8.4 Consultation, Patch Testing, Strand Testing & Formulations

The Professional Haircolor Consultation

The client consultation is the most critical phase of any haircoloring service. It establishes client expectations, uncovers chemical contraindications, and evaluates the physical condition of the hair fiber.

Key Components of the Hair & Scalp Analysis

1. Porosity: The hair's ability to absorb moisture and chemical liquids.
   • Low Porosity (Resistant): Cuticle scales lie tight and flat. Requires longer processing time, heat, or higher alkalinity/pre-softening.
   • Average Porosity (Normal): Cuticle is slightly raised. Processes normally and evenly.
   • High Porosity (Over-processed/Damaged): Cuticle is lifted, broken, or missing. Absorbs color rapidly but fades quickly; requires a porosity-equalizing filler.
2. Elasticity: The hair's ability to stretch and return to its original length without breaking. Normal wet hair stretches up to 50% of its length; poor elasticity indicates compromised internal polypeptide chains, ruling out aggressive lightening.
3. Texture: Diameter of an individual hair strand (fine, medium, coarse). Fine hair lightens faster and takes darker color readily; coarse hair has a dense cortex and large diameter, requiring longer processing.
4. Density: Number of hairs per square inch on the scalp (thin, medium, thick). Determines product volume and subsection thickness.
5. Medical History & Scalp Health: Check for abrasions, open sores, dermatitis, or known chemical allergies. NEVER apply chemical color to an abraded or diseased scalp.

The Patch Test (Predisposition Test / Skin Allergy Test)

Under the United States Federal Food, Drug, and Cosmetic Act and Pennsylvania State Board of Cosmetology regulations, a Patch Test (also termed a Predisposition Test) is legally mandated for all hair coloring products containing aniline derivative dyes (paraphenylenediamine / PPD).

                   LEGAL PATCH TEST PROTOCOL (PA STATE BOARD)
┌─────────────────────────────────────────────────────────────────────────────┐
│ 1. Timing: Must be performed 24 to 48 HOURS BEFORE EVERY COLOR APPLICATION. │
│ 2. Test Locations: Behind the ear (mastoid area) OR inner fold of the elbow.│
│ 3. Preparation: Cleanse 1-square-inch area with mild soap and water.        │
│ 4. Mixture: Mix the EXACT color formula and developer to be used on client. │
│ 5. Application: Apply with sterile cotton swab; leave UNCOVERED & UNDISTURBED│
│ 6. Duration: Must remain in place for 24 to 48 hours without washing.       │
└─────────────────────────────────────────────────────────────────────────────┘

Reading & Interpreting Patch Test Results

• Negative Result (Normal): No redness, itching, inflammation, burning, or swelling at the test site after 24–48 hours. The cosmetologist may proceed safely with the chemical service.
• Positive Result (Allergic Reaction): Presence of erythema (redness), pruritus (itching), burning, edema (swelling), hives, or vesicular eruptions (blisters).
  • MANDATORY PROTOCOL: DO NOT APPLY THE COLOR SERVICE. Document the allergic response in the client record card and advise the client to consult a physician.

The Preliminary Strand Test

While a patch test checks the client's skin for biological allergic sensitivity, a Preliminary Strand Test evaluates how the hair itself will react to the chemical formula.

Objectives of the Strand Test

• Determines the exact processing time required to reach the desired target level.
• Verifies whether the formulated tone will properly neutralize or enhance underlying pigments.
• Tests structural integrity and determines if the hair is too damaged or porous to withstand chemical processing.

Strand Test Procedure

1. Select a 1/2-inch subsection of hair from a hidden area (e.g., lower crown or lower occipital).
2. Mix a small portion of the target color formula and developer in a non-metallic bowl.
3. Apply formula from scalp to ends, wrap in foil, and set a timer.
4. Inspect the strand every 5 to 10 minutes by wiping a small section clean with a damp towel.
5. Rinse, dry, and evaluate level, tone, and fiber elasticity under natural light.

The 5-Step Haircolor Formulation Strategy

Successful haircolor results require a systematic mathematical and chemical formulation method. Cosmetologists follow a 5-step diagnostic process:

Step 1: Determine Natural Starting Level (Levels 1 to 10)
   │
Step 2: Establish Target Desired Level and Tone
   │
Step 3: Identify Underlying Contributing Pigment at Target Level
   │
Step 4: Select Base Color / Tone to Neutralize or Enhance Undertone
   │
Step 5: Select Developer Volume based on required Lift or Deposit

Practical Formulation Scenario

• Client's Natural Level: Level 4 (Medium Brown).
• Target Goal: Level 7 Cool Ash Blonde.
• Lifting Requirement: 3 levels of lift (from Level 4 to Level 7).
• Underlying Pigment at Target (Level 7): Gold (Yellow-Orange).
• Formulation:
  1. Base Color: Level 7 Ash (contains Violet/Blue base to neutralize underlying Gold).
  2. Developer: 30 Volume Hydrogen Peroxide (supplies the 3 levels of lift needed).

Formulating for Gray Hair Coverage

Gray hair contains no melanin, meaning it reflects light transparently. If a fashion shade (such as pure red, copper, or violet) is applied alone to 50% or 75% gray hair, the gray hair will appear fluorescent, translucent, and mismatched compared to the pigmented strands.

Formulation Rules for Resistant Gray Hair

To ensure complete, natural coverage, a Natural / Neutral base (designated N or NN) containing a balanced blend of all three primary colors must be added to the formulation in proportion to the percentage of gray:

Pre-Softening Gray Hair

For extremely resistant, coarse gray hair with tightly compact cuticle scales, a pre-softening technique may be used:

1. Apply 20-volume hydrogen peroxide or an alkaline pre-softener directly to resistant gray sections (typically temples and hairline) without color pigment.
2. Process for 10 to 15 minutes to swell and open the stubborn cuticle.
3. Blot excess moisture with a paper towel (do not rinse), then apply the target permanent color formulation.