What is Masking Fluid?

Masking fluid is essentially liquid latex that is applied to watercolor paper to preserve areas from the paint. It dries into a waterproof film.

How do you apply it?

It can be applied using many tools such as a brush, toothpick, cotton swab, toothbrush, or a ruling pen. There are even fine needle nib bottles you can purchase for getting fine lines.

What does it look like?

Masking fluid is sold in different forms as well. You can buy bottles of the liquid mask as well as markers for making fine lines and detailed work.

How do you use it?

The first thing you want to do is plan your painting carefully. Most of the time masking fluid is applied to the paper before you use any paint at all in order to preserve the white of the paper.  Think of the application of the mask as white paint because it will be white once you take off the mask at the end of your painting.

Once you have your drawing in place and you have the painting planned out then you can apply the masking fluid with any of the tools I mentioned previously.

If you are using a brush I would suggest using an old brush you don't care about and to further the longevity of this brush as a "masking fluid brush" you should thoroughly saturate the brush first in soapy water, remove excess soap with a piece of paper towel then dip your brush in the masking fluid. This helps to protect the bristles from the mask. Immediately wash your brush after use with soapy water.

Handle the bottle of masking fluid carefully. Never shake your bottle of masking fluid this will result in stringy clumps of latex. Also, the air bubbles in the masking fluid will be transferred to the paper and those tiny bubbles will produce an uneven mask.

Make sure your paper is completely dry before applying the masking fluid or else the liquid latex will get stuck deep in the paper fibers and you will not be able to remove it without ripping the paper. Ask me how I know this. LOL

Also do not use a hairdryer or heat tool to hasten drying time!! This will also cause the latex to embed in your paper and will not be easily removed. Watch out for sunlight! This may also cause the fusion of latex and paper to be a permanent thing.

Wait until your masking fluid is completely dry before painting on your paper. Depending on how much and how thick your application is I would give it a good 20 minutes of drying time.  After you have finished your painting and your watercolor paper is completely dry you can then remove the masking fluid.

I like to use a masking fluid pickup to erase the latex. Using your fingers can leave oils and smudges on your work. You also don't want to leave the masking fluid on longer than you have to because it is more likely to embed in the paper fibers with time and will be harder to remove. Some masking fluid is tinted so we can see our application better but this tint in the liquid latex can also have a staining effect on your paper over time.  So once your paper is dry remove your masking fluid :)

Lastly, if your masking fluid is becoming too thick over time, you can add a bit of water to thin it out and this makes for easier application.

What are your thoughts on masking fluid? Do you use it in your paintings?