... (sunlight) or lamplight for 10 minutes, then continuously glow in the dark more than 12 hours.b. stable physical and ... painting, printing ink to make the medium glow in the darka. indication positioncan be applied in switch, control board, plug, lock, electric torch ... fire alarm, selfsaving tools, etc.b. safety fieldshow safety indication in the dark, such as signs, warming item, emergency passage way ...