Originally Posted by helendy
Hair dye fading is a very common problem -- especially when a tintback
is performed. The color fades because the hair is porous. When the hair is porous, it can be difficult to get it to hold. If you go to a colorist, it will still fade.
One thing that most people don't think of is to dye it with a demi-permanent
dye. Demi-permanents are marketed as "semi-permanent" as the prefix "Demi" is poorly understood by the general population. One can tell the difference between a semi-permanent and a demi-permanent because the demi is mixed with a developer before you apply it. You can also look up the brand you're considering on the web
. Common demi-permanents include L'Oreal Castings Color Spa and Clairol Natural Instincts. There are some professional demi-permanents that you can get at Sally Beauty.
Now, I'm sure that a lot of people who are reading this will say "No Way!" and will consider giving me a reddie
. They will think, "how can something that's supposed to be temporary work?" Let me explain.
Demi-permanents work because they use large molecules. These molecules are not normally capable of penetrating the cuticle so they tend to deposit only on the outside of the hair. Washing tends to fade it away so it' becomes a long-lasting temporary dye. The developer (a weak hydrogen peroxide solution) is not strong enough to lighten the natural pigments (normally -- there are plenty of exceptions). Now, when you use it on very porous
hair, the demi is capable of penetrating the hair and depositing deep inside the hair shaft. If the hair weren't porous, it wouldn't work. Furthermore, because of the large molecular size compared to a "permanent" dye, it has a more difficult time leaching out of the hair than the normal dye.
You might also be able to increase its permanence by using a stronger peroxide solution (up to 20-volume) instead of the developer that it comes with (usually 6-volume to 10-volume peroxide), but that's probably an advanced technique. Also, doing that will actually cause less
pigment than normal to be deposited so it's may not help a great deal. If the peroxide strength gets too strong, it will deposit too fast and that will also cause problems, so you might be better off just using it from the box.