Dyeing is a process designed to change the natural hair color, i.e. the composition of melanin molecules, which was given from birth.
There are several types of professional dyes.
FIRST GROUP - Bleaching (bleaching) products
Bleaching agents exist in the form of powder (soup), paste (cream) or oil. With this type of products, you can lighten both natural and previously colored hair up to 7-8 levels.
P"-environment: highly alkaline, and therefore this group of products has a very strong damaging effect on the hair.
There are two types of products:
- blond powders and pastes (based on persulphates). They work with both natural and previously colored hair.
- Cream-colors (high lift rows) - ammonia and/or its substitutes (ethanolamine, monoethanolamine). Only work with natural hair. Cream-color in itself is the 2nd group of dyes (i.e. permanent), but it is rows of high lift that many people refer to as the 1st group.
SECOND GROUP - permanent dyes
Persistent (permanent paints). In the process of staunch dyeing ammonia (or its substitute), which is a part of the dye, creates an alkaline environment, cuticle scales in this environment "open", and oxygen emitted by an oxidizer (oxide) brightens (oxidizes) the natural pigment of the hair.
Part of the oxygen released is used for clarification, while part of it "shows" artificial pigments in the dye. They polymerize, increasing many times, and are fixed in the inner cavities (cavities) of the hair.
Action on the hair: change the color by penetrating the dye molecule inside the hair. Natural melanin is partially oxidized and the result is a background of lightning.
P"-environment: alkaline.
Three GROUPs - Demi and seven-permanent (semi-permanent) dyes
Usually, they do not contain ammonia, but may contain ammonia derivatives (usually ethanolamine) to create a slightly alkaline pH. The paint works with the front layer of the cortex.
The difference between seven- and demi-permanent paints is that seven molecules are colored at once, but demi initially colorless and is manifested only in the process of dying.
FOURTH GROUP - Toning dyes
They work practically on the surface of the hair, without reacting with melanin, so there is no background of clarification. There is no ammonia or its derivatives in the composition. Soft "loosening" of the cuticle layer of hair occurs due to the presence of sulfates and additives in the composition of sulfates.
The dye mixes with the activator containing a weak solution of hydrogen peroxide (usually from 1.5% to 2%) which is necessary only for "to show" artificial pigments of a dye. The natural hair pigment is not lightened or destroyed, so such dyes do not lighten gray and do not lighten the hair.
PS-environment, as a rule, is slightly sour.
5 GROUP - Temporary (physical) dyes
Hair treatment: contains no ammonia or hydrogen peroxide. The action of this type of dyes is based on physical processes - the dye particles are kept due to the effect of adhesion (positively charged dye ions are attracted to negatively charged hair).
Direct (manifested) pigments settle on the surface of the hair.
There is also a subspecies of temporary dyes, which can be called plant dyes (henna, Basma, etc.).
They work by clogging the space between the hair cuticle scales with artificial pigments.
It is believed that dyes of this type are more careful to the hair than chemical dyes, but this is not quite so. Physical dyes actually leave the cuticle in the same condition as chemical dyes (including persistent ones).
The main damage of staining with resistant dyes (highly alkaline product) is caused by the alkaline environment, and not by oxide (acidic environment), which is designed to balance the alkali.
Alkali harms hair much more than acids: try to treat half of the hair with a weak solution of alkali, and the second half - with lemon juice and you will see clearly what half of the hair will have to be cut off.
Therefore, professional rule number 1 when dyeing - hair can be exposed to the effects of persistent (permanent) dye only once.
An alkaline environment is usually created by the action of ammonia. If you are promised to staunchly dye your hair without the use of ammonia, it is worth to treat the composition of such dye more carefully: usually instead of ammonia there contains monoethanolamine, which is obtained by the interaction of ammonia or aqueous solution of ammonia with ethylene oxide, which is even more harmful to the hair and more irritating to the scalp.
If you don't want to radically change your look or brighten your hair, you may want to have a semipermanent or shade color. They can give depth and shine to natural or previously colored hair without traumatizing the cuticle in the same way as persistent dyes do.