Double action refers to how you work the airbrush. A double action airbrush combines two seperate motions into a single control, the trigger.
Like the picture shows.
The up and down motion controls the air flow. It’s an on/off motion.
Double action airbrushes are also commonly refered to as dual action airbrushes.
Double action airbrushes, through the trigger, allow you to easily control the amount of paint introduced into the air stream.
This variable control allows you to paint dagger strokes.
I sum up good airbrush technique this way.
In other words, good airbrush technique is part of how you should spray. Single action airbrushes can’t do this so well.
The more ‘things’ you have to control or ‘keep in mind’ the harder it is to learn. The control allows advanced techniques, but it’s an added variable that takes longer to learn while causing more frustration.
Most people should choose double action airbrushes. There are a few extra headaches to overcome but it’s worth it. As an added bonus, if you know how to use dual action airbrushes, single action airbrushes are really easy.
If you’re a scientist or researcher you’ll probably want to go with a single action airbrush.