New Hampshire Cosmetology Practice Exam

A lightener retouch should first be applied to the new growth of the hair. This is because the new growth is the most resistant part of the hair and will take the longest to lighten. The ends and mid-lengths of the hair have already been processed and are more fragile and prone to damage if over-lightened. Additionally, previously untreated hair may have varying levels of porosity and will react differently to the lightener, making it difficult to achieve an even result. Therefore, it is important to start with the new growth and then move on to the ends and mid-lengths if necessary.