Glow in the dark items rely on phosphorescence to create their unique effect once the lights go out. Phosphorescent coatings rapidly absorb and store light, then slowly release it. Though commonly used to complement spooky Halloween decorations, clock and watch faces often sport phosphorescent coatings so they can be easily read at night. Though photographing in the dark may seem challenging, it can be done simply with advanced preparation and the right equipment.
Charge the glow in the dark items under an ultraviolet (UV) light source for roughly half an hour. Black lights work especially well.
Set up your glow in the dark item(s) as desired. Ensure that the UV light continues to light the subject as you prepare your shooting area.
Place a tripod about 4 feet away from the items and mount your camera on it. Lower the camera to the height of the items.
Pre-focus your camera lens on the items and set your aperture (lens opening) to f/8. This will help you avoid fumbling around in the dark as your items lose their charge.
Switch off all sources of light and open your camera's shutter using either a remote (for digital users) or release cable (for film users). Leave the shutter open for 15 to 30 seconds.
Check your results if you're shooting digital. If they are too light, re-shoot and leave the shutter open for a shorter amount of time. If they are too dark, re-shoot and leave the shutter open for a longer time. Experiment with a range of exposure times from 10 to 40 seconds if you're using film. This ensures that a properly exposed shot will appear somewhere on your finished roll.