What colour result can I expect on my current hair shade?

Because this is a direct dye without peroxide or ammonia, it does not lift your natural pigment. On hair that has been pre-lightened to a pale yellow (level 9–10), the pigment deposits intensely and gives a vivid, electric blue. On light to medium blonde (level 7–8) you will see a noticeable but deeper, cooler blue veil — think midnight or denim rather than neon. On dark blonde or light brown the effect is a subtle blue tint visible mainly in bright light; on medium to dark brown or black hair the change is barely perceptible. Previous colour history matters too: porous, previously coloured ends grab more pigment than virgin roots, so the result can be uneven along the length. If you are unsure, test on a hidden strand first.