Question about Demi-Permanent Haircolor

It`s probably not your imagination.

Permanent haircolor works by prying open the hair`s cuticle so undeveloped dye molecules can float inside. Once inside, they bump into other undeveloped dye molecules and tend to cling, forming long chains of dye molecules that stay there permanently (until the hair they`re in grows out) because, basically, the chains of dye molecules are too big to fit through the openings they came in through. Kind of like if you carried individual boards into a room, built a huge entertainment center from them, then later discovered that the finished entertainment center itself was too big to fit through the door.

Demi-permanent haircolor is based upon the same general idea as permanent (hence the name) -- dye molecules bump into one another, cling, and form long chains. The difference is that no/little ammonia is used, so the hair doesn`t "open up" enough to let the undeveloped dye molecules float inside (at least, not very far). Instead, some of the molecules get wedged into the openings, then more dye molecules bump into them, stick together, and form chains of dye molecules. Along the way, long chains of molecules might wrap around the hair shaft, or multiple wedged-in dye molecules might be joined by more chains.

I think you can see the key difference: with permanent haircolor, the dye is almost entirely inside the hair. When acidic conditioner is used, the openings pried open by the ammonia get closed up and smoothed out even more. With demi-permanent haircolor, the bulk of the dye molecules are actually hanging off the outside of the hair. The roughness you feel is the dye, and the flatness/residue comes from the irregular surface of the hair (smooth = shiny; rough = matte).

This is also why demi-permanent fades a lot more than permanent. Over time, abrasion and scrubbing breaks off some of the dangling polymer chains. Not all of them (some ARE quite firmly wedged into the outer layers of the hair), but definitely some of them.

Demi is usually used on bleached hair in preference to permanent because bleached hair has ALREADY been "pried open". On bleached hair, demi can act quite a bit like permanent because the color molecules can get deeper into the hair than they would in unbleached hair. Often, demi lasts longer on bleached hair than permanent because the polymer chains created by permanent are usually smaller than the chains created by demi (the dye molecules themselves are smaller). Since bleached hair has been damaged and usually can`t be "closed up" very tightly afterward, even with intensive treatment using acidic conditioner, the smaller permanent dye molecules can literally "fall through the cracks" and wash out over time.

You can mention your concerns to your stylist, but in all likelihood there`s not a whole lot he/she can do until the bleached hair grows out and gets cut off. Permanent color might avoid the roughness and produce shinier results, but it might not last very long before requiring pigmented shampoo or re-application.

Pigmented shampoo will put you back to square one. It`s kind of an extreme case of demi... already-polymerized chains of dye molecules that basically get tangled around the exterior of the hair and last a few days before washing away. The same complaints you`re having about roughness and dullness will probably accompany the shampoo, since it`s the same basic result (chains of dye hanging from the hair).

Repeatedly applying permanent will give diminishing results. Each time it`s applied, the damaged openings won`t close up as tightly as they did before, so it will become easier and easier for the dye inside to fall out and wash away.

In all honesty, demi is probably your best option.