Hair Coloring and Lightening
What this domain tests
Hair coloring and lightening tests the law of color, developer selection, patch and strand tests, mixing ratios, gray coverage, foil placement, and damage control. The exam expects you to predict deposit versus lift and to know when a service must be refused.
Core rules
- Primary colors are blue, red, and yellow; secondary colors are made by mixing two primaries. Complementary colors neutralize unwanted tones.
- Developer volume controls lift and deposit. Higher volumes generally increase lift but also increase damage; use the lowest volume that achieves the target and follow the manufacturer's ratio.
- Perform a patch test before color when required by the product label or client history; perform a strand test when the formula or timing is uncertain.
- Match the formula to the natural level, target level, and underlying pigment. Gray hair may need a specific gray-coverage formula.
- Never color over broken scalp, active infection, or a known allergic reaction. Keep records of formula and timing.
Worked example
A natural level 5 client wants level 7. The reasoning: the goal is two levels of lift, so choose a formula and developer designed for that amount of lift, check the underlying warm pigment, and strand test. Using 40 volume by habit is not justified if a lower volume with the correct formula can reach the target.
Traps
More developer is not always better; overlapping lightener causes breakage; a patch test is not optional when indicated. Also do not promise an exact result without assessing previous color.