Platinum Blond 10.0 is a permanent dye that both lightens and deposits a clean, bright blonde pigment. This action can help counteract some warm, brassy tones that appear in previously lightened blonde hair, especially if the brassiness comes from faded color or slight yellowing of your natural underlying pigment. The deposited cool/neutral blonde pigment works to overlay and neutralize warmth for a more polished, luminous result. However, it is not a dedicated purple or blue toner, which are purely deposit-only products designed specifically for strong brass neutralization on already-lightened hair.
If your hair is already at a very light blonde level and your primary goal is to cancel out strong orange or yellow tones, a separate toner after coloring might still be necessary for a true platinum or icy effect. The degree of brass neutralization you get will depend on how much lift the dye achieves and the specific pigments in its formulation. For best results on brassy hair, ensure you apply the product evenly and for the full recommended time. A strand test will show you how effective it is at managing the unwanted warm tones on your specific hair. Remember, after any color service, using a violet-toned shampoo once a week can help maintain the cool tone and delay the return of brassiness.