HAIR DIAGNOSTIC

HAIR DIAGNOSTIC

The consultation is key to a successful hair colouring procedure and a strict formula of hair diagnostics should be followed prior to every colour application. The first step is an understanding of the three distinctive layers of the hairs structure.

Describe each of the following:

The Cuticle

The Cortex

The Medulla

Why is it so important to discover the clients hair history?

A visual assessment will determine what?

Why is it important to ask open ended questions?

The protective outer layer is formed of overlapping layers of translucent scales through which the

colour pigment can be seen clearly. The scales hinge outwards to allow chemical treatments to penetrate

The cortex is the middle layer of hair and forms its main bulk. It contains the hairs natural

pigment. The long cable like fibres hold the natural moisture and protein, giving strength and pliability.

The innermost layer of the hair which is comprised of soft spongy matter which serves no

purpose and is not always present in hair with finer density.

HAIR HISTORY

It is essential to ascertain the hair history as this could

dramatically alter the result of the chosen shade and technique.

If the hair is in a natural state , or has been previously coloured.

Regarding previous chemical services will give a more

detailed background to the number and type of treatments previously applied to the hair.

HAIR DENSITY

What does hair density refer to?

What will density have an effect on?

Give an example

Describe the following types of density:

Fine

Normal

Coarse For the colouring process, hair density refers to how fine or course the

individual hair strands are.

The technique and type of colour product employed.

Very fine hair may not able to withstand harsh chemical and may suffer breakage. Very

thick or course hair may need stronger tone and peroxide or oxidant for the colouring process.

Fine hair is typically referred to as having a diameter of 50/60 micrometers.

Normal hair 70/80 micrometers.

Course hair is classified as above 80 micrometers.

FINE NORMAL COARSE

POROSITY

Define porosity: The hair’s ability to absorb liquid (which determines the application and development time

of colour) is referred to as porosity.

If the hair is more porous, the more Absorbent

it is.

Will previously treated hair be more or less porous? Previously treated hair maybe highly porous.

How will porous hair respond to colour products and development time? Porous hair will respond to colour products

more quickly, so development time may be shorter than normal.

What kind of application is usually needed on porous hair? When working on porous hair, it may be necessary to

apply the chosen shade at the roots first, as these will be less porous.

Where should the product be applied to first on overly porous hair? On the ends of the hair later in the technique.

RESISTANT AND PREVIOUSLY UNTREATED HAIR

How does thick hair differ from porous hair? Thick hair absorbs minimal moisture and liquid.

Previously untreated or resistant hair absorbs minimal moisture & liquid, would development time be faster or slower?

Development time may be slower than normal.

How is the cuticle different and how does that affect colour application? Hair that is less porous will have a tighter

cuticle layer, more colour may need to be applied and development time extended.

SCALP CHECK

Prior to commencing any colour technique what is it advisable to do?

When the colour product is in contact with the scalp, what advice should be given to the client regarding shampooing?

And why?

When should a skin test be given?

Explain the skin test procedure? Conduct a through hair and scalp diagnostic,

checking for any cuts, abrasions or other irregularities that may affect the colouring process.

It is advisable not to shampoo for 24 hours prior to application.

The skins sebaceous oils will offer protection.

SKIN TEST

Skin test should be given for all colour techniques that involve colour

product coming into direct contact with the skin, and should take place well before the service.

The standard method is to apply a small amount of the chosen shade /

peroxide or oxidant behind the ear and left uncovered for at least 48 hours. Please refer to the

manufacturer’s instructions.

INCOMPATIBILITY TEST

What is the purpose of this test? This is a test whether any chemical product already on the hair will react

unfavourable with the intended colour procedure.

How is this test carried out? Take a small clipping from the hair underneath the occipital bone and place it in

a solution of peroxide or oxidant.

PRE-COLOURING TEST

What is the purpose of this test?

the intended colour. This test indicates how hair that has been chemically treated will respond to

How is this test conducted? Take a small section of hair from underneath the occipital bone and apply the

intended shade, peroxide or oxidant and assess the result before proceeding.

ELASTICITY TEST

What is elasticity?

This test is a way to assess what?

How would hair in good condition react?

How would hair in poor condition react?

How would an elasticity test be conducted?

Elasticity describes the ability of the hair to stretch and return to its original shape.

the cortex. The elasticity test is a way of assessing the degree of potential damage to

and return. Hair in good condition can stretch up to a third of its original length

Hair in poor condition lacks the ability to bounce back into shape. Poor

elasticity is always accompanied by a porous, damaged cuticle and hair which has a tendency to break.

Take a strand of hair and hold with the forefinger and thumb. Gently

pull and see how much the hair stretches and how quickly it returns to its original shape.

PERCENTAGE OF WHITE HAIR

When covering white hair it is imperative to judge the percentage of white hair present. In most colour ranges there is a guide detailing how much natural base tone needs to be added to achieve the target shade.

When covering grey what base tone needs to be added to achieve the target shade?

What effect will too little natural base give?

Give an example:

0% - 25% white hair?

25% - 50% white hair?

50% - 75% white hair?

75% - 100% white hair? In most colouring product ranges,

there will be a guide detailing how much natural base tone needs to be added to achieve the target shade.

Too little natural base in the formula will result in the white hair

having a translucent tone in comparison to the naturally pigmented hair.

tone. If the targeted shade is red on a natural brown base, the white hair will have bright pink

WHAT ARE THE SASSOON GUIDELINES FOR THIS?

No base tone needed to be added.

25 % of the formula needs to be the base tone of the target shade.

50 % of the formula needs to be the base tone of the target shade.

75 % of the formula needs to be the base tone of the target shade.