Spray oil painting is a painting technique where a device sprays a coating (paint, ink, varnish etc.) through the air onto a surface. The most common types employ compressed gas — usually air compressed by an air compressor — to atomize and direct the paint particles. Spray guns developed from airbrushes and the two are usually distinguished by their size and the size of the spray pattern they produce — with airbrushes being hand held and used instead of a brush for very fine work such as photo retouching, oil paintings nails or fine art.