Light painting is the photographic technique of using a moving light source—such as a flashlight, glow stick, light brush, or even a smartphone—to alter an image while taking a long exposure photograph.
1.) Go to an EXTREMELY dark place to shoot for this assignment. Put the camera securely on a tripod and put your shutter speed at 20 to 30 sec (not 20th of a sec…but 20 full seconds). You must put the camera on self-timer to avoid camera shake. Shoot on manual and try your fstop at 8 or 11. ISO at 200 or 400.
2.) Pre focus on Manual focus mode, because the camera will not in autofocus! more info ...
3. ) Wave finger lights in front of the frame during the exposure and check out the results!
TIPS:
Use smartphone flashlight, pocket light - make sure you get a consistent and easy to maintain light source.
Use a camera with a long shutter speed option. If you have a DSLR, you certainly have an option for long shutter speeds. If you use a simpler camera it often has a night-function or light painting feature. These days, smartphone have these features too.
Use a tripod or sturdy to help you to maintain a steady shot. You want the light to move around, not your camera.
Use a friend or a remote shutter. Ask a friend to do the light painting for while you direct him/her. If you want to do it by yourself, you can use a remote shutter function which most cameras have or a timer that allows you to click the shutter button and then get into place.