NIC Barber Written (Theory) ExamScientific ConceptsHard
A barber is preparing a permanent waving solution for a client with resistant, coarse hair. To ensure effective penetration and restructuring, the solution needs to be highly alkaline. Which of the following pH values would be most appropriate for this type of solution?
- A7.0
- B9.5
- C12.5
- D4.5
Show answer & explanationAnswer & explanation
Correct answer: B. 9.5
Highly alkaline solutions (pH 9.0-9.6) are typically used for permanent waving on resistant or coarse hair. A pH of 9.5 falls within this range, helping to swell the cuticle and allow the waving solution to penetrate effectively.
Why the other options are wrong
- A. A pH of 7.0 is neutral and would not effectively open the cuticle of resistant hair for a permanent wave.
- C. A pH of 12.5 is extremely alkaline, typically found in lye relaxers, and would be too harsh and damaging for a permanent waving service, likely causing severe damage.
- D. A pH of 4.5 is acidic and would close the cuticle, making it unsuitable for opening the cuticle in a permanent waving service.
Alkaline pH in Perming
The use of highly alkaline solutions (typically pH 9.0-9.6) in permanent waving to swell the hair cuticle and facilitate the penetration of the reducing agent.
- Alkalinity causes the hair shaft to swell and softens the disulfide bonds.
- Higher pH is used for resistant, coarse hair; lower pH for porous, delicate hair.
- Excessive alkalinity can lead to hair damage.
Memory trick: For resistant hair, go 'up' the scale, make it 'alkaline' and 'swell'!