In the March 15 entry, I wrote about various methods of reserving the white of watercolor paper. One of those methods is the use of frisket, or masking fluid.
The tiny white blossoms at the corner of the fence in this detail from “Arbor Gate” (#090702) were reserved using liquid frisket.
If you want to try using frisket yourself, start with a throw-away brush and wet it thoroughly before dipping it into the frisket fluid, which will dry quickly and tend to glue the bristles together. Redip the brush in water (or better yet, a solution of dish detergent and water) between dips into the frisket—no more than 20 seconds apart—to keep the bristles from sticking together. Wash the brush thoroughly as soon as you are finished if you ever want to be able to use it again.
The frisket itself may or may not be tinted. It’s easier to see its location on the paper if it has a tint, but even if it is not tinted, you will be able to identify areas of dried frisket on your paper because of the slight sheen those areas will have.
Especially if the frisket fluid is tinted and you see a layer of color lying at the bottom of the bottle, you may feel tempted to shake the bottle to mix it up. Don’t do it! Shaking the frisket bottle will incorporate air into it, which will introduce bubbles into the “juice” your wet brush picks up. If you spread bubbles onto your paper, the frisket will not go onto the paper smoothly, and the bubbles may pop as the frisket dries, leaving you with uncovered spots in the area you were trying to mask.
As soon as you are finished using the frisket, replace the lid tightly to inhibit evaporation. You may have to periodically remove long, rubbery strands and globs from both the mouth of the bottle and the bottle cap to be sure they don’t interfere with a secure seal.
Allow the applied frisket to dry completely before painting over it. When all your paint layers have been applied and the surrounding paint is thoroughly dry—no longer cool when you touch it with the back of your hand—use a “pickup” or white eraser to lightly roll or pluck the frisket off the paper. (I recommend testing the dryness of the paper only with the back of your hand because your palms and fingertips are more inclined to leave oily deposits on the paper. Your natural body oils will interfere with any subsequent paint you may wish to lay down onto the surface of the paper.)