The rainbow that results is because ordinary light has been broken up into its various color wavelengths. A 5000K CFL bulb is very close to the luminescence of the noon day sun. These great value plastic pens look wonderful printed entirely colour. Natural aromas that remind of sweet foods go off endorphins that impact our sense of feeling smart. That's several year's value in the light lamp.
So, when formulators use pigments to create plastic color concentrates, are usually using substances that reflect certain aspects of the light spectrum. The sweetness we associate once again smells pull in Earth Element (summer), they're mood-altering throughout all their associations with sweet taste. For example, some of us may get glaucoma and cataract due to this reason.