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 developed from the airbrush and are still considered a type of airbrush.

The first airbrush, depending on your definition, was patented in 1876 (Patent Number 182,389) by Francis Edgar Stanley of Newton, Massachusetts. Stanley and his twin brother later invented a process for continuously coating photographic plates (Stanley Dry Plate Company) but are perhaps best known for their Stanley Steamer. Unfortunately no artistic images that used this ‘paint distributor / atomiser’ exist or are as yet known.

The airbrush that was first given the name Air Brush, was developed by Abner Peeler and used a hand-operated compressor, and the inventor patented it “for the painting of watercolors and other artistic purposes”. It was rather crude, being based on a number of spare parts in a jeweller’s workshop such as old screwdrivers and welding torches. It took 4 years of further development before a truly practical device was developed. This was marketed by Liberty Walkup, who taught airbrush technique to American Impressionist master Wilson Irvine at the Air Brush School in Rockford, Illinois. The first certain ‘atomising’ type airbrush came along in 1893, presented by Thayer and Chandler art materials company at the World Columbian Exposition in Chicago, invented by Charles Burdick. This device looked like a pen and worked in a different manner to Peeler’s device, being essentially the same as a modern airbrush. Aerograph, Burdick’s original company, still makes and sells airbrushes in England.

For more a detailed academic study, the University of Wales Library holds a detailed PhD on Airbrush History. The Franklin Institute in Philadelphia, The Public Library in Rockford Illinois and the Conservation Department of New York University retain copies. This was authored by Dr. Andy Penaluna, now Professor of Creative Entrepreneurship at Swansea Metropolitan University.[1] Professor Penaluna has also advised the International Museum of Photography at George Eastman House, Rochester, New York

An airbrush works by passing a stream of fast moving (compressed) air through a venturi, which creates a local reduction in air pressure (suction) that allows paint to be pulled up from an interconnected reservoir at normal atmospheric pressure. The high velocity of the air atomizes the paint into very tiny droplets as it blows past a very fine paint-metering component. The paint is carried onto paper or other surface. The operator controls the amount of paint using a variable trigger which opens more or less a very fine tapered needle that is the control element of the paint-metering component. An extremely fine degree of atomization is what allows an artist to create such smooth blending effects using the airbrush.

The technique allows for the blending of two or more colors in a seamless way, with one color slowly becoming another color. Freehand airbrushed images, without the aid of stencils or friskets, have a floating quality, with softly defined edges between colors, and between foreground and background colors. A well skilled airbrush artist can produce paintings of photographic realism or can simulate almost any painting medium. Painting at this skill level involves supplementary tools, such as masks and friskets, and very careful planning.

Some airbrushes use pressures as low as 20 psi (1.38 bar) while others use pressures in the region of 30-35 psi (2-2.4 bar). Larger “spray guns” as used for automobile spray-painting need 100 psi (6.8 bar) or more to adequately atomize a thicker paint using less solvent. They are capable of delivering a heavier coating more rapidly over a wide area. Even with small artist airbrushes using acrylic paint, artists need to be careful not to breathe in the atomized paint, which floats on the air for minutes and goes deep into the lungs. With commercial spray guns for automobiles, it is vital that the painter have a clean air source to breathe, because automotive paint is many times more harmful to your lungs than acrylic. Certain spray guns, called High-Volume Low-Pressure (HVLP) spray guns, are designed to deliver the same high volumes of paint without requiring such high pressures.
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