What is the purpose of a test strand during hair coloring?

The purpose of a test strand during hair coloring is to determine how the hair will react to the dye. This practice is essential because hair can vary significantly in terms of porosity, texture, and previous treatments, which can all influence the final color outcome. By performing a test strand, a cosmetologist can assess how the hair absorbs the color, how long the color should process, and whether any adjustments need to be made to the formulation for optimal results. This step helps prevent unexpected results and allows for better client satisfaction, as it provides insight into the effectiveness of the chosen hair color on the individual client's hair.