The trigger will control the air and the amount of paint that comes out is determined by the needle adjustment on the back of the airbrush handle. Dual action is when the trigger on the airbrush controls both the air and paint. The trigger is pressed down for the air and back for the paint. Now when it comes to the feed on the airbrush there are three types of feeds that you can choose from. While an experienced airbrush artist may know this a beginner may not, so it is worth mentioning. When doing airbrush art on skin make sure you are using airbrush paint that is designed for the skin. Usually this will be sold as airbrush body paint or airbrush temporary tattoo ink. These are the only types of airbrush paints that are safe to use on the human skin. So someone who has no real prior knowledge this book will help you understand the airbrushes that you will be using when creating airbrushed artwork. Getting Started in Airbrush by David Miller is also a great beginner's book on airbrushing. The book will give step-by-step instructions on the basic level of airbrushing techniques and how to create different effects with your airbrush art. PSI stands for pounds per square inch and for automotive airbrush art you need a compressor that has a psi of 55-65. Iwata is a great name brand to go with and they offer four compressors that will work for airbrushing automotives. Badger is another good name brand that you can go with. They offer several air compressors that will work when doing airbrush art on automobiles. Acrylic nail art paint is needed when doing airbrushing art on nails. These paints clean up with water while they are still wet. So if you do get any on the skin or another surface where not needed then clean up immediately while it is still wet. The paint will become permanent when it dries. There are a lot of possibilities with acrylic nail art paint that you can do when creating your airbrush art. Unlike henna that must be hand painted airbrush art tattoos can be completed in a fraction of the time. Airbrush art kits give you the necessary tools to get you started creating your own airbrush art tattoos. These kits come in a variety of sizes and price ranges depending on the dealer you are purchasing them from.