Kerastase Blond Absolu Anti-Brass Purple Shampoo

When it comes to colour theory, purple cancels out yellow, which is why products designed to remove brassy tones from blonde hair are often a vibrant violet hue. Take the Blond Absolu Anti-Brass Purple Shampoo from Kérastase, for example; its rich colour helps neutralise unwanted yellow undertones while cleansing locks and boosting luminosity.