2.2 Hair Analysis, Porosity, and Elasticity

2.2 Hair Analysis, Porosity, and Elasticity

Introduction to Hair Analysis

Before a cosmetologist performs any service—whether it is a simple haircut, a complex hair color formulation, or a chemical texturizing service—a thorough hair and scalp analysis must be conducted. This analysis is not just a recommendation; in Florida, it is a professional safety standard. By evaluating the hair’s texture, density, porosity, and elasticity, you can determine what products to use, how long they should process, and whether the hair can safely withstand the service.

The Four Essential Factors of Hair Analysis

The four key factors that dictate how hair behaves and responds to products are:

1. Texture
2. Density
3. Porosity
4. Elasticity

1. Hair Texture

Hair texture refers to the thickness or diameter of the individual hair strand. It is classified into three categories:

• Coarse Hair: Has the largest diameter. It contains more cortex cells and often has a well-defined medulla. Coarse hair is highly resistant to chemical services, meaning it requires stronger solutions and longer processing times to raise the cuticle and penetrate the cortex.
• Medium Hair: The most common hair texture. It is considered the standard or norm to which other textures are compared. Medium hair processes normally and presents no special difficulties during services.
• Fine Hair: Has the smallest diameter and is the most fragile. It is easy to damage and processes much faster than coarse or medium hair. Fine hair has a thin cuticle and may lack a medulla, making it highly sensitive to chemical treatments.

How to test: Hold a single strand of dry hair between your thumb and forefinger, and slide your fingers down the strand. Coarse hair will feel thick and distinct, medium hair will feel normal, and fine hair will feel thin, smooth, and barely perceptible.

2. Hair Density

Hair density is the number of individual hair strands on one square inch of the scalp. It indicates how thick or thin the client's hair is as a whole, which determines the amount of product and time needed for a service.

• Low Density (Thin): Sparse hair distribution.
• Medium Density: Average hair distribution.
• High Density (Thick): Dense hair distribution.

The average hair density is approximately 2,200 hairs per square inch. The total number of hairs on a human head varies by natural hair color:

• Blonde: ~140,000 hairs (highest density, but often fine texture).
• Brown/Black: ~100,000 to 110,000 hairs.
• Red: ~90,000 hairs (lowest density, but often coarse texture).

3. Hair Porosity

Hair porosity is the ability of the hair to absorb moisture. The porosity of the hair is directly related to the condition of the cuticle layer. Healthy hair with a tight cuticle is resistant to moisture, while damaged hair with raised cuticles absorbs water quickly.

• Low Porosity (Resistant): The cuticle scales are tight, flat, and lie close together. Hair absorbs moisture slowly and requires more alkaline chemicals to raise the cuticle.
• Average Porosity (Normal): The cuticle is slightly raised. The hair absorbs moisture and chemical solutions normally, showing a good balance.
• High Porosity (Over-processed): The cuticle is highly raised, damaged, or even missing in areas. The hair absorbs liquids instantly but loses them just as quickly because it cannot retain moisture. High-porosity hair requires mild, low-pH (acidic) solutions and shorter processing times.

How to test (Porosity Test): Take a strand of dry hair from three different areas: the front hairline, the temple, and the crown. Hold the strand at the ends and slide your thumb and index finger down the strand toward the scalp. If the hair feels smooth, it has low porosity. If it feels slightly rough, it has average porosity. If it feels rough, dry, or catches easily, it has high porosity.

4. Hair Elasticity

Hair elasticity is the ability of the hair to stretch and return to its original length without breaking. Elasticity is an indication of the strength of the side bonds in the cortex.

• Normal Elasticity: Wet hair with normal elasticity can stretch up to 50% of its original length and return without breaking. Dry hair can stretch about 20%.
• Low Elasticity: The hair is brittle, dry, and snaps easily. It will not hold a curl or style and cannot withstand chemical treatments. If a client has low elasticity, you must recommend deep conditioning treatments and avoid all chemical services.

How to test (Elasticity Test): Select a few strands of wet hair from different areas of the head. Hold the strand firmly between your fingers and pull gently. If the hair stretches and returns to its original length, it has normal elasticity. If it breaks or fails to return to its original shape, it has low elasticity.

Wave Patterns

Wave pattern refers to the shape of the hair strand and is determined by the shape of the hair follicle as it grows out of the scalp.

• Straight Hair: Grows from a round follicle. The cross-section of the hair strand is round.
• Wavy Hair: Grows from an oval follicle. The cross-section is oval.
• Curly Hair: Grows from an elliptical follicle. The cross-section is flat-oval or elliptical.
• Coily/Extremely Curly: Grows from a strongly curved, flat follicle. The cross-section is a very flat, irregular ellipse.

Scalp Examination

A professional scalp examination must be performed before every service. You must check for signs of:

• Redness, irritation, or inflammation.
• Abrasions, scratches, or open wounds.
• Infectious diseases or parasite infestations.

Florida Law Highlight: Florida DBPR rules dictate that a cosmetologist must refuse service to any client who exhibits signs of scalp irritation, inflammation, open wounds, or communicable diseases. Performing services on an irritated scalp can cause severe chemical burns, infection, or worsen the client's condition.

Performing the Scalp Consultation

To perform a proper scalp examination, gently part the hair in several sections, beginning at the front hairline and moving toward the crown and nape of the neck. Look closely at the scalp under good lighting. Feel the scalp with your fingertips to check for any raised bumps, flakes, or localized tenderness. Ask the client if they are experiencing any itchiness, burning, or soreness. Document your findings in the client service card. If any abnormal scalp condition is observed, explain to the client in a professional, private manner that you cannot perform the service and recommend they consult a physician.