Hair Coloring and Chemical Texturing
Domain 4, Hair Coloring and Chemical Texturing, tests color theory, developer selection, patch and strand testing, relaxers, perms, and neutralization. The exam expects safe formulation, not just a color name.
Core rules
- The law of color: primary colors are red, yellow, and blue; secondary colors are orange, green, and violet; complementary colors neutralize each other.
- Hair levels run from 1 (black) to 10 (lightest blonde). Developer volume controls lift: 10 volume deposits, 20 lifts about 1–2 levels, 30 lifts about 2–3, and 40 lifts about 3–4.
- Underlying pigment emerges when hair is lightened: red at darker levels, orange at medium levels, yellow at lighter levels, pale yellow at the lightest.
- Relaxers are highly alkaline and break disulfide bonds; the neutralizer stops the process and rebuilds bonds.
- Always patch test color and lightener according to manufacturer directions; strand test whenever the formula or history is uncertain.
Worked example
A client at level 4 wants level 7. That is a three-level lift. Select a level-7 permanent color with 30 volume developer and assess the exposed underlying orange. Reasoning: 30 volume gives approximately 2–3 levels of lift, while 20 volume would likely leave the hair too dark. The orange undertone must be considered in the formula; if it is not neutralized, the result can appear brassy. A strand test confirms timing and tone.
Traps that cost marks
- Using 40 volume on the scalp for every high-lift service; scalp sensitivity and breakage risk increase.
- Overlapping relaxer onto previously relaxed hair, causing chemical burns and breakage.
- Shampooing too soon or skipping the neutralizer after a relaxer.
- Trusting a color chart without checking the client’s history, porosity, and underlying pigment.