i was fairly anxious about using clairol's nice 'n easy root touch up because i usually mix light auburn and dark auburn when i color my hair, but in this case i had to choose one. i went with light auburn.
the box stated over and over that it would match my shade exactly, which seemed like an outrageous claim. i got to mixing my trough of color and spreading it through my roots, all the while thinking, "the things i do for mlm!". but, it's true! at least for me, my roots match my hair perfectly.
who knows how the wizards at clairol do it, but if you're betwixt salon visits, you may want to holla at clairol's nice 'n easy root touch up, typically under $10 at drugstores nationwide.