And when the lights go out, there is glowFill. When you print it, with regular lights on or during the day, it is a very nice, creamy filament with a very smooth finish. Nice as it is, it changes when the lights go out. Then you will see it glow. A special highly concentrated phosphorescent pigment is matched with our PLA/PHA compound, so it’ll print just like our other PLA/PHA 3D printing filaments. It is by far one of the most fun filaments which can lead to some fantastic prints.