Chemical Services: Permanent Waving, Relaxing, and Color
What a candidate must know
Chemistry base. All chemical texture and color services act on the cortex. Perms and relaxers break disulfide bonds; neutralizers and neutralizing shampoos rebuild them. Color services deposit or lift pigment.
Permanent waving. Alkaline waves use ammonium thioglycolate at about pH 8.2–9.6 and process at room temperature. Acid waves use glyceryl monothioglycolate at about pH 6.5–7.2 and need heat. Sequence: patch/strand test, wrap, saturate, process, rinse, blot, neutralize, condition. Always perform a test curl and read manufacturer processing times.
Relaxing. Sodium hydroxide (lye) and no-lye products (guanidine, lithium) are strongly alkaline (roughly pH 12–14). Know the difference between base and no-base application, why scalp protection matters, why relaxer is applied to new growth only, and why a neutralizing shampoo with a pH indicator follows.
Color. Temporary, semipermanent, demi-permanent, and permanent (aniline derivative) colors. Developer volumes: 10 (deposit only), 20 (about one level of lift with deposit), 30 (about two), 40 (about three). Learn the law of color, level system, undertones, fillers for tint-backs, and double-process lightening.
Tests and safety. Patch test 24–48 hours before aniline color; strand and elasticity tests before texture services; never mix chemicals not intended together.
Traps
- Confusing acid and alkaline wave pH values and heat requirements.
- Assuming demi-permanent color lifts - it generally deposits only.
Rule of thumb
Lift rule: 20 volume lifts about one level and deposits; add one 10-volume step per additional level. If the goal is deposit only, use 10 volume.