All of it boils right down to one thing I have never thought a lot about since highschool: chemistry. “There are numerous totally different chemistries that can be utilized to paint hair, and the classes overlap considerably,” explains beauty chemist Kelly Dobos. “Everlasting dyes contain the penetration of small colour molecules into the hair, that are then transformed into bigger molecules by way of a chemical response. These bigger molecules change into embedded within the hair.” In different phrases, they will not wash out.
Semi-permanent dyes, alternatively, “rely totally on dye diffusion into the hair cuticle,” says Dobos. “No chemical reactions concerned.” The dye molecules will not be embedded within the hair, which means {that a} semi-permanent dye will proceed to clean out with each wash.
Demipermanent dyes fall someplace in between. The magic (er, chemistry) is within the developer. “Builders assist open the hair cuticle, permitting dye molecules to penetrate,” says Dobos. Relying on the extent of developer you utilize, it might probably additionally “carry” or brighten the hair. “The quantity of carry is determined by the focus of peroxide within the developer,” she continues. “The upper the amount quantity, the larger the carry.” However a low stage developer reminiscent of a ten quantity “permits pigment to deposit with it No carry.”
Okay, chemistry class over. Demipermanent dye makes use of a gentle, low-volume peroxide developer (normally a 10-volume developer) to permit colour molecules to penetrate and coat the floor layer of the hair cuticle — and simply now the floor layer. Because of the low focus of peroxide, your hair will not change into lighter (excellent news, it will not harm it both). So it is not a good selection for those who’re hoping to go blonde, however it’s a terrific choice for mixing uneven colours, including lowlights, enhancing uninteresting or brassy blondes, or including richness and shine to any colour. That mentioned, if you have already got very darkish hair, you are positively restricted in what you are able to do with demi-permanent coloring. On this case, blondes have extra enjoyable.
The low-level developer provides the demi-permanent colour some endurance (semi-permanent dye is normally utilized with none developer), however a demi-permanent dye is barely anticipated to final about 24 washes earlier than that colour coating fades.
Advantages of utilizing demi-permanent hair colour
Colorist Rex Jimieson says demi-permanent colour has 5 key benefits over everlasting colour: “It would not comprise ammonia, it is simpler to develop out, it provides extra shine, it is simpler to alter later, and it units quicker.”
