In my previous article we discussed progressive hair coloring which uses heavy metals such as lead to create color pigments on hair. We’ve discussed about the benefits and problems of using these pigments. The term progressive is usual associated with those metallic dyes systems. So instead we will use the general term of gradual hair coloring for systems that don’t require any metals.
What is gradual hair coloring?
In gradual hair coloring, the hair dyes do not deposit uniformly on every single hair fiber in one application. It provides a more natural transition for those who want to partially cover some gray. After additional applications, more color deposits, replacing those dyes that have washed out and adding dyes to the virgin fibers. The frequency of the applications will determine the extent of coverage and the depth of the shade. It thus allows a certain level of control for those who don’t want an instant make over.
What’s the technology behind?
An example of one such coloring system is the popular Just for Men: Touch of Gray. The ingredients are listed below:
The hair coloring process is a 5 min application with no mixing required. The technology uses aminomethyl propanol (AMP) which is a base and provides a high pH environment for hair. This allows the hair to swell and the cuticles to open. The dye precursors (highlighed in blue) are the same ones used in permanent hair coloring. Note the presence of the popular p-Phenylenediamine (PPD) and p-Aminophenol.
The dyes precursors which are small uncolored molecules will enter the hair easily. This system doesn’t use any hydrogen peroxide to oxidize the dye precursors. Instead, it relies on the oxygen of the air. This slow oxidation is what causes the large dye pigments to form gradually into the hair fibers.
And because of this slow oxidation, the efficiency of the gray coverage lower than permanent hair coloring, thus achieving the intended effect of partial gray.
Another brand using this same technology is Wella SP Gradual Tone.
Advantages of gradual hair coloring
- Control over color shade over multiple applications
- Smoother transition from gray
- No ammonia or peroxide = less internal damage to hair fiber
- Formed color will last for a couple of weeks
- No risk of heavy metal poisoning
- PPD is a known strong allergen. It shouldn’t be used if you are sensitive to this chemical.
- Other hair dye precursors present such as p-Aminophenol can also cause irritations and redness.
- The hair will suffer some level of damage from the use of aminomethyl propanol or methylethanol amine that causes a high pH environment. A low pH shampoo/conditioner is required after.