Many months ago, I came across an art medium used by painters. I cannot remember the exact term for this medium. It is white, but is transparent once used, I believe... having the consistency and appearance very similar to white liquid Elmer's Glue.

In essence (referring to this medium as Medium A), a painter would first sketch their desired image in pencil onto paper... be it typography or any image, really. Any spaces they wanted to remain white in the finished work (like lettering or small details, for example), they would paint and fill in with Medium A. Once medium A has dried, they would paint all over the paper (including over Medium-A-covered areas) with watercolor, typically with multiple colors. After the painting has dried, the artist would peel off Medium A areas from the painting, being careful not to rip up the paper fibers themselves along with Medium A. In essence, it has a resistance effect similar to a white wax crayon drawn underneath watercoloring.

An example of what the result after using Medium A could look like:

enter image description here

What is Medium A really referred to as?

  • You call negative paint waaaaaah-tercolor!
    – user24
    Commented Aug 5, 2016 at 12:10

1 Answer 1


I think what you are looking for is called a masking fluid. It is sometimes also called liquid frisket.

Masking fluid can be treated like paint which wherever it is applied will protect what is underneath. A feature of most masking fluids is that they are removable once dry.

Some masking fluids are strongly hydrophobic (water repellent), and water will bead on its surface. This can make it tricky to tell when the whole canvas is dry. Trying to remove the masking fluid but having some undried paint pooling on the surface can cause heartbreaking smears.

Some masking liquids change colour after they dry. This makes it easier to see where you have applied it, and easier to tell if you have removed it all after the work is complete.

Masking fluid is great for creating negative visual effects, like you describe.

Winsor & Newton Masking Fluid

  • A tip for using masking fluid. First, wet your brush with water. Then apply a thin coating of pink art soap to the hairs of the brush. Then use the brush to paint the masking fluid onto your paper. The little bit of soap on the brush hairs helps to keep the masking fluid from sticking to the hairs, making it easier to wash your brush after applying the masking fluid. Masking fluid is rather like rubber cement and has a tendency to stick to the brush hair and can be a major pain to remove once it starts to stick. The little bit of soap helps to prevent it from sticking to the brush hairs.
    – Matt
    Commented Sep 22, 2017 at 0:54

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