05 marzo 2013

Hair Colouring

Ecco a voi il primo post in lingua inglese pubblicato su Science for passion.
L'idea di mescolare le lezioni frontali ed il blog è piaciuta molto sia ai colleghi sia agli studenti.
La professoressa Ornella Marelli ha deciso di utilizzare questa opportunità per avvicinare le ragazze di quarta allo studio dell'inglese.
Oggi parliamo di colorazione per capelli con un lavoro realizzato da Tania Melnik della classe IV benessere.
A me sembra davvero un ottimo lavoro: semplice e chiaro, con tanto di fotografia originale! Che ne dite?
Non mi resta che augurarvi buona lettura.
Tania Tanfoglio

Hair Coloring di Tania Melnik

Hair Colouring is the process of adding colour to the natural hair colour. It is used to disguise or cover over white hair, or to enhance and change the natural hair colour.

Tetiana is trying a new colour

The natural pigments of hair are found in the cortex; outermost layer of the hair-shaft- the cuticle-that covers and protects the cortex, is translucent, therefore it allows us to see through  the hair’s natural colour. Eumelanin is the black and brown pigment, while phaeomelanin is the pigment responsible for blond and red.

Product Available to Dye Hair
Temporary colour: this type of colour is found mainly in sprays, gels, water  rinses and some colour shampoos. This colour contains large colour molecules which are too large to penetrate the cuticle layer of the hair, and it doesn't contain ammonia, which is used to open the hair cuticles, allowing the colour molecules to penetrate inside the hair. This type of colour will only last one wash.

Semi –permanent colour: this type of colour will last between six to eight  washes, depending  on the natural hair colour and the tone of the colour used. With eight shampoos  the colour will fade. This type of colour contains a mixture of sizes of coloured molecules, and as it is slightly alkaline the cuticle scales will open, thus allowing the product to enter the cuticle: the smaller the molecules, the farther they will travel. So as the hair is shampooed each time, the large molecules will wash out but the smaller molecules will remain, enabling the colour to last longer.

Permanent colours: these tints, also called oxidation dyes, require the addition of hydrogen peroxide, otherwise they will not work. The small colourless molecules within the tint enter the cortex. Once inside, the hydrogen peroxide activates them into joining together to form large coloured molecules which then become trapped within the cortex. This process can take anything from thirty minutes to sixty minutes, depending on the product that you are using. If this product is taken off too soon, it will become semi-permanent.

Ed ecco la versione originale e scaricabile:


Grazie a tutti i lettori… :-)
Tania Melnik

Nessun commento:

Posta un commento

Related posts

Related Posts Plugin for WordPress, Blogger...