Hair color correction calculator

Hair color correction is the process of eliminating or neutralizing unwanted tones in the hair. It can be as simple as applying a violet toner to remove yellows, or as complex as a multi-step process to reverse a failed bleaching.

Unlike the neutralization wheel that shows you which corrector to use, this calculator goes one step further: it calculates the developer, technique, and specific reflection based on your current level, target level, and the tone you need to eliminate.

The most common situations where you will need to correct color are:

• After bleaching: The underlying pigment always leaves warm tones. A level 6 leaves orange, a level 8 leaves yellow. The right corrector eliminates them.
• Color over color: Applying a new dye over a previous one can generate unexpected reflections, especially if there is pigment buildup on midshafts and ends.
• Sun and water damage: Sun exposure oxidizes artificial pigments and generates coppery or orange tones that were not in the original formula.
• Excess toner: Too much violet generates gray or excessive ash. Too much ash on a golden base can generate green.

The calculator uses the principles of the Oswald Star and professional hair colorimetry theory:

1. Current and target level: Determines if you need to lift, deposit, or maintain, and calculates the appropriate developer.
2. Unwanted tone: Identifies the complementary color that neutralizes that tone according to color theory.
3. Recommended technique: Based on the level difference, suggests direct deposit, lift with tone, or multi-step correction.

The result is a professional guidance that combines these three factors. For complete formulas with brand-specific products, download Blendsor.

These are the cases color professionals see most often:

• Blonde with yellow: Level 8-9 with yellow undertone. Solution: violet toner (.2) with 10vol. The most frequent and simple correction.
• Brown with orange: Level 6-7 with orange undertone post-bleaching. Solution: blue ash (.1/.01) with 20vol to reach the level and neutralize simultaneously.
• Dark with red: Level 4-5 with persistent red. Solution: controlled bleaching + ash-matte (.13) as toner. Multi-step process.
• Greenish blonde: Level 7-8 with green from excess ash or chlorine. Solution: copper (.4) with 10vol as a corrective color bath.