You can use the toner on highlights or balayage. But, be aware that because you're mixing toner with developer, it may lighten darker parts of your hair. Mix one part of the Wella Color Charm Permanent Liquid Hair Toner with two parts of the 20 volume Wella Color Charm Developer.
How do you dye your hair with Wella Color Charm?
Mix 1 part Wella Color Charm Color (or any permanent hair color) with 2 parts Well Color Charm Cream Developer. Apply to the hair using your desired technique, develop for 30 minutes and up to 45 minutes if additional depth or gray coverage is needed.