Hair and scalp diagnosis as a method
The systematic assessment before each treatment
A diagnosis is not a quick glance in the mirror but a systematic assessment you perform the same way each time. It is your professional insurance: when you have uncovered the hair and scalp's actual condition you can choose the right treatment dose product and time correctly and predict the result — rather than discovering problems along the way where it is too late to correct.
§The Five Parameters You Always Assess
A combination of mechanical measurement and trained eye
| Parameters recorded at fixed intervals | What you assess | Why it matters |
|---|---|---|
| Hair type and structure | Smooth, wavy, crinkly, crimped; thick/thin; density | Controls extraction, product quantity and expected fall direction |
| Condition | Healthy, dry, brittle, chemically stressed, broken | Determine if the hair can withstand chemical work and what care it requires |
| Porosity | How quickly hair absorbs and releases liquid | Determines color uptake working time and risk of uneven result |
| Elasticity | Does a wet hair strand stretch and spring back without breaking? | Lav elasticitet = svækket hår; advarsel før permanent/blegning |
| Condition of the sole | Dry, greasy, irritated, flaking, raw | Contraindications to treatment and may require referral to doctor |
§How to test porosity and elasticity in practice
You can feel porosity by running two fingers up along a dry strand against the scalp toward the root: rough and uneven feels high-porosity, smooth feels low-porosity. You assess elasticity on wet hair by gently stretching a single strand — healthy hair stretches and bounces back, while weakened hair stretches limply or breaks. Both take seconds and reveal what the eye doesn't see.
§Written consent and history
The diagnosis also includes what the customer tells you: previous color bleaching henna permanent and allergies and skin reactions. Henna and certain home colors can react unpredictably with professional products — always ask. Note the history in the customer file so it follows the customer to the next visit.
§From diagnosis to decision
When the five parameters are uncovered you translate them into a plan: which treatment which product which exposure time – and whether treatment should happen at all today. Heavily stressed low elasticity hair can mean that the right answer is to defer the bleaching and build the hair first. Being able to say a professionally justified no is also part of the diagnosis.
“The diagnosis is where the hairdresser earns their trade: the one who assesses correctly before treatment rarely needs to correct after.”