professional advice or a second opinion.
Many times, even hair stylists in the salon ask one another for a second opinion prior to applying color. It's the same in most professions whether it be medical, legal, etc. Yet many individuals believe they know what's best for their hair so they self-prescribe with no true knowledge of the science behind hair care, color formulations, contributing pigment, direction of hair or distribution points. What's worse, is that they make these purchases with no second opinion. All of these points are crucial in achieving the best hair color possible, or the best haircut possible. Without this science, we would all have cut & color that looked more like an accident in a print shop than carefully defined application.
The $7 box of hair color you purchased can turn out to be a $400 color correction and it's simply not worth it to take hair into your own hands. The results are never truly what you want, and the feelings of frustration trying to get into a salon and explain your situation are even more exhausting. Believe me when I say, it's best to trust your hair stylist for your cut & color needs. You'll be glad you did.