https://youtu.be/aMfR5m0eAuA
I use a combination of mediums when creating these paintings, the main one being acrylic ink, which used in this way is similar to working with watercolour. The advantage for me is that once the ink is dry you can work over it and it will not blend with the colour below, for example when painting these leaves I can put the lighter colour under and the darker on top.