A ruling pen is the best way I have found to apply masking fluid in thin lines in a watercolor painting.
CHAPTERS
00:00 A ruling pen for watercolor paint and masking fluid
00:33 Using watercolor paint in the ruling pen
00:53 Painting grass and tree branches with watercolor and a ruling pen
1:48 Straight lines using a ruler as a guide
2:46 Using a ruling pen to apply masking fluid
4:57 Grass and tree branches in masking fluid
5:24 Simple clean-up
6:04 Removing masking fluid
A ruling pen is a drafting tool. I got mine in a small drafting set and have really enjoyed using it to apply masking fluid when I need thin lines or detailed marks. Clean-up is also a breeze!
The masking fluid I'm using is called Tear Mender.
