Yes, ash blonde shades like 9.0 are specifically designed to introduce cool, neutralizing pigments to counteract unwanted warm or brassy tones in light hair. The creamy texture of this formula helps it spread more evenly from roots to ends, which is key for achieving a uniform result.
For best results on lengths that are already light but brassy: ensure your hair is clean, dry, and free of heavy styling products. Section your hair and apply the color mixture thoroughly, working it through each section from the mid-lengths to the ends first, then finally to the roots. The roots often process faster due to scalp heat, so applying there last helps prevent them from becoming noticeably darker or cooler than the rest. Follow the processing time in the instructions precisely. Over-processing can sometimes lead to a dull, flat result, while under-processing might not fully neutralize the brass. If you have very porous ends from previous lightening, they may grab the ash tone more intensely, so a strand test is highly recommended to preview the outcome.