Hair Color and pH Level

Hair and ph Level
Q: My daughter is doing a hair course and is trying to find out the pH level for 1) temporary, 2) semi-permanent, 3) quasi-permanent, and 4) permanent color dye for hair.
A: The majority of hair color formulas are alkaline because they need to be able to penetrate the hair shaft and deposit the color molecules in the hair. The formulas that have less need to penetrate the hair are often less alkaline than those that have greater need to penetrate.
Semi- and quasi-permanent hair color generally has a pH of between 8.0 and 9.0. This causes a slight alkaline reaction to swell the cuticle and allows the color to enter the cortex as well as coating the outer layer of the cuticle.
Temporary hair colors generally aim for a less-alkaline formulation and may be found at around the 7.0 - 8.0 ranges.
Permanent hair colors that use an oxidative process can have a pH rating from 9.0 to as high as 11.0.
The precise pH levels of hair dye formulas often depend on the manufacturer, but will generally fall into categorical ranges such as are outlined above.
I do want to caution you that since your daughter is doing a hair course, her instructors may be looking for a specific set of answers from any texts she is using or may be looking for her to actually do some sort of lab work to decipher the answer to these questions. (My own formal education in getting my licensure included the use of litmus papers with various hair color formulas to get pH readings.)
You will want to make sure that she isn't bypassing something key to her class work by seeking her answers from us here at Aside from that, we are happy to be of help.
Photo: VectorMine/Shutterstock
See also:
Hair color formulas
The natural pH level of hair
The meaning of pH in shampoo
The pH level for water in a hair salon