If your highlights have turned too yellow, this can often be a result of under-processing. In such cases, if the hair’s condition allows, you can reapply the colour using a metal detox treatment to help neutralise the unwanted yellow tones.
For toning yellow highlights, I recommend using Dia Light with shades like 9.11, 9.01, or 10.01. These shades are designed to counteract and neutralise yellow tones in the hair. When applying the toner, visually process it to achieve the desired colour result. Be sure to follow the product’s instructions for application and processing times to ensure the best outcome.