Henna is a natural hair dye based on the lawsonia plant. It gives hair, depending on the initial condition and color, shades from bright red to dark copper. Henna not only colors, but also strengthens the hair, makes it denser, thicker and stronger. But she has one drawback - after using henna, the hair cannot be dyed with artificial dyes. The result can be unpredictable, and in the best case, the dye simply will not fall on the hair.
How henna and artificial colors dyes hair
Henna is a cloudy, swampy powder with a specific odor. Lavsonia leaves contain molecules of tannin, a natural orange dye, but this pigment is not visible in the powder, as it is overshadowed by chlorophyll. But if you grind the leaves and dilute them in water, or even better in an acidic liquid, for example, lemon juice, then the cell membranes will dissolve, the dye is released.
If at the same time henna is applied to the hair, then the released dye begins to flow into the hair shaft, where it combines with keratin. Thus, henna penetrates directly into the hair structure, tannin molecules bind tightly to keratin on the outer layers of the hair. Therefore, henna is almost not washed off from the strand - the paint darkens a little over time, but it adheres tightly, it is extremely difficult to wash it.
It is due to its ability to penetrate the hair structure and bind to keratin that henna strengthens the hair, makes it thicker and stronger.
Chemical dyes without hydrogen peroxide envelop the hair, giving it the desired color. Dye with peroxide in the composition releases oxygen at the time of dyeing, which penetrates into the hair pigments and lightens them.
If the hair is natural or dyed with an artificial dye, then the dye behaves predictably, but it does not combine well with plant pigments: the dye either does not appear, since it cannot fight such a strong pigment, or under the influence of tannin it changes its action, leading to the creation of another color, or has a weak effect and dyes the hair unevenly. At the same time, it is difficult to predict in advance what kind of effect will be obtained if you use paint after henna.
Chemical paint after henna
When henna plant pigment and chemical dye interact, different results can be obtained, usually disappointing. In some cases, the hair takes on unexpected shades - from bright orange to green. The risk of getting a green color on your hair increases if you added basma for a darker and more saturated color during the previous henna dyeing. Even if the color in general turned out to be good, then in daylight you can notice the greenish reflections of the hair.
In other cases, chemical paint does not adhere well to henna and has almost no effect. Many girls also complain that even when they managed to paint over the henna with fake paint, the copper tint still made itself felt. It is not always possible to repaint in order to remove greens or reddishness. However, it cannot be said that paint always leads to unpleasant consequences after henna.
Sometimes you can get lucky, and the expected effect of the dye will coincide with the result, it all depends on the structure of the hair, the quality of the dye, the henna used and other factors.
But since the dye behaves unpredictably, lying on henna, most hairdressers do not undertake to dye such hair and do not advise doing it yourself. If you don't want to wait for your hair to grow back to dye it, be sure to first test a small lock in the middle of your hair to check the effect of a particular dye on the henna.