Light Graffiti, London, United Kingdom

Technique and equipment
A variety of light sources can be used, ranging from simple flashlights to dedicated devices like the Hosemaster, which uses a fiber optic light pen. Other sources of light including candles, matches, lighter flints, glowsticks, and Poi are also popular.
A tripod is usually necessary due to the long exposure times involved. Alternatively, the camera may be placed on or braced against a table or other solid support. A shutter release cable or self timer is generally employed in order to minimize camera shake. Color Gels can also be used to color the light sources.