If you want to mask thin lines or really small details, the dip pen is an excellent tool.
Blue shadows (an exercise with masking fluid) - Erik Lundgren
Visual Art Source
Grizzly's Big Movie, Idea Wiki
73259119-12303087-Mission_Tom_Cruise_s_latest_action_film_seems_to_be_having_troub-a-16_1689464098062.jpg
73259101-12303087-Budget_Globally_the_action_flick_has_pulled_in_82_1_million_acro-a-18_1689464098115.jpg
the sun. The Smithsonian built the
Charlotte sun herald
th?q=Unveiling the Wonders of New Zealand
Visual Art Source
Blue shadows (an exercise with masking fluid) - Erik Lundgren
Scrape out white - Erik Lundgren Watercolor
the sun. The Smithsonian built the
Masking fluid with dip pen - Erik Lundgren Watercolor
Who Framed Roger Rabbit 2, Idea Wiki
Visual Art Source