Airbrush Basics

by
Jeff Colburn

The airbrush is an amazing artist's tool, and you would be hard pressed to find anything that makes more realistic atmospheric mists, clouds and cast shadows. I've seen some airbrush artists make clouds that look so real you could swear they're drifting across the image as you watch.

In case you don't know what an airbrush is, let me explain. They come in various styles, but basically it's like a very small paint sprayer. It has a spray nozzle in the front, just behind that is a cup for holding paint that is about the consistency of water and at the end is a hose that pressurized air flows through. The pressurized air goes out the front of the airbrush, and along the way feeds the paint into the air stream, which you spray onto your painting surface.

One nice feature about the airbrush is that you can use almost any liquid pigment. Acrylic, watercolor, gouache, ink and tempera paints all work well with airbrushes. The pigments in watercolors work exceptionally well with airbrushes because they are so small that you will have little or no clogging, no matter how fine of a nozzle you use.

If you decide to use watercolors as your medium, it's best to avoid tray colors. Since tray colors sit next to each other, it's easy to accidentally dribble a little of one color into another. Instead try tube colors. Tube colors are less likely to be contaminated by another color . Just squeeze some into a paper cup and start mixing with water. After creating a mixture of about 50/50, you can simply pour it into the airbrush's reservoir.

When using acrylics, avoid metallics or glitter paints as these particles can clog the nozzle. There's nothing as frustrating as getting the exact image you want, only to have to repeatedly stop to clean out the airbrush's nozzle. You may also find that using acrylic jar colors instead of tube colors will work better. This is because the jar colors are thinner and when mixed with water create a smoother paint that flows more easily through the airbrush.

It's easy to make deep, rich colors with an airbrush. Don't lay down one heavy coat, instead go over an area several times. This also makes it easier if you don't want a solid color, but more variability, like multi-colored clouds.

When learning to paint with an airbrush, you must do these three things correctly:

1. The paint you use must be flowable. With acrylics you will want to start with a 50/50 mix of water to paint. Then adjust as needed. Don't thin down acrylics too much or they can crack or flake off, especially if you are painting on a non-porous or flexible surface. While a porous surface, like paper or cloth, can be painted with a mixture of up to 80% water, less porous surfaces require more medium. Flexible surfaces need a 50/50 mix.
   
2. The air pressure needs to be correct for the viscosity of your paint. You can achieve this by using an air source that has a regulator. This way you can adjust the air pressure as needed for paint mixtures of different viscosity.
   
3. You must learn to use the airbrush's trigger properly. There's more to the trigger than pressing it down all the way. You'll figure this out with experience.

If you want to create a hard edge with an airbrush, you will need to use Frisk film. This is a thin sheet of plastic with a low tack adhesive on one side. You lay Frisk over the working surface, and cut out the areas you want to paint. This lets you paint one area while protecting the rest of the surface.

You must learn how to make a clean cut through the film, without cutting into the illustration board that you have it attached to. Cuts in the illustration board will absorb paint differently than the rest of the board, and these cut lines will become very obvious. Let's say you want to use an airbrush to create a yellow pencil. If three facets of the pencil are visible, and each facet is a different shade of yellow, then cut the Frisk off the first facet. Be sure to save the Frisk, as you'll need it later. Just put it on the wax backing you removed from the Frisk. Then you will paint this facet, let the paint dry, reattach the piece of cut Frisk, cut out the next facet, and so on. When you put the cut piece back on the painting, you will need to seal the seam you have cut. This can be done with 3M removable tape. When you've finished an area and want to remove the Frisk, but have more painting to do, you can cover the finished area with tracing paper. Be sure not to leave Frisk on an illustration board for too long or it may permanently adhere. Check with the manufacturer, but two days on a board is pushing your luck. Try to limit it to one day.

On the other hand, if you want to create soft edges, you need to use a template that doesn't sit directly on the surface you are painting. You can buy templates like this, or you can create them by getting a template that lies flat, and using a device like Pickett's template ink riser. This device creates indentations on the template, thus giving it little "legs" to lift it off the surface. You can also cut your own templates out of 10 millimeter acetate. To soften the edged even more, you can move the hand holding the template a little back and forth. Since you always have to hold the template, or put weights on it if you don't need to move it, you may want to wear disposable rubber gloves. The hand holding the template will look much nicer after the session if you do.

When you've finished airbrushing you can use a small brush for the finer details, like strands of hair, small highlights and so on. It's much easier to do this with a brush than try to airbrush them in.

As with any artist tool, use the airbrush for what it's designed for. You don't have to use it for your entire painting. I know an artist that uses an airbrush for clouds, smoke, fire, and similar wispy type things. He does this first, removes the Frisk, and uses brushes for the rest of the painting. He really gets some great effects.

Always keep safety in mind with art supplies. This is especially true with the airbrush. Because it puts small droplets of paint in the air, you should always wear a particle mask when painting. This is true even when using non-toxic paints. It's always better to be a little over cautious when dealing with your health.

During your work period, periodically clean the airbrush by flushing it with water. When it's time to take a break, put the airbrush in a container with the tip in water. This prevents paint from drying in the tip. One of the biggest problems with an airbrush is keeping the tip clean. A dirty tip will cause all kinds of problems, including uneven spray, running paint and many other unwanted affects.

When you are done for the day, flush the airbrush with glass cleaner containing ammonia, or airbrush cleaning solution. You can use denatured alcohol to remove dried acrylics from airbrushes, but it may damage the washers around the needle if they are not made of Teflon, which most are.

It will take time to master the airbrush, but since it has so many applications, from T-shirts to photographs, it's well worth the effort. So go out there and make clouds, waves, glass, metal, people, animals (politicians, lawyers, etc.) and anything else you can dream up. It's all at your fingertips, literally.