Is it okay to dye black hair and then yellow hair?

No, you can't dye your hair yellow directly after it is dyed black. As the case may be, it can only be dyed after bleaching.

At present, there are three kinds of common hair dyes on the market:

Oxidized permanent dye paste

wax printing

Metal hair dye

Oxidation permanent dye paste dyeing is to use the artificial pigment in the dye paste to combine with the natural pigment of hair to develop color. Dyeing black is the primary color used, which contains a lot of blue pigment and red pigment. These pigments are different from natural pigments in hair and are artificial pigments, which cannot be lightened. Therefore, there is a common sense in dyeing hair. Artificial pigments cannot be lightened, but only lightened. Even using 0/00 brightening cream can only make the hair look less black, but it is not obvious. If you must dye it yellow again, you can only bleach your hair with bleach or bleach paste, and then dye it when it turns yellow, otherwise it will be affected by the red background color. And even if it is bleached and dyed, the hair quality will be very poor, and then it will be very dry for half a month at most, because bleaching powder will destroy the hair scales on the hair surface.

Batik is currently called waxing. The principle is to wrap the hair surface with dye, and the strength of the dye is not enough to cover the color. Black wax is uncommon. If it is acidic wax, it can be washed with wax-washing paste before dyeing, but this is unlikely. After all, almost no one dyes black with acid batik.

Metal hair dye, also known as metal wax, contains metal components, the principle is the same as above, but it has strong covering and durability, contains heavy metal components, and may cause cancer. If you wax black hair with metal, it is almost impossible to change the color. Even with bleaching powder, it may not be washed out. The worst thing may be that the fading will be red or pink, and the hair is almost cotton, so it is impossible to fade. The best way is to wait until the dyed hair grows, then trim it and dye it.

Conclusion: It is suggested to find a professional barber shop and communicate with the hair stylist to avoid unpleasant things.