It is a tone-on-tone hair dye that creates glossy, luminous looking reflects, an incredible vinyl shine and natural-looking color that gradually fades away.What it does: Its gentle acid technology smooths the hair cuticle for ultimate shine. The L'Oreal Pro Paris Dia Light is perfect for refreshing previously color-treated or weakened hair. Once applied to your hair, the Pro Paris Dia Light color gently penetrates the hair strands. Simultaneously, the cationic polymers produce a resurfacing effect to the hair cuticle, creating glossy, beautiful results.What else you need to know: DIA light can be used after all lightening treatments. Not a product for covering white hair. Development time 2 - 20 minutes. Zero lift.