Hair and Scalp Analysis

Introduction to Hair Analysis

Hair and scalp analysis is the first mandatory step of any hairdressing service. It allows you to determine the natural state of the hair, its behaviour when exposed to chemical products, and to choose the appropriate techniques. This analysis is governed by the hygiene and safety standards of the Canadian Electrical Code, Part I (CE Code) (Rule 8-200 for electrical equipment used in salons) and the guidelines of CSA B149.1 for ventilation in spaces where chemical products are used.

The analysis is broken down into three complementary components:

Visual analysis: direct observation of the hair and scalp

Tactile analysis: palpation to assess texture and elasticity

Diagnostic analysis: specific tests (porosity, elasticity, compatibility)

> Golden rule for the exam: no chemical service (colouring, perm, relaxer) may be performed without a complete prior analysis. This rule is non-negotiable and is a classic trap in practical scenarios.

Hair Structure and Anatomy

The Three Layers of Hair

Hair is a keratinous structure composed of three concentric layers:

Layer	Location	Characteristics	Role
Cuticle	External	6 to 10 overlapping scales	Protection, shine, impermeability
Cortex	Intermediate	75-90% of the hair mass	Strength, elasticity, natural colour
Medulla	Central	Absent in fine hair	Thermal role, non-essential

The cuticle is the most important layer during chemical services. Its scales open under the effect of alkaline products (pH > 7) and close under the effect of acidic products (pH < 7). This property is fundamental to understanding how colouring and perms work.

The Hair Growth Cycle

Hair follows a three-phase life cycle:

16.Anagen phase (active growth): 2 to 7 years — 85-90% of hair is in this phase

17.Catagen phase (transition): 2 to 3 weeks — 1-2% of hair

18.Telogen phase (resting): 3 to 4 months — 10-15% of hair

Normal daily hair loss is 50 to 100 hairs per day. Beyond 100 hairs, hair loss is considered abnormal and requires a medical consultation.

> Essential calculation for the exam: to estimate the number of hairs on a head, use the average density of 150 to 200 hairs/cm². A full head contains approximately 100,000 to 150,000 hairs.

Hair Types and Classification

Classification by Diameter

Type	Diameter	Characteristics	Behaviour
Fine hair	< 60 μm	Soft, fragile, little volume	Reacts quickly to products, risk of over-lifting
Medium hair	60-80 μm	Balanced, resistant	Predictable reaction to products
Thick hair	> 80 μm	Coarse, resistant, voluminous	Reacts slowly, requires longer processing times

Classification by Shape

Straight hair: round cross-section, grows perpendicular to the scalp

Wavy hair: oval cross-section, grows at an oblique angle

Curly hair: elliptical cross-section, grows in a spiral

Very curly (coily) hair: flattened cross-section, grows in a zigzag, very fragile

Hair shape determines the amount of tension to apply during styling techniques and the choice of rods for a perm.

Classification by Condition

Condition	Visual Signs	Tactile Signs	Recommended Service
Healthy hair	Shine, highlights	Soft, elastic	All techniques
Dry hair	Dull, split ends	Rough, brittle	Hydration, nutrition
Oily hair	Greasy appearance, sticky	Smooth, heavy	Balancing, gentle shampoo
Damaged hair	White ends, breakage	Rough, porous	Trim, repair treatments
Coloured hair	Artificial highlights	Variable	Colour-protecting treatments

Scalp Analysis

Areas of Observation

Scalp examination must cover five distinct zones:

35.Frontal zone (hairline)

36.Parietal zone (crown of the head)

37.Temporal zone (temples)

38.Occipital zone (nape of the neck)

39.Peripheral zone (complete contour)

For each zone, assess:

Colour: pale pink (normal), red (inflammation), white (lack of vascularization)

Texture: supple, tight, scaly

Hydration: normal, dry, oily

Presence of lesions: sores, scabs, bumps, scars

Common Scalp Conditions

Condition	Symptoms	Cause	Contraindication
Dry dandruff	Fine white flakes	Dryness, desquamation	None, use anti-dandruff products
Oily dandruff	Yellowish, thick flakes	Hyperseborrhea	Avoid prolonged scalp massages
Seborrheic dermatitis	Redness, oily flakes	Fungus (Malassezia)	No chemical services
Psoriasis	Thick, silvery plaques	Auto-immune	No chemical services
Ringworm (tinea capitis)	Circular patches, broken hair	Contagious fungus	Refer to a doctor, refusal of service
Pediculosis (lice)	Nits, itching	Parasites	Refer to a doctor, refusal of service
Folliculitis	Small red bumps	Bacterial infection	Avoid the infected area

> Hygiene rule: any contagious condition (ringworm, lice, impetigo) requires a refusal of service and a referral to a healthcare professional. This rule is systematically assessed on the exam.

Diagnostic Tests

Porosity Test

Porosity measures the hair's ability to absorb and retain moisture. It is determined by the condition of the cuticle.

