12.4 Colour Consultation, Patch & Strand Testing

The Colour Consultation

Every colour service begins with a consultation that combines hair analysis with the client's lifestyle and desired outcome. Skipping the consultation is the leading cause of colour mismatch and client dissatisfaction.

Hair Analysis Components

Lifestyle and Expectation

• Maintenance tolerance: high-lift and corrective services require more frequent upkeep; a low-maintenance client may prefer a closer-to-natural shade or a balayage with soft grow-out.
• Heat styling and sun exposure: both fade colour faster; a client who hot-irons daily needs colour-safe aftercare guidance.
• Allergies and sensitivities: flag for patch test.

Patch Testing

A patch test (also called a preliminary skin test) checks for allergic reaction to oxidative colour or lightener. The general rule:

• 24-48 hours before the service.
• Required for new clients, clients with known sensitivities, and clients with a long gap since their last oxidative service.
• Apply a small amount of the mixed colour or lightener behind the ear or on the inner elbow; observe for redness, itching, swelling.

A positive reaction (redness, itching, blistering) means do not proceed — postpone and refer the client to a physician if needed. Provincial regulations vary on exactly when a patch test is required; follow the stricter of brand instructions and provincial law.

The exam trap: assuming patch tests are "only for new clients." Many brands and jurisdictions require a patch test after any significant gap (commonly six months) since the last service, because sensitization can develop over time. A client who has coloured for years can still become sensitized.

Strand Testing

A strand test previews the colour result and processing time on a small isolated section of the client's actual hair, before committing the whole head. It is distinct from the patch test, which tests for allergy, not result.

When to Strand Test

• Before any corrective or high-lift service.
• When the client's hair has an unknown chemical history (henna, metallic dye, previous bleach).
• When the target is more than 2 levels lighter than the natural base.
• When porosity is uneven across the head.

How to Strand Test

1. Isolate a small section (about 1 cm wide) in an inconspicuous area — usually behind the ear or under the crown.
2. Apply the proposed formula to the section.
3. Process for the estimated time, checking every 5-10 minutes.
4. Note the result: the actual colour achieved and the processing time it took.
5. Dry the strand to see the true colour (wet hair reads darker).
6. Record the result on the client's record card.

The strand test is the only reliable predictor of how this client's hair will respond to this formula. Charts and timing tables are starting points, not guarantees.

Informed Consent for High-Lift and Corrective Services

High-lift blonding, double-process services, and corrective work carry real risks of damage, breakage, and unexpected results. Informed consent means the client understands:

• The process to be used (lightener, toner, remover, filler, recolour).
• The expected result and its limits (for example, "we can lift you to pale yellow, then tone to beige — we cannot get you to platinum in one session without breakage").
• The risks: breakage, dryness, scalp irritation, colour shift over the following weeks.
• The maintenance required: purple shampoo, toner top-ups, heat protection.
• The cost and time commitment.

A client who has given informed consent is less likely to dispute a foreseeable outcome, and the stylist has documented proof that the risk was discussed.

Recording the Formula

Every colour service record should include:

• Brand and shade (for example, Brand X 7N plus 7G).
• Developer volume (for example, 20 vol).
• Mixing ratio (for example, 1:1.5).
• Processing time (for example, 35 min, plus 5 min refresh on ends).
• Result (for example, "even 7N/7G, full gray coverage, no warmth").
• Any adaptations (for example, "added 5 g ash additive to control warmth").

The record lets you reproduce the result next visit and is the reference point for any future correction.

When to Refuse or Postpone

Some situations require refusing or postponing a colour service:

• Scalp abrasion, scratch, or irritation: oxidative colour and lightener on broken skin risks chemical burn and infection. Postpone until the scalp heals.
• Recent henna application: henna coats the cuticle and can produce unpredictable green, orange, or muddy results with oxidative colour. Wait until the henna has grown out or is removed — often a long process.
• Metallic dye buildup: metallic salts in some older dyes react with hydrogen peroxide, producing heat, damage, and off-colour results. Strip or test before proceeding.
• Compromised hair: hair with very low elasticity or existing breakage may not survive another chemical process. Refuse the lightener, suggest a conditioning regimen and a deposit-only refresh instead.
• Client refusal of patch test: if a patch test is required by brand or province and the client refuses, do not proceed.

flowchart TD
    A[Colour service requested] --> B[Consultation: hair analysis + lifestyle]
    B --> C{New/sensitive client or long gap?}
    C -->|Yes| D[Patch test 24-48h before]
    C -->|No| E[Proceed to service]
    D --> F{Positive reaction?}
    F -->|Yes| G[Do not proceed, refer to physician]
    F -->|No| E
    E --> H{Corrective or high-lift or unknown history?}
    H -->|Yes| I[Strand test proposed formula]
    H -->|No| J[Service]
    I --> K{Result acceptable?}
    K -->|Yes| J
    K -->|No| L[Adjust formula and re-test]
    J --> M[Record formula and result]

Common Faults

• Skipping the consultation because the client "always gets the same thing" — hair changes, products change, and the consultation catches it.
• Skipping the patch test for a returning client after a long gap — sensitization can develop over time.
• Skipping the strand test for corrective work — catastrophic colour failures are almost always traced to this omission.
• Proceeding on scalp abrasion or after henna or metallic dye — chemical burn or off-colour results.
• Not recording the formula — next visit you cannot reproduce the result, and any future correction has no reference point.