Phosphorescence is light emission that continues after the UV source is turned off. It is often weaker than fluorescence and may last from a fraction of a second to minutes. Collectors check phosphorescence by charging the specimen under UV and then cutting the light quickly in a dark space. This behavior can separate similar fluorescent materials that otherwise look the same under UV.
When testing Phosphorescence, reduce ambient light so weak afterglow is visible, and note both the color and approximate duration. Some specimens show only a brief “flash” after UV is removed; that is still worth recording because it can be diagnostic. If results seem inconsistent, repeat the test after cleaning a face because coatings can absorb UV and reduce charging. Keep your phosphorescence note tied to the exact specimen and locality data so the observation remains useful.
Phosphorescence vs. fluorescence Phosphorescence continues after UV is off. Fluorescence stops immediately when UV is removed.
Phosphorescence vs. camera exposure Long-exposure photos can exaggerate glow. Confirm by watching the specimen directly in the dark.
Phosphorescence vs. ambient light leak Light leaks can hide weak afterglow. Test away from bright screens and windows.
Phosphorescence vs. “it faded so it’s not real” Afterglow is expected to fade. Record the starting brightness and how quickly it diminishes.