I was reading an interesting article about hair dye colors in hair scientist and thought I would relay it here.
The first recorded references to hair dye colors relate to Henna obtained from the Egyptian privet.
Simple Hair dyes have historically been manufactured by the infusion of natural vegetation.
Other categories possess increasingly complex chemicals.
Modern Hair dyes can produce wonderful results, but some involve sophisticated chemicals which are capable of inducing hair damage.
Hair dyes may be classified as:
Vegetable hair dye colors: If pure are extracted from plants. Most vegetable dyes will wash out of the hair. Henna however is a 'permanent hair dye color', which may change the feel and lustre of hair.
Pure Vegetable hair dye colors are basically harmless and do not require allergy tests. It is unlikely that any adverse skin reaction or hairshaft damage would result from their use. Egyptian (Vegetable) Henna however can, in some people, make the hairshafts seem dry and lustreless. This is not injurious. This form of henna is used in some shampoos e.g. to provide auburn highlights.
Camomile is another of the vegetable hair dye colors, it coats the hairshaft adding a yellowish hue.
Some 'vegetable' hair dye colors may contain permanent oxidation dye ingredients, as an example, Tunisian Henna where available is not a vegetable dye as it contains metallic salts and is classed as an inorganic dye.
Inorganic hair dye colors: include hair color restorers, sulphide and reduction dyes based on metallic salts. These dyes produce permanent colour changes.
Synthetic organic hair dye colors are based on coal tar products. they include:
1) Temporary hair dye colors These dyes will wash out of hair.
2) Semi-permanent hair dye colors These dyes produce red yellow and blue colourings. These dyes wash out of hair after 6-8 shampoos.
3) Permanent oxidation hair dye colors They require an oxidising agent e.g. hydrogen peroxide to function.
Colours may fade with strong sunlight.
The process may change the feel of hair.
4) Quasi-permanent hair dye colors are a mixture of semi-permanent and permanent oxidation dyes. The semi-permanent ingredient will wash out.
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