"Rainbow Sun" is a UV (ultraviolet) blacklight fluorescent and glow-in-the-dark phosphorescent postcard print, made from the original psychedelic spiritual visionary fantasy fine art backdrop painting by Symeon Nostrakis, and depicting an Esoteric Magic theme:
A Radiant Sun in Meditation with a Heart and a Fire burning in his Third Eye,
breathing out a Rainbow which curls around him and the Stars,
forming an intricate Celtic Knotwork pattern.
If you don't have a UV black-light, the postcard will still glow in the dark and of course be visible in normal light.
For better glow-in-the-dark results place postcard near a bright light source and allow at least 30 minutes for charging.
The brighter the light and the more time the postcard is exposed to it, the more energy it will absorb and the more it will glow.
Additionally, the darker the room when you switch off the lights, the more pronounced the night glow effect will appear.
A black light source will charge the postcard better and will make it glow more than a normal light source would.
Alternatively, you can use fluorescent lighting for charging (FT tubes or small CFL economy lamps).
Old incandescent lamps cannot provide sufficient charging as they do not emit UV light.