Light Graffiti has come to fame over the last couple of years and there are quite a bit of amazing works to show on the internet demonstrating what can be achieved.
Light graffiti artists create unique tagging in air or sometimes around object in dimensional way and then images are clicked with time-lapse photography. Sometimes this tagging is not even possible with spray paints.
Requirements for capturing light graffiti in your camera:
1) For capturing the light graffiti in your camera; the most important accessory is tripod. If you cannot get a tripod make sure that your camera is in a fixed position.
2)You need to set your camera with faster shutter speed.
3)The exposure time should be around 10-30 seconds and this should vary with the lighting conditions.
4)Keep your aperture dumb, do not highlight the aperture and make sure to keep your aperture closed. This controls the over exposure of the image.
5)Always prefer low ISO and stick to ISO 100 for better light graffiti.
6)If the lighting frequency is high, then attach a ND filter to cut down the unnecessary lighting.
Different light sources give you different colors of graffiti. Glow stick can be used to give variety of color, xenon gives you warm golden lights, cathode tubes give you thick lines and LED gives you thin precise lines.
Here are 25 amazing collection of light graffiti pictures.
http://immenceintense.blogspot.com/2008/12/25-amazing-light-graffiti-pictures.html