Many people who have been dying their hair for years are suddenly stymied when their gray hair begins to resist the dye, and they have to figure out how to color resistant gray hair. Gray hair resists dye because it's coarser than normal hair and has a tighter cuticle layer than non-gray hair. However, there are several techniques you can try to color your resistant gray hair.

Go for Broke

If you've been using a semi-permanent dye or a natural vegetable dye and you're more than 40 percent gray, it's time to switch over to a permanent synthetic dye. Synthetic dyes contain hydrogen peroxide, which prepares the hair to allow the dye to set much deeper into the shaft.

Adjust Your Timing

If even synthetic permanent dyes have stopped covering your gray hairs completely, try adjusting the time you allow the dye to remain on your hair. If your gray hair is limited to certain areas, apply the dye to those areas first, wait 20 minutes, apply the dye to the rest of your hair, and then wait the amount of time specified on the dye box before rising out the dye. If you are more than 50 percent gray, apply the dye to your whole head at the same time, and then increase the amount of time you let it sit on your hair. If the box specifies 25 minutes, wait 45 before rinsing out your hair.

Make a Statement

If you hair resists the dye even when you leave it on for longer than the box specifies, it may be time to go up a shade or two. Stay with the same manufacturer and brand of dye that you've used in the past, simply darken the shade one or two levels.

Over-the-Counter Help

If your gray still resists the dye, it may be time to add a step to your process. You can add Ardell's Gray Magic to the dye you're currently using to help the color penetrate the cuticle and absorb into the shaft. If Gray Magic isn't available in your area you can try using a presoftener like 10-volume peroxide developer to help open the cuticle layer. Simply apply the presoftener to your gray areas for 10 to 15 minutes and then wipe it out of your hair using a clean dry cloth. Proceed to dye you hair normally.