Spray paint is liquid paint that can be delivered onto a surface through a spray nozzle. The term is usually applied to paints of various colors that are available in inexpensive, easily portable aerosol cans. Paints used in airbrushes and spray guns are also forms of spray paint but, in common use, the term “spray paint” is synonymous with the aerosol-can form, also called “aerosol paint.” The paint can be used wherever paint is used, but it is particularly connected with municipal signage and the underground art form called graffiti.
Aerosol paint is available in a wide variety of colors from any store that carries paint or hardware supplies. The cans are easily stored and transported, and they are popular for a wide variety of paint applications. Pressurized gas forces the paint out of the can in an even stream, usually removing the need for brushes or rollers to distribute the paint across the surface. Most cans include a ball inside to mix the paint, resulting in the rattling sound when the can is shaken.
Spray paint can be used to create signs and symbols quickly and neatly, often by applying a stencil that blocks paint from all but the desired area. This process also lends itself to graffiti, the practice of painting messages or artwork onto buildings, bridges, sidewalks or any other surface, often illegally. Many cities have laws regulating the sale of this paint and other materials because of graffiti. While it is often identified with vandalism, not all graffiti is illegal; some property owners see it as an art form and allow or even commission it.
Airbrush and spray gun paints are also forms of spray paint. An airbrush is an instrument that uses compressed air to focus paint into a very precise area. They are often used for detail-oriented work, such as retouching photographs, because of this precision. Spray guns operate on a similar principle, but often employ wide nozzles to cover a greater area. They are used in industrial applications such as the mass production of cars, building materials and houses.
All forms of spray paint pose potential health risks, because they release tiny particles of paint into the air. While most of this goes onto the painted surface, some is lost into the surrounding air as “overspray.” Unprotected painters can inhale overspray into the lungs, where it can cause immediate or long-term health problems. Propellants in aerosol cans can pose similar dangers. The U.S. Environmental Protection Agency recommends spray painting in well-ventilated areas and using respirators, gloves and protective clothing to prevent chemical exposure.