4.2 Hair & Scalp Analysis (Texture, Density, Porosity, Elasticity)
Key Takeaways
- Four factors drive hair analysis: texture (strand fineness/coarseness), density (hairs per area), porosity (moisture absorption), and elasticity (stretch and return)
- Porosity is tested by sliding fingers up a dry strand against the cuticle — smooth means low porosity (closed cuticle), catching means high porosity (raised cuticle)
- Elasticity is tested on a wet strand; low elasticity warns of breakage risk and means chemical or thermal services should not proceed
- Scalp analysis identifies dry, oily, dandruff, or normal conditions and influences product and service selection
- No chemical or thermal service should proceed without a full hair and scalp analysis
The Four Pillars of Hair & Scalp Analysis
Quick Answer: Before every chemical or thermal service, analyze four hair factors — texture (strand fineness), density (hairs per area), porosity (moisture absorption), and elasticity (stretch and return) — plus the scalp condition. Together they determine whether a service is safe and which products to use.
No two heads of hair are the same. A thorough analysis protects the client, prevents unfavourable reactions, and produces results that last. The Red Seal exam expects you to know each factor, how to test it, and how to interpret the result.
1. Texture
Texture refers to the fineness or coarseness of an individual hair strand — not how the hair looks overall, but how a single strand feels. Texture is determined by the diameter of the hair shaft and is categorized as:
| Texture | Feel | Behavior |
|---|---|---|
| Fine | Smooth, barely felt between fingers | Processes quickly; susceptible to damage; may not hold volume |
| Medium | Felt but not wiry | Most common; processes at a normal rate |
| Coarse | Thick, wiry, clearly felt | Processes slowly; resistant to chemical services; holds shape well |
Texture cannot be changed by products — it is a structural feature of the follicle. Service timing and chemical strength must be adjusted to match the texture.
2. Density
Density is the number of hair strands per square inch (or square centimeter) of scalp. It is independent of texture — fine hair can be dense, and coarse hair can be sparse.
| Density | Description |
|---|---|
| Sparse (low) | Scalp easily visible through the hair |
| Medium | Scalp visible only when hair is moved |
| Dense (high) | Scalp barely visible even when hair is parted |
Density influences product quantity, section size during services, and the visual fullness of a finished style.
3. Porosity
Porosity is the hair's ability to absorb moisture — a direct measure of cuticle condition. It is the single most important factor for predicting how a chemical service will perform.
| Porosity | Cuticle State | Strand Test Result | Implication |
|---|---|---|---|
| Low | Tight, flat, closed | Strand feels smooth when fingers slide up the shaft | Resistant to moisture and chemicals; needs longer processing or higher pH to lift cuticle |
| Normal | Healthy, slightly raised | Slight resistance when sliding up | Accepts moisture and services evenly |
| High | Raised, damaged, porous | Strand catches or feels rough sliding up | Absorbs moisture fast but releases it fast; processes very quickly; high breakage risk |
The strand test: Take a single dry strand between thumb and index finger. Slide your fingers from the tip toward the scalp (against the cuticle direction). Smooth = low porosity; catching or rough = high porosity.
High-porosity hair has usually been damaged by previous chemical services, heat, or environmental exposure. It may need protein treatments to rebuild structure before any further chemical work.
4. Elasticity
Elasticity is the hair's ability to stretch and return to its original length without breaking. It is a direct measure of cortex health, because the cortex provides the hair's strength and spring.
The wet strand test: Take a single wet hair, hold it firmly at both ends, and stretch gently.
| Elasticity | Behavior | Service Implication |
|---|---|---|
| Normal (high) | Stretches up to 50% of its length and returns | Safe for chemical services |
| Low | Stretches little or breaks; does not return | Do NOT perform chemical or strong thermal services — breakage likely |
Low elasticity usually signals that the cortex has been weakened by previous over-processing, chemical damage, or protein deficiency. A protein treatment may rebuild elasticity, but the client should be referred to avoid further damage until condition improves.
Scalp Analysis
Alongside the hair, the scalp must be examined before any service. Common scalp conditions:
| Condition | Signs | Service Implication |
|---|---|---|
| Dry scalp | Flaky, tight, powdery white flakes | Use moisturizing products; avoid hot water; gentle scalp treatments |
| Oily scalp | Shiny, greasy roots, yellowish sebum | Use balancing/clarifying shampoo; avoid heavy conditioners at the roots |
| Dandruff | Visible flaking, may be oily or dry | Use appropriate medicated or balancing shampoo; do not abrade the scalp |
| Normal scalp | Balanced, no excess oil or flakes | Standard service |
If a scalp shows signs of a contagious condition or an open sore, the service must be stopped or refused and the client referred to a physician (see Section 4.3).
Why Analysis Matters Before Every Chemical Service
A chemical service performed on unanalyzed hair is the leading cause of unfavourable reactions: breakage, scalp burns, uneven color, and allergic responses. Always perform analysis to:
- Confirm the hair and scalp are healthy enough for the planned service
- Choose the correct product strength and processing time
- Identify when to refuse or defer a service and refer the client
This is a non-negotiable step on the Red Seal exam and in practice.
When performing the porosity strand test, what does it mean when your fingers catch or feel rough sliding up a dry strand toward the scalp?
Which analysis factor is described as the number of hair strands per square inch of scalp?
A wet strand stretches only a tiny amount and breaks when pulled gently. What does this indicate, and what is the correct service decision?