Key Effects & Considerations:
* Maximum Lift: 40 volume developer is the strongest commonly used developer. It opens the hair cuticle aggressively, allowing the color to penetrate deeply and lighten the natural pigment significantly. This makes it suitable for lifting several levels of darkness (typically 3-4 levels, sometimes more depending on hair type and color).
* Faster Processing: Due to its strength, 40 volume developer works faster than lower volumes. Keep a close eye on the hair to prevent over-processing.
* Increased Damage Potential: The aggressive action of 40 volume developer can lead to more damage, dryness, and breakage compared to lower volumes. The higher the volume, the more the hair cuticle is opened, leading to moisture loss and weakened hair structure.
* Stronger Color Result: The color will be more vibrant and intense, especially if you're going for a lighter shade or a bold color.
* Greater Risk of Brassiness: When lifting dark hair, there's a higher chance of revealing underlying warm tones (reds, oranges, yellows). This is especially true if the hair doesn't lift enough during the processing time. Using a toner after coloring can help neutralize brassiness.
* Scalp Irritation: 40 volume developer can be irritating to the scalp, especially for those with sensitive skin.
When is 40 Volume Developer Appropriate?
* Significant Lightening: When you want to lift your hair several shades lighter (e.g., going from dark brown to light blonde).
* Stubborn or Resistant Hair: If your hair is naturally resistant to color or has been previously colored multiple times, 40 volume might be needed to achieve the desired level of lift.
* Professional Use: It's generally recommended to be used by experienced colorists who can assess hair condition and prevent over-processing.
When to Avoid 40 Volume Developer:
* Damaged or Weak Hair: Using 40 volume on already damaged hair will likely cause further breakage and dryness.
* Sensitive Scalp: If you have a sensitive scalp, 40 volume could cause irritation, burns, or allergic reactions.
* Subtle Color Changes: If you only want a slight color change (e.g., covering grays or adding a subtle tint), a lower volume developer (10 or 20) is more appropriate.
* DIY without experience: If you are not experienced in hair coloring, it is recommended to seek professional help.
Important Considerations:
* Strand Test: Always perform a strand test before applying the color to your entire head to assess the processing time and color result.
* Hair Condition: Assess the health of your hair before using 40 volume developer. If your hair is already damaged, consider using a lower volume or focusing on repairing your hair before coloring.
* Proper Technique: Follow the manufacturer's instructions carefully. Apply the color evenly and process for the recommended time.
* Post-Color Care: Use moisturizing shampoos, conditioners, and deep treatments to help restore moisture and repair any damage.
In summary, using 40 volume developer with hair color can achieve significant lightening and intense color results, but it also carries a higher risk of damage and scalp irritation. It's best suited for experienced users who need to lift several levels and are aware of the potential drawbacks.