Working With Masking Fluid

Masking fluid on watercolor paper
Masking fluid is a wonderful tool to have in your studio. It is commonly used to preserve white areas of paper when painting with watercolors.  I have used it to create interesting effects with acrylics as well.

When using this product remember that it is best to stir rather than shake the bottle. Liquid mask is a water-based suspension of latex with ammonia added as a preservative. Shaking breaks the suspension and causes the latex to clump.

When working with masking fluid it is imperative that you first dress your brush with soap. I use a small segment of bar soap. Wet your brush and stroke it across the soap to create lather. Do not rinse. Use the soapy brush to apply the liquid mask.

Apply generously to your design areas that you wish to keep white. When covering shapes I usually start with the perimeter then fill in the rest of the element.  This type of application is demonstrated above right, with my masking of floral elements in order to paint the surrounding area.  The image shows before and after the mask is removed.

Liquid Mask
For lettering simply "paint" the letters with mask the same way you would using paint.  An example of this type of application is the greeting card, at left, on which I masked the word "smile".

Rinse and re-dress the brush periodically. After this has dried check to make sure there are no gaps in the liquid mask. If you find any area to be questionable, touch it up with a second layer of liquid mask.

Allow the mask to air dry before painting.

After using liquid mask, change your rinse water. Residual mask particles float on the surface and will cling to your clean brush.

When you have completed your painting, or the segment being preserved, make sure that it is absolutely dry.  Then remove the mask.  For small areas you can roll it up with your fingers (like rubber cement).  To remove larger areas, using a rubber cement pick up is preferred.