Temporarily Color Roots

Auburn-red hair
Photo: Amma Cat/Shutterstock
Q: I color my hair a dark auburn-red color that is quite attractive when the color is fresh and for a couple of weeks thereafter. When my brown and gray roots start becoming noticeable, however, it doesn't look quite as hot. Moreover, because red hair color tends to fade more noticeably than other hair colors, I almost always have to freshen up my overall color (by spreading the dye around to the ends for the last 10 minutes) when I touch-up my roots.
I wish I could color every 3-4 weeks, but I'm afraid to color my hair more often than every 5-6 weeks. Is coloring hair more frequently than that damaging? How often can you safely color your hair?
What can you do about roots in the meantime? Can you rotate a permanent with a non-permanent dye? Are there any good products you can use to temporarily color roots? I apply a tinted toner called "Stay Red" to visible roots after washing my hair, but it's hard to apply. I wish they had a mascara-type applicator.

A: Four to six weeks is typically the interval most hair salons will use to book color retouch appointments, and if you're using a deposit-only color formula, I don't see any reason to be too concerned about the frequency of hair color application. As for the technique of pulling through the color in order to freshen up the length of the hair, this is precisely what you should do when you do a retouch color service.
If the company that makes your permanent hair color also make a demi-permanent or semi-permanent color in the shade you use, you might try alternating between using the permanent and demi-permanent formulas.
Just be aware that since the demi-permanent color is designed to wash away in 6-12 shampoos, the longevity of the color will vary with your shampooing schedule. In addition, if your shampoo schedule is sufficient that the color lasts another 4-6 weeks, you'll see a larger new growth area at the scalp once your demi-permanent hair color begins to fade.
Stick to cover your gray hair roots
There actually are products for retouching hair color, such as you describe, available at your beauty supply store. They are typically next to the hair color products. However, these tend only to be found in the basest colors and shades, so you may not want to risk unpleasant results from using them.
See also:
Hair color application
How to touch up gray roots
How to make hair color last longer
The different types of hair color