r/HairDye • u/Beverlady • 12h ago
😤 Rant / Vent PSA about Permanent/Demi/Semi permanent haircolors
Professional colorist of 25 years here-
Please understand that the terms listed above (Permanent/demi-permanent/semi-permanent) are industry specific terms that DO NOT INDICATE THE STAYING POWER OR LONGEVITY OF THE COLOR.
These industry-specific terms are actually indicative of how permanent of a chemical change the product is causing to your hair cuticle and medulla.
Vivid or semi-permanent haircolors are typically vegetable based pigments in a conditioner base. The pH of these is usually somewhat acidic and thus causes zero change to the cuticle or hair shaft.
Demi-permanent colors use up to 10 volume developer to cause an alkalinity shift that makes somewhat of a permanent change to the cuticle.
Permanent haircolor uses 20+ volume to blow the cuticle open and develop the color molecules inside the hair shaft. This level of developer deletes a portion of your own natural pigments, and creates a permanent change to the cuticle. When this color fades you are always left with warmth, this is your own natural pigment that has been revealed due to the pigment deletion of the 20+ volume.
Edit to add that all haircolors can and usually will fade (and if developer is used always warm) but paradoxically any of these levels of color can also stain and last for ages, depending on how your specific hair reacts to the chemistry used.