Invented in 1949 by paint salesman Ed Seymour to apply aluminum coating to radiators, spray paint is paint that sprays onto any surface (walls, wood, metal, glass, plastic, or canvas) from an aerosol can. By 1979, an entire spray-paint industry had developed, with over 270 million cans being sold annually in the United States. This rise coincided with the prominence of graffiti art in the 1970s, a form centered in New York City. Spray paint was portable, affordable, and easy to use, making it the medium of choice for the illegal activity. Some early practitioners of graffiti art included Lady Pink, CRASH, Lee Quinones, and Fab 5 Freddy. In the 1990s and 2000s, contemporary graffiti artists such as Shepard Fairey and Banksy built on these earlier artists’ work. Galleries began showing graffiti paintings in the 1980s, and since then spray paint has been increasingly used by non-graffiti artists, including Peter Peri, Blue and Joy, Rita Ackermann, and Jaybo Monk, often in combination with other materials and techniques. Spray paint has a noticeable aesthetic, void of brushstrokes, and many application techniques, including burns, fades, and flares. Depending on the amount of pressure painters apply to the nozzle and the time they spend in a particular spot, spray-paint lines can be thin, thick, layered, splattered, and/or dripped. The graffiti artist KATSU has recently advanced spray-painting techniques using new technology by spraying paint from drones.