There are many types of color applications you can choose from when you go to a salon, Here they are:
PERMANENT COLOUR
Permanent hair color contains ammonia. These colors must be mixed with a developer or oxidizing agent in order to permanently change hair color. Ammonia in color is used to open the cuticle layer so that the developer and color molecules together penetrate into the cortex. The developer or oxidizing agent, comes in various volumes. The higher the developer volume, the higher the lift will be of a person’s natural hair pigment. Someone with dark hair wishing to achieve two or three shades lighter may need a higher developer. Whereas someone with lighter hair wishing to achieve darker hair will not need a high developer. Timing may vary with permanent hair coloring, but is typically 30 minutes or 45 minutes for those wishing to achieve maximum gray coverage.
- Permanent colors changes hair structure to make colors change
- Will cover grey completely
- Provides Full hair color coverage
- Lasts up to 8 week
DEMI-PERMANENT COLOUR
Demi-permanents have several advantages as compared with permanent color. Because there is essentially no lifting (i.e., removal) of natural hair color, the final color is less uniform/homogeneous than a permanent and therefore more natural looking. They are gentler on hair and therefore safer especially for damaged hair. They wash out over time (typically 20 to 28 shampoos) so root regrowth is less noticeable. Demi-permanent hair colors are not permanent but the darker shades in particular may persist longer.
SEMI-PERMANENT COLOUR
The final color of each strand of hair will depend on its original color and porosity, so there will be subtle variations in shade across the whole head. This gives a more natural result than the solid, all over color of a permanent color. However, it also means that gray or white hairs will not appear as the same shade as the rest of the hair. If there are only a few grey/white hairs, the effect will usually be enough for them to blend in. Semi-permanent color cannot lighten the hair.
- used as a hair gloss to create shine
- Clear used to add shine
- Lasts up to 8 shampoos
ALTERNATIVE COLOUR
The chemical formulae of alternative color dyes typically contain only tint and have no developer. People with darker hair (medium brown to black) need to use a bleaching kit before tint application. Some people with fair hair may benefit from prior bleaching as well. Unwanted tones in hair that have not been lightened enough can adversely affect results, especially with pinks, blues and greens. Some alternative colors are semi-permanent, such as blue and purple, it could take several months to fully wash the color from bleached or pre-lightened hair.
Some of this text was not written by myself. Here are the links to my sources:
https://en.m.wikipedia.org/wiki/Hair_coloring
https://www.madison-reed.com/blog/semi-and-permanent-color