Hair Shaping, Styling, and Chemical Services
Cutting and styling foundations
This domain tests haircutting, thermal and wet styling, chemical texture, and color. Haircutting depends on sectioning, distribution, elevation, and guide. Distribution is how hair falls or is moved before cutting; elevation is the angle at which it is held; a stationary guide does not move, while a traveling guide moves with each section. Wet sets use a base, stem, and circle; base control determines volume and direction. Thermal styling requires clean, dry hair and controlled heat to avoid bubble hair and cuticle damage.
Chemical texture
Permanent waves use ammonium thioglycolate (alkaline) or glyceryl monothioglycolate (acid) to reduce disulfide bonds; rods shape the hair, and a neutralizer (hydrogen peroxide or sodium bromate) rebuilds bonds. Relaxers use sodium hydroxide (lye) or calcium hydroxide/guanidine (no-lye) at high pH to straighten. A neutralizing shampoo restores pH and stops processing. Always patch test and strand test, analyze porosity and elasticity, and never apply relaxer to irritated scalp or overlap previously relaxed hair.
Color
Hair levels run 1 (black) to 10 (lightest blonde). Tone may be warm, cool, or neutral. Developer volume controls lift: 10 volume deposits, 20 volume deposits and lifts 1–2 levels, 30 volume lifts 2–3, and 40 volume lifts 3–4 with more damage. Aniline derivative tints require a patch test 24–48 hours before service. Color does not lift color; lightening requires decolorization, then toning.
Worked example. A natural level 5 client wants a level 7 warm brown. Reasoning: target is two levels lighter, so a permanent color with 20 volume is appropriate, mixed per manufacturer’s ratio. A patch test is done 24–48 hours ahead; a strand test checks timing and tone. Using 40 volume on the scalp would add unnecessary irritation and damage.
Traps that cost marks. Overlapping relaxer causes breakage and burns. Neutralizer is not optional. Do not skip a patch test because the client “used the color before.” A toner does not lighten; it only adjusts tone. 40 volume is not a shortcut for more lift on the scalp.