California Cosmetology Written ExamHaircoloringMedium

A client's hair turns an unwanted olive-green cast after a toner application over yellow, over-lightened hair. Which base color should the cosmetologist use in the corrective formula to neutralize the green?

  1. AOrange-based
  2. BYellow-based
  3. CRed-based
  4. DBlue-based
Show answer & explanation

Correct answer: C. Red-based

Green is a secondary color made from blue and yellow; its complement on the color wheel is red. A red-based corrective color or filler will neutralize the green cast.

Why the other options are wrong

  • A. Orange neutralizes blue, not green.
  • B. Yellow contributed to the green cast and would not fix it.
  • D. Blue would intensify the green cast further.

Green Cast Correction

Unwanted green tones result from too much blue-green toner over yellow hair; corrected using red-based products.

  • Green = blue + yellow
  • Complement of green is red
  • Red-based filler restores balance before recoloring

Memory trick: Green needs Red medicine (complementary opposites cancel).

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