Long afterglow pigments VS short afterglow pigments

Glow in the Dark Pigments can be catagorised into long after glow and short after glow. Long afterglow pigments are Strontium Aluminate based pigments that contain some rare earth activators (Europium, Dysprosium, or other similar). Similarly short afterglow pigments are composed of zinc sulphide doped with copper. The primary characteristic that differentiates glow in the dark material from other colored pigments is that the pigment absorbs light energy (sunlight, interior light, etc.) and then slowly releases it as glow.Many photochromic pigments also respond to UV or black light with a near immediate light emission.