Airbrushing Transparent Watercolor–Block, Tube and Liquefied
Watercolor was the first type of paint to be used in the airbrush, and why not? Watercolor has all the necessary attributes–thinning with water to an appropriate consistency is easy; the tip of the airbrush isn’t as readily clogged as with other paints; cleanup is quick and easy with soap and water; and after applied, it can be manipulated with various traditional watercolor techniques.
The three types of transparent watercolor are block, tube, and liquefied. Gouache, an opaque watercolor paint, will be discussed at another time.
Block watercolor is available in various sized hard, compressed blocks of pigment that is lathered with water into a liquid paint with a paintbrush. That paint is then transferred with a paintbrush from the watercolor block to the airbrush paint reservoir. This method is best used when only small amounts of paint are required, since to do otherwise would be highly impractical. The type of airbrush used, therefore, is one with a small paint reservoir such as a slotted gravity feed or the traditional side feed with a small color cup.
Tube watercolor is the most commonly used in watercolor technique, including with the airbrush. With many manufacturers and an unbelievable array of colors available, airbrushers prefer tube colors because you can mix a small amount of paint by squirting it into a small paper cup and adding water to meet the desired consistency. Then it is just poured into the airbrush paint reservoir. Because each color is mixed in a small, confined area, there is much less possibility of contaminating one color with another, which is easily done with a pan of block colors. Also, if the watercolor dries in the cup, it can be reconstituted with water.
Liquefied watercolor is pre-reduced to a consistency that is readily sprayable. Although water-soluble, those colors manufactured today are–in most cases–more like a dye, rather than a pigmented watercolor. These transparent watercolors are a preferred medium by illustrators because they are quick and convenient to use; and the colors are extremely radiant, although they may not be manufactured to the highest degree of permanence. Also, they may not be manipulated in lifting techniques or work well in a wet-in-wet situation.
Watercolors can be airbrushed onto numerous surfaces. Most absorbent paper surfaces–in addition to illustration boards, acetate, and photographs–are suitable. Since, when properly used, the airbrush does not overly wet the surface, there is little chance that the paper will buckle. However, it is recommended that you work on at least 2-ply paper; and if you are strictly airbrushing, the paper should not require stretching beforehand.
Masking techniques are very handy for the watercolorist using the airbrush, and there are different materials that can be used to make frisket/stencils, depending on the work surface. Frisket film, which is a self-adhesive transparent stenciling material, is generally cut directly on the surface. Therefore, you must use care not to cut through the frisket and into the paper. (Practice is highly recommended.) You must also insure that the adhesive quality of frisket and any other self-adhesive stencil material is compatible with the paper surface. It’s best to test it on a corner before putting a full sheet down on the artwork.
Tape is also a handy stencil material. On paper surfaces, drafting tape is recommended because of its low-tack adhesive. Specialty tapes such as pin-striping tape or crepe paper tape (for doing curves) also come in handy.
Liquid frisket is used identically in airbrush technique as in traditional watercolor technique, i.e., to block out white areas of paper for highlights. This material, similar to rubber cement, is painted on with a paintbrush or applicator (and is notorious for ruining paint brushes). Once dry, which is quickly, it is painted over. After the paint has dried, the liquid frisket is removed by rubbing with a finger to uncover the intense white of the paper underneath. Do not use liquid frisket over an area already painted in watercolor, as it will remove the underlying paint as well.
Handheld stencils and templates, found objects, paper doilies, etc., can also be used in airbrushing your artwork.
Once the watercolor is complete, airbrushing a fixative or an acrylic varnish over top will provide protection. Because the surface is not touched by the airbrush as it is with a paintbrush, you need not be concerned with damaging the painting underneath.
The watercolorist has several different types of paintbrushes/tools in his studio for various applications, and the airbrush also has its place among them. Use a mop brush to do a wash and an airbrush to cast a shadow or create other unique effects not attainable with any other tool!
Reprinted with permission of ARTtalk.com