Why it's a bad idea:
* Box dye is notoriously difficult to remove: Box dyes contain metallic salts and a higher concentration of pigment compared to professional dyes. They penetrate the hair cuticle deeply and can be very stubborn to lift.
* Uneven lifting: Previously dyed hair will lift unevenly, leading to patchy and brassy results. The roots will likely lift much faster than the rest of your hair, creating a "hot roots" effect.
* Damage: Lifting dark hair to platinum blonde requires strong developers and multiple processes. Doing this on box-dyed hair, which is likely already compromised, will severely damage your hair. You're risking breakage, dryness, and even hair loss.
* Brassiness: Lifting brown hair *always* goes through warm stages (red, orange, yellow). Achieving an ashy tone requires completely neutralizing these warm tones, which is very difficult to do when lifting from such a dark base, especially with box dye in the mix.
What you should do instead (and it's still a process):
1. Consult a professional: This is the most important step. A professional colorist can assess the condition of your hair, determine the type of dyes used, and create a plan to safely lighten it. They can also perform strand tests to predict how your hair will react to lifting.
2. Be prepared for a lengthy and expensive process: Achieving ashy platinum blonde from brown hair takes time, patience, and often multiple salon visits. It can be a costly undertaking.
3. Gradual lightening: A colorist will likely recommend a series of gentle lightening treatments over several weeks or months, focusing on maintaining the health of your hair. They may use:
* Color remover: A professional-grade color remover can help pull out some of the artificial pigment without causing as much damage as bleach.
* Low-volume bleach: Using a lower volume developer and carefully monitoring the lifting process can minimize damage.
* Olaplex or similar bond builders: These products help to repair and protect the hair structure during the lightening process.
4. Toning: Once your hair is light enough, a toner will be used to neutralize the yellow and orange tones and create the ashy platinum blonde you desire.
5. Maintenance: Ashy tones fade quickly and require ongoing maintenance with purple shampoo and conditioners to prevent brassiness.
Important Considerations:
* Expect to compromise: Your colorist might advise that achieving your exact desired shade of ashy platinum blonde is not possible without causing significant damage. Be prepared to adjust your expectations and consider a lighter, healthier blonde option.
* Hair health is paramount: Prioritize the health of your hair over achieving a specific color. Severely damaged hair will never look good, regardless of the color.
* Patience is key: This is not a quick fix. It will take time and effort to achieve your desired results safely.
In summary, going from box-dyed brown to ashy platinum blonde is extremely difficult and risky. Consulting a professional colorist is the only way to achieve a good result while minimizing damage to your hair. Be prepared for a long and potentially expensive process, and prioritize the health of your hair above all else.