterproof ink.
Firstly, drew the outline of the flower with pencil and then laid white gouache in places.
Then when the gouache was dry I painted over the whole thing with black waterproof ink.
Wait until the ink is completely dry. Then wash off under cold water using a brush to gently remove some of the ink. In theory, where the ink lays over gouache it should lift off revealing the white paper underneath and the ink where there was no gouache remains untouched.
The finish was not quite as expected - in fact, you could say it all went hideously wrong. lol
However, it is quite an interesting effect and I will try this experiment again. I quite like the effect, it's just the black lines across where it didn't quite work for me.
I think perhaps I need to lay the gouache a little thicker, allowing it to dry completely and then go over with the ink. I also think it might be better to try something a little more robust than 140 lb paper. This could be the reason the ink sunk into ridges or lines across the paper.