Likely Causes:
* Uneven Bleaching/Lifting: This is the most probable culprit.
* Heat from the Scalp: The bleach processes much faster at your roots due to the heat radiating from your scalp. Your roots likely lifted much higher (more levels lighter) than the rest of your hair.
* Uneven Application: It's challenging to apply bleach perfectly evenly, especially on the back of your head. You might have applied more bleach, or left it on longer, at the roots.
* Virgin Hair at the Roots: Your roots are virgin hair (unprocessed), meaning they're generally healthier and lift easier than hair that has been previously colored or chemically treated.
* Previously Processed Hair: The mid-lengths to ends are likely already damaged from previous coloring/styling and can be porous. This can cause them to be resistant to further lightening and/or grab toner unevenly. They may also be over-toned in the past.
* Incompatible Toner/Dye:
* Developer Volume: The developer volume used with the toner or blonde dye might not have been strong enough to deposit color onto the less-lightened sections.
* Toner Shade: The toner might have been too weak or too sheer to effectively neutralize or deposit color on hair that wasn't light enough.
* Product Build-up: Build-up from products can create a barrier that prevents the bleach/toner from penetrating the hair shaft evenly.
How to Prevent This in the Future:
1. Assess Your Hair's History and Condition:
* Honest Assessment: Be very honest with yourself about the condition of your hair. Is it dry, brittle, or damaged? If so, prioritize strengthening treatments before attempting more bleaching.
* Hair History: Know your hair's history (previous colors, treatments, etc.). This helps you anticipate how it will react to bleach.
2. Preparation is Key:
* Clarify: Use a clarifying shampoo a day or two before bleaching to remove product build-up.
* Deep Condition: Do a deep conditioning treatment a few days before bleaching to add moisture and strength.
* Don't Wash Directly Before: Avoid washing your hair on the day of bleaching. The natural oils can help protect your scalp.
3. Strategic Bleach Application:
* Root Shadowing: This is a technique where you blend the bleach from roots to the rest of your hair, by applying to roots last, to compensate for the heat from the scalp.
* First application to the ends: When applying the bleach, do the ends first, then mid lengths, then roots. This will help even out the lift.
* Lower Volume Developer: Consider using a lower volume developer (10 or 20) on the roots to prevent them from lifting too quickly.
* Watch Closely: Check the lifting process *frequently*. Don't just set a timer and walk away. You need to visually monitor how the hair is lifting.
* Don't Overlap: Avoid overlapping bleach onto previously lightened areas, as this can cause breakage.
4. Choosing the Right Toner/Dye:
* Consult a Professional: If you're unsure, consult a professional stylist. They can analyze your hair and recommend the correct toner/dye and developer.
* Understand Toner Types: Know the difference between demi-permanent and semi-permanent toners. Demi-permanent toners can deposit more color and last longer.
* Sufficient Pigment: Choose a toner with enough pigment to counteract the underlying tones in your hair.
* Proper Developer Volume: Use the recommended developer volume for your chosen toner/dye.
5. Post-Bleach Care:
* Protein Treatment: A protein treatment after bleaching can help rebuild the hair structure. Be careful not to overdo it, as too much protein can make hair brittle.
* Moisturizing Deep Conditioner: Follow with a moisturizing deep conditioner to replenish moisture.
* Avoid Heat: Minimize heat styling (blow dryers, flat irons, curling irons) as much as possible.
* Protect from Sun: Sun exposure can fade your blonde color and damage your hair. Use a hair product with UV protection.
Addressing Your Current Situation:
Here are the steps to fix your uneven color:
1. Assess the Damage: Evaluate the overall health of your hair. If it's very damaged, consider waiting a few weeks and focusing on strengthening treatments before attempting to even out the color.
2. Strand Test: *Always* do a strand test before applying any more bleach or toner to your entire head. This will help you determine how your hair will react.
3. Options for Evening Out the Color:
* Bleach Bath/Soap Cap: A bleach bath is a diluted bleach mixture that's less damaging than a full bleach application. This can gently lift the darker sections. Mix bleach with shampoo and developer (10 or 20 volume). Apply to the darker sections, monitoring closely.
* Toning: If the color difference isn't too drastic, you might be able to even it out with a toner. Choose a toner that's slightly darker than your current root color and apply it to the lighter sections.
* Lowlights: Adding lowlights that match the color of your mid-lengths to the roots can blend the root color with the rest of the hair.
4. Deep Condition: After any of these processes, deep condition your hair to restore moisture.
Important Considerations:
* Professional Help: If you're not confident in your ability to correct the color yourself, *please* consult a professional stylist. Color correction can be tricky and it's easy to cause further damage.
* Patience: Achieving your desired blonde shade may take multiple sessions. Don't rush the process, as this can lead to damage.
* Hair Health: Always prioritize the health of your hair over achieving a specific color. Damaged hair won't hold color well and will be more prone to breakage.
Good luck! Take your time, be patient, and prioritize the health of your hair.