Uneven porosity and a requested colour change
A client brings a photograph of a pale, cool-toned colour and asks for the same result during an appointment booked as a routine retouch. The roots are untreated, the middle lengths were previously coloured, and the ends feel rough and break during ordinary gentle combing. The client cannot identify a product used at home several months earlier. The stylist has a manufacturer-authorized assessment method but has not yet completed it. A colleague proposes choosing a stronger developer and applying one mixture from roots to ends so that every area has the same exposure. The exercise supplies no permitted developer concentration, mixing ratio or processing time. The task is to reason about history, fibre differences, expectations and a defensible service decision without inventing a chemical formula.
1. Identify the material and consultation issues.
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The different regions have different histories and apparent integrity. Unknown prior products and fragile ends make one uniform process unjustified. Clarify the history, intended result and relevant precautions, assess using the actual compatible system and discuss achievable alternatives.
2. Does an arithmetic ability to mix a stronger product establish permission to use it?
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No. A calculation cannot establish compatibility, suitability or authority. Follow the system and scope, postpone or alter the plan when necessary, and do not promise a pale uniform result from the information supplied.