Colouring and Lightening
What the exam tests
This domain tests colour selection, chemical mixing, application, lightening and correction within safe limits. It expects accurate consultation, patch and strand testing, understanding of developer strength and the ability to neutralise unwanted tones.
Core rules
- Follow manufacturer ratios and processing times; do not estimate developer or colour. Common developers are 6 percent (20 volume), 9 percent (30 volume) and 12 percent (40 volume), each with different lifting power.
- Patch test before colour according to manufacturer instructions, usually 48 hours beforehand, and record the result. Perform a strand test when history is unclear or the hair is compromised.
- Identify the natural depth and underlying pigment. Pre-lightened hