How does porosity affect processing time in a perm?

• A. High porosity hair absorbs chemicals quickly, requiring shorter processing; low porosity hair processes slower, requiring longer processing.
• B. Porosity has no effect on processing time.
• C. Higher porosity requires longer processing.
• D. Porosity only affects color outcome.

Answer: (A)

The concept being tested is how hair porosity affects processing time when you’re performing a perm. Porosity describes how easily hair accepts moisture and chemical solutions. Hair with high porosity has a more open cuticle and larger internal spaces, so the perm solution can penetrate the cortex quickly. Because the chemical reaction happens faster, you’ll need a shorter processing time to reach the desired curl without overprocessing or damaging the hair. Hair with low porosity has a tighter cuticle and harder penetration, so the chemical takes longer to work—processing time needs to be longer to achieve the same degree of curl.

That’s why the correct idea is that high porosity requires shorter processing, while low porosity requires longer processing. Saying porosity has no effect, or that higher porosity requires longer, or that porosity only affects color, doesn’t fit how the chemistry and penetration of the perm solution actually behave.