Art Spectrum Masking Fluid
Art Spectrum® Masking Fluid is a pigmented rubber latex-based liquid used for masking out areas. The coloured tint allows the artist to see the areas where it has been applied.
Can be applied with a silicone brushes or a regular brush. But beware using your nice watercolour brushes as the Masking Fluid dries quickly & can easliy wreck brushes. Don't leave the masking fluid on paper for more than a few hours. Once paper is totally dry it can be removed with a crepe eraser or gently with a clean finger.