Temporary

For individuals who wish to use a subtle neutralizer for yellowing hair or to neutralize unwanted tones. The pigment molecules in temporary hair color are large and, therefore, don't penetrate the cuticle layer, allowing only a coating action that may be removed by shampooing. An example of use of temporary hair color is for Halloween costumes.

Acid dyes are used to coat on the surface of hair, since acid dyes have a low affinity to hair, thus can be removed after a shampoo.

Semipermanent

Formulated to last through several shampoos, depending on the hairporosity and thus on its ability to absorb moisture. The pigment molecules are small enough to partially penetrate the hair shaft and stain the cuticle layer, or simply to change hair color into funky color for a day. Semipermanent hair color is mostly used by women to cover up any gray hairs that may have started appearing. In some cases, if the hair already has its own natural pigment (such as in younger people) the semipermanent hair color can act as permanent hair color, because you are applying another pigment on hair that already has pigment--graying hair lacks pigment. Generally speaking, semipermanent hair color acts like permanent hair color if using a dye a shade darker than the natural hair color. The product was made to be used by graying women or men to be matched to their natural hair color, or to go one to two shades lighter--a temporary fix. Follow instructions carefully.