Procedure:

52.Take a clean, dry strand of hair

53.Hold the strand between the thumb and index finger of one hand

54.Slide the fingers of the other hand from the tip toward the root

55.Assess the resistance encountered

Result	Interpretation	Porosity	Implications
Easy sliding	Smooth cuticle	Low (2-3%)	Resistant hair, difficult to colour
Moderate resistance	Slightly open cuticle	Medium (5-8%)	Normal reaction to products
Strong resistance	Very open cuticle	High (10-15%)	Porous hair, absorbs too quickly, risk of over-processing

Complementary test: the float test — place a strand of hair in a glass of room-temperature water. Hair that floats has low porosity; hair that sinks quickly has high porosity.

Elasticity Test

Elasticity measures the hair's ability to stretch and return to its original shape. Healthy hair stretches 20 to 30% of its length without breaking.

Procedure:

61.Take a wet strand of hair

62.Gently stretch it between both hands

63.Observe the reaction

Reaction	Elasticity	Interpretation
Stretches 25-30% and returns	Normal	Healthy hair, can undergo chemical treatments
Stretches 10-20% and returns slowly	Low	Weakened hair, avoid aggressive treatments
Stretches more than 30% and does not return	Excessive	Over-processed hair, contraindication for perms
Breaks immediately	None	Very damaged hair, trim needed before any treatment

Compatibility Test (Strand Test)

The strand test is mandatory before any colouring or perm. It verifies the hair's reaction to the product and determines the exact processing time.

Procedure for colouring:

68.Prepare the mixture according to the manufacturer's instructions

69.Apply to a 2-3 cm² section behind the ear

70.Respect the planned processing time

71.Rinse and evaluate the result

Evaluation criteria:

Colour achieved: must match the expected shade

Hair condition: no breakage, no excessive lifting

Skin reaction: no redness, no itching

Skin Sensitivity Test (Patch Test)

This test must be performed 48 hours before any colouring containing oxidants or para-phenylenediamine (PPD) derivatives.

Procedure:

79.Clean a small area behind the ear or at the elbow crease

80.Apply a small amount of the mixture (colour + oxidant)

81.Cover with a bandage

82.Ask the client to return after 48 hours

83.Observe the reaction: redness, swelling, itching = positive reaction → absolute contraindication

> Exam trap: the sensitivity test must be performed with the complete mixture (colour + oxidant), not just with the pure colour. The strand test does not replace the sensitivity test.

Analysis of Grey and White Hair

Characteristics of Grey Hair

Grey hair results from the progressive decrease of melanin in the cortex. It has particular characteristics:

Variable porosity: often more porous than pigmented hair

Reduced strength: the keratinous structure is modified

Unpredictable reaction: white hair can absorb colour more quickly or more slowly depending on its porosity

Colour resistance: some white hair is resistant and requires pre-pigmentation

Percentage of White Hair and Colouring Strategy

Percentage of White Hair	Recommended Strategy
0-10%	Tone-on-tone colouring, highlights
10-30%	Demi-permanent colouring, tone-on-tone colouring
30-50%	Permanent colouring with 20-volume oxidant
50-70%	Permanent colouring with 30-volume oxidant, pre-pigmentation
70-100%	Permanent colouring with 30-40-volume oxidant, systematic pre-pigmentation

Pre-Pigmentation

Pre-pigmentation involves depositing base pigments on white hair before the final colouring. It ensures an even colour and prevents the "ghost colour" effect (white hair that stands out lighter).

Procedure:

97.Choose a pre-pigmentation shade: 1 tone lighter than the final colour

98.Apply only to the areas with white hair

99.Leave on for 10-15 minutes without rinsing

100.Apply the final colouring on top

Calculations and Measurements

Colouring Mix Ratios

Permanent colourings use a 1:1 ratio (one part colour to one part oxidant) or 1:1.5 (one part colour to 1.5 parts oxidant) depending on the brand.

Calculating the required quantity:

Hair Length	Quantity of Mixture
Short hair (5 cm)	30-40 g
Medium hair (15 cm)	60-80 g
Long hair (30 cm)	100-120 g
Very long hair (50 cm+)	150-200 g

Calculation formula: Quantity of colour = Total quantity ÷ (1 + oxidant ratio)

Example for 90 g of mixture at a 1:1 ratio:

Colour = 90 ÷ 2 = 45 g

Oxidant = 45 g

Calculating Processing Time

The processing time of a colouring depends on:

Hair porosity (prior test)

Percentage of white hair

Ambient temperature (a change of 5 °C modifies the time by 10%)

The type of oxidant used

General rule: processing time = manufacturer's base time × porosity factor

Porosity	Factor
Low	1.2 (increase time by 20%)
Medium	1.0 (standard time)
High	0.8 (reduce time by 20%)

Calculating Oxidant Dilution

Oxidants are available in volumes: 10, 20, 30, 40 volumes. To obtain an intermediate concentration:

Dilution formula: V₁ × C₁ = V₂ × C₂

Example: to obtain 60 ml of 25-volume oxidant from 30-volume oxidant and water:

