Presetting the fluid tip on the external mix airbrush or the needle adjustment screw on the internal mix airbrush controls the amount of paint sprayed. Internal mix airbrushes are available in both single and dual action . With the dual action trigger, you press down for air and then pull back to release paint. This provides more control over the volume of paint sprayed, since the further back you pull, the more paint that is released. Familiarize yourself with the components of the airbrush.
Airbrushes come in several styles that determine how the paint is supplied.
With gravity feed , the paint is held in a permanently attached reservoir at the top front of the airbrush, and here gravity supplies paint to the paint tip. With side feed , which comes with a color funnel that holds the paint and is plugged into the side of the airbrush, the funnel can be rotated so the artist can spray straight down or straight up. A bottom feed airbrush has jars that are force-fit underneath, a handy feature for quick color changes where the artist can lay out his palette in individual jars and plug them into the airbrush one after another. The pressure feed airbrush has a hose attached to an external tank that has paint under pressure. Special seals are required in the airbrush to prevent paint leakage.