Florida Cosmetology Licensing ExamChemical ServicesMedium
A client has previously colored hair (level 6) and wants to lighten it to a level 8 using an on-the-scalp lightener. To prevent excessive damage and ensure even lift, which volume of hydrogen peroxide developer is generally recommended for this service?
- A40 volume developer
- B20 volume developer
- C30 volume developer
- D10 volume developer
Show answer & explanationAnswer & explanation
Correct answer: B. 20 volume developer
For on-the-scalp lightening, especially on previously colored hair, 20 volume developer is generally the safest and most common choice. It provides sufficient lift (1-2 levels) while minimizing irritation and damage compared to higher volumes.
Why the other options are wrong
- A. 40 volume developer is extremely strong and should never be used on the scalp; it is reserved for off-scalp techniques.
- C. 30 volume developer is too strong for on-the-scalp application on previously colored hair and can cause significant irritation and damage.
- D. 10 volume developer provides minimal lift and is typically used for depositing color or toning.
Developer Volume for On-Scalp Lightening
The concentration of hydrogen peroxide in the developer used for lightening services, particularly when applied directly to the scalp. 20 volume is typically the highest recommended for on-scalp application to ensure safety and prevent irritation or chemical burns.
- Developer volume relates to lifting power
- 10 vol: 1 level lift, toning, depositing
- 20 vol: 1-2 levels lift, standard for on-scalp lightening
- 30 vol: 2-3 levels lift, generally off-scalp or very careful application
- 40 vol: 3-4 levels lift, never on-scalp, for extreme off-scalp lightening
Memory trick: Ten is for Tone, Twenty for Scalp, Thirty for Off-Scalp, Forty for Danger.