V₁ × 30 = 60 × 25

V₁ = (60 × 25) ÷ 30 = 50 ml of 30-volume oxidant

Add 10 ml of water to complete

Safety Standards and Regulations

Ventilation and Air Quality

According to CSA B149.1, hair salons must maintain a minimum air exchange rate of 6 changes per hour in areas where chemical products are used. The maximum allowable concentrations for hairdressing products are:

Substance	Maximum Concentration (ppm)
Ammonia	25 ppm
Hydrogen peroxide	1 ppm
Formaldehyde	0.1 ppm
Toluene	20 ppm

Electrical Equipment

According to the Canadian Electrical Code, Part I (CE Code), Rule 8-200:

Dryers and electrical equipment must be grounded (three-prong plugs)

Electrical outlets must be installed at minimum 1 metre from water sources

Ground fault circuit interrupters (GFCI) are mandatory in wet areas

Equipment must be inspected annually by a qualified technician

Chemical Product Management

Products must be stored in their original containers with the label intact

Safety Data Sheets (SDS) must be accessible at all times

Expired products must be disposed of according to the manufacturer's instructions

Nitrile gloves are mandatory for all handling of chemical products

Complete Analysis Procedure

Step 1: Consultation and Client History

142.Welcome the client and make them comfortable

143.Ask questions about:

Previous chemical treatments (date, type, products)

Known allergies

Current medications

Hair care habits (shampooing, brushing, heat tools)

Goals for the visit

149.Record the answers in the client file

Step 2: Visual Observation

151.Examine the scalp zone by zone (5 zones)

152.Observe hair distribution (density, areas of thinning)

153.Assess shine, natural colour, highlights

154.Identify any abnormalities (lice, lesions, redness)

Step 3: Tactile Analysis

156.Palpate the scalp to assess mobility and texture

157.Take hair samples from different zones (frontal, occipital, temples)

158.Perform the porosity test on each sample

159.Perform the elasticity test on wet hair

Step 4: Complementary Tests

161.Skin sensitivity test (if colouring is planned) — 48 hours before

162.Strand test (if colouring or perm is planned)

163.Complementary porosity test (float test)

Step 5: Diagnosis and Recommendations

165.Summarize the results in an analysis chart

166.Identify any contraindications

167.Propose appropriate techniques

168.Explain the results and recommendations to the client

169.Document in the client file (mandatory for traceability)

Summary Table of Contraindications

Condition	Colouring	Perm	Relaxer	Trim
Healthy scalp	✓	✓	✓	✓
Seborrheic dermatitis	✗	✗	✗	✓
Active psoriasis	✗	✗	✗	✓ (with caution)
Ringworm	✗	✗	✗	✗ (refer)
Lice	✗	✗	✗	✗ (refer)
Open sores	✗	✗	✗	✓ (avoid the area)
Very porous hair	✓ (reduced time)	✗	✗	✓
Brittle hair	✗	✗	✗	✓ (trim recommended)
Pregnancy	✓ (with caution)	✓	✓	✓
Known allergy	✗	✓	✓	✓

Summary

Hair and scalp analysis is a fundamental skill systematically assessed on the Red Seal exam. The essential points to remember:

174.Analysis is mandatory before any service, without exception

175.The three diagnostic tests (porosity, elasticity, compatibility) are complementary and not interchangeable

176.The skin sensitivity test must be performed 48 hours before any colouring with PPD

177.Contagious conditions (ringworm, lice) require a refusal of service and a medical referral

178.Measurement calculations (1:1 ratio, oxidant dilution, processing time) must be mastered

179.Documentation of the analysis in the client file is mandatory for traceability

180.Safety standards (CSA B149.1, Canadian Electrical Code, Part I) govern the use of products and equipment

Pitfalls to Avoid

Confusing the strand test and the sensitivity test: the strand test assesses the hair's reaction, the sensitivity test assesses the skin's reaction. Both are necessary.

Neglecting the porosity test on white hair: white hair has variable porosity that directly influences the colouring result.

Forgetting the temperature factor: an increase of 5 °C reduces processing time by 10%. A salon that is too warm can cause over-lifting.

Using an oxidant that is too strong: a 40-volume oxidant on porous hair can cause irreversible breakage. Always adapt the oxidant to the porosity.

Ignoring signs of allergic reaction: any redness, itching, or swelling during the sensitivity test is an absolute contraindication.

Not documenting the analysis: the absence of a client file is a violation of traceability standards and can lead to penalties.

Confusing white hair percentages: 30% white hair does not require the same strategy as 70%. Pre-pigmentation is mandatory above 50%.

Forgetting the elasticity test on wet hair: the test must be performed on wet hair, never on dry hair, to obtain a reliable result.

Using expired products: oxidants lose their effectiveness over time. Always check expiration dates.

Not checking ventilation: a salon without ventilation compliant with CSA B149.1 exposes the stylist and clients to dangerous concentrations of chemical vapours.

Hair and Scalp Analysis