An air compressor is a device that converts power (usually from an electric motor, a diesel engine or a gasoline engine) into kinetic energy by compressing and pressurizing air, which, on command, can be released in quick bursts. There are numerous methods of air compression, divided into either positive-displacement or negative-displacement types. Positive-displacement air compressors work by forcing air into a chamber whose volume is reduced to compress the air. Piston-type air compressors use this principle by pumping air into an air chamber through the use of the constant motion of pistons. They use unidirectional valves to guide air into a chamber, where the air is compressed (source Wikipedia).
So why do I need a compressor?
An airbrush is a small, air-operated tool that sprays various media including ink and dye, but most often paint by a process of nebulization. Spray guns were developed from the airbrush and are still considered a type of airbrush.When using an airbrush to spray very fine liquids....these can be acrylic paint or even make-up to Body spray tans, the use of an airbrush to achieve the desired effects are crucial.Liquids are loaded into the airbrush and sprayed onto the desired surface, this is achieved by the use of forced air being driven through a small hole nebulizing the liquid to product a mix of paint and air to then be sprayed onto a surface.To produce the compressed air we can use a mechanical compressor or compressed air within an aerosol can. Aerosol cans are limited in capacity and for serious hobby artists or professional spray tanners then a compressor is vital. The outlay cost will soon be recouped compared to the relatively short-life of a can of compressed air.