Airbrushing employs special paint with finely ground pigment that is forced with a compressor through a specialized gun. Many beginners use stencils to practice steady hand movements and control of the paint flow. Making basic shapes such as circles and triangles is a good way to build up to the techniques required to make detailed images. A double-action airbrush allows you to adjust the amount of paint and width of the spray using a trigger with your pointer finger.
Locate a room with good ventilation that you don't mind getting a little dirty. Tape a sheet of 18-inch by 24-inch paper (or larger) to the wall. Cover 2 feet in each direction around the paper if you don’t want any spray to hit the wall.
Tape the stencil to the paper, making sure that it lays flat and won’t move around when you start spraying. Masking tape is easy to use and reuse with stencils, but be sure to tape down all four edges of the stencil.
Attach the hose to the compressor and the gun. This requires you to turn the nut to tighten each end. Turn on the compressor and practice using the trigger without paint, spraying only air. Use your pointer finger to press down and then pull back on the trigger. The farther back the trigger is pulled, the more air will be released and the wider the spray area becomes.
Choose a color to practice with, preferably a strong shade that will show up clearly on the paper. Shake the paint thoroughly to mix. Some brands have a ball inside the container to help mix the paint evenly.
Pour your paint into your gun's container, being certain to fit the cap back on tightly, and attach the container to the gun. Some containers sit atop the gun, which can be a good option for detail work using a small amount of paint. Other guns use suction to draw paint from a container that fits underneath the nozzle of the gun. Wear rubber gloves to protect your skin.
Put on the gas mask, and use the stand for the gun when you need to set it down. It may wobble with the hose and paint attached, so be careful not to let it fall, which could damage the tip of the nozzle.
Hold the gun about 2 feet away from the paper, push the trigger down and pull back slowly, moving closer to the paper and watching the flow of paint. Practice following the outline of the stencil shape, spraying an even coating along the edge without over-spraying and causing drips.
Lighten the flow of paint by letting the trigger forward, while still pressing it down, and move the airbrush toward the center of the stencil shape. The color will be lighter and with practice, you can create an even light-to-dark gradient.
Don’t use cheap paint from a craft store. The pigment is too grainy and will clog the gun. A good cheap substitute to practice with is India ink, although it can be a bit runny.
Wearing a mask is important and it is best to have one that covers your eyes as well as your nose and mouth. The compressor forces a mixture of air and paint through the gun into the air. These particles are dangerous to breathe.
Make sure there is some air movement from a fan, window or door. The area must be well ventilated.
Wear gloves, especially when mixing paint because as mediums and extenders contain harsh chemicals.