Glow Inc. Ultra Blue Glow in the dark powder 1 ounce Ultra Blue Glow in the Dark Powder, although not as bright as its Ultra Green counterpart, is still an extremely bright glow in the dark pigment. It is 5 times brighter than the popularblue zinc-based glow in the dark products available in most department stores. Brightness Rating: Very High (9416) Duration: Very Long (9 hours) Daytime Color: Almost Clear with White-Green Tint