Dying hair blonde removes some of the natural pigment, and then deposits another pigment in its place. For brunettes, removing the overlying brown pigment often reveals an orange undertone, giving the blonde a brassy appearance. Depending on your skin tone and hair color preference, the brassy color may be flattering or annoying. Light brown hair would produce a less intense orange than darker shades making it easier to prevent. Although your hair determines if dying your hair results in an orange caste, there are a few tricks you can use to help the hair dye remove as much of the brassiness as possible.
Choose a blonde hair dye described as ash blonde to complement and cover your natural orange undertones.
Deep condition your hair at least one week before you dye your hair to repair any cuticle damage, and create a more even base for the dye. Deep conditioning involves using conditioner on the hair for an extended period of time, such as an hour.
Wet the hair from root to tip before applying the hair dye.
Apply the hair dye evenly and allow it to rest for the manufacturer's minimum amount of time.
Separate a small section of hair, and scrape off the dye with a gloved fingernail to reveal the processed color of the hair. If it is unclear, wipe the hair with a wet rag to rinse the dye away.
Check the color of the hair in bright natural light. If the color is still brassy, or not as light as you would like, continue processing the hair for the maximum amount of time recommended. Do not go over the manufacture's recommended processing time or you risk damaging the hair.
Rinse the hair with filtered and deionized water. Mineral and iron deposits in tap water react chemically with the hair dye, causing the brassy color to reappear, even if successfully removed by the dye.
Apply a blonde toner, if the brassiness remains as the toner will cover the brassiness. However, it is a temporary solution and will need to be reapplied every 25 washes to maintain a bright, blonde hair color.