The hair structure is composed of three parts: the cuticle, the cortex and the medulla (sometimes not found). The natural pigment of the color, called melanin, is found in the cortex of hair. The cortex is the thicker and most important part of the hair shaft and is protected by a transparent layer, the cuticle. The cuticle is formed by several overlapped layers which appears complete in virgin hair (not chemically treated) and of healthy appearance. On opaque hair, generally on length and ends, and in all chemically treated hair, the layers of the cuticle does not totally maintain the overlapping, resulting in increased porosity of hair. The factor of hair porosity is relevant to the results of coloring.

The natural color of the hair is determinate from the melanin, its production comes from the bulb an or hair follicle and depends from the genetic chromosomal information and physiology of the individual.

The color depends on two factors of the melanin

1. from the type of melanin:
   • eumelanin: granulose pigment with variable tones from red to deep black (found in higher percentage in darker hair)
   • feumelanin: diffused pigment with variable tones from yellow to light red (found in higher percentage in lighter hair)
2. from the quantity and its distribution, determining the degree and intensity of color.

Nature creates an infinity of colors; even if the human eye they could look the same, two natural colors are always different, and will react differently to the application of a cosmetic color. For this reason, the same color shade mixed with the same oxidizing strength will  not result the same on two different individuals.

Furthermore, hair natural color of an individual varies as time goes by, as the production and distribution of melanin may change, and consequently the natural color of hair darkens up to the appearance of gray hair. Even on the same subject the same mix of color can give a different output as the years goes by.

From the darker natural level to the lighter, the typology of melanin varies in percentage. For example, black natural color is determine by a thick presence of eumelanin granules; red natural color is determine by granules of feumelanin. Very light blonde is determine by the almost complete absence of melanin.

As the years goes by, the production of melanin normally slows down. The visible result is a gradual decrease in color of the single hair, till the total absence of melanin is reached. White hair is totally devoid.

The combination of natural melanin and cosmetic pigments (artificial) determine the final result after a color service.

When we decide to change the natural color of hair, using a cosmetic color, a direct color such as make over, or a semi-permanent color as Milk shake or a permanent color as z.one color the new attitude, the final result will be a consequence of the fusion with the natural pigment:

• a true combination of the lighten melanin with the artificial pigment applied (permanent color z.one color the new attitude)
• only an overlap of pigments (with milk shake and make over there isn’t a combination of pigments because they are not lifting colorings)

During the oxidizing process of a permanent color, the natural pigment of the hair is lifted, therefore the shades: red, golden red, gold, the base shades, will be predominant.

The final result of the coloring process is a combination of the cosmetic pigment and the natural pigment which derives from the oxidizing process.

Predominant pigments at each natural level (natural hair)