The pigment particles are charged by most any visible light or ultraviolet light. The pigments then release energy in the form of visible light for 30 minutes and as much as 24 hours. These pigments do have to be charged enough for a long lasting glow.
More powder, higher percentage will produce brighter, longer glow.
Use a white, or light color as a background for best results. Any color other than white will diminish glow.
Potentially, the higher amount of glow used
the brighter the glow and potentially a longer glow.
All pigments have been tested under UV light and under Sun Exposure (UV Rays)