Hair Shaping, Styling, and Chemical Services
Hair shaping and styling
- Elevation controls volume: 0° for blunt/one-length, 45° for graduated, 90° for uniform layers, and 180° for long layers.
- Distribution and tension determine accuracy. Natural fall, shifted distribution, and perpendicular distribution create different effects; subsection consistently.
- Thermal tools should be used on dry hair, kept moving, and matched to hair condition. Lightened or damaged hair overheats easily; use a thermal protectant and follow manufacturer temperatures.
- Wet styling includes molding, finger waves, and roller sets; base control affects root lift.
Chemical services
- Perms reduce disulfide bonds with thioglycolate (often pH 9–9.5), then neutralize with bromate or peroxide to rebuild bonds. Test curl determines processing.
- Relaxers use sodium hydroxide (lye, pH about 12–14) or no-lye guanidine/carbonate systems. Base the scalp, apply only to new growth on a retouch, respect processing time, and neutralize until suds are clear.
- Color uses aniline derivatives. Patch test 24–48 hours before; strand test for unpredictable hair. Developer volume controls lift and deposit: 10 volume deposits, 20/30/40 volume gives increasing lift. Color does not lift color.
- Analyze porosity, elasticity, and density before any chemical service.
Worked example
A client with 1 inch of new growth and previously relaxed ends asks for a retouch. Reasoning: apply relaxer only to the new growth; protect previously relaxed hair with conditioner; do not pull relaxer through the ends. Process, rinse thoroughly, neutralize until the suds are clear, then condition. Overlapping causes breakage and scalp burns.
Traps that cost marks
Applying relaxer scalp-to-ends; skipping neutralization; using 40 volume on the scalp; omitting patch or strand tests; assuming “gentle” means no risk; cutting with inconsistent tension.