With practice, you can paint a fine, almost pencil-thin line with an airbrush. You can adjust the flow of the air so that the paint goes on thick or thin. By holding the airbrush just right, you can obtain all sorts of unique and interesting painting effects, which cannot be duplicated by either spray painting or brush painting. An airbrush is ideally suited for painting small parts already attached to the model and when painting camouflage colors over the model. Hobby airbrushes often use cans of compressed gas as the propellant.
Professional airbrushes use air tanks and compressors.
The air supply is connected to the brush by a hose. You control the air through the brush by pressing a trigger button. When you press down, the air flows through the brush. When you release the button, the air stops. Paint is sucked through the brush when air flows through it.