GloBrite Glow-in-the-Dark aluminum signs have a natural light green color that provides vibrant glow when in the dark. Easily spot signs in a blackout situation because of the SmartGlow photoluminescent film on the 40 mil thick sign or a 9 mil adhesive vinyl sign. The light-absorbing material stores particles of light and discharges them as a greenish glow. The text on Photoluminescent Notice Signs is the non-illuminated section that contrasts with the glowing material.