I have written several articles involving light graffiti, but don’t really define what light graffiti is on this site. I’ve shown it being done with a quadcopter, but what exactly is it really?
Light Graffiti is using a light source to create an image. As I write in one of my first articles “defining” the subject:
“when you open up the shutter of your camera and draw an image with a light source, the camera records all light in front of it as if it happened at once.”
Stop the exposure, and you get whatever light was there between when everything started and stopped. It’s as if all the light you moved around was there at one instant. Once you somewhat understand what’s going on, check out a more practical guide to starting out, my beginner’s guide to “light painting,” as it’s also sometimes referred.
This technique is generally done with a camera that’s capable of varying the exposure time, like a DSLR (here’s mine from Amazon). If you don’t have a DSLR, but do have a point-and-shoot Canon camera, you can “soup it up” to allow for this kind of advanced shooting using CHDK.
I also did an article on this subject for Hackaday.com, which is hopefully a good read, as well as Popular Science, which was really cool to see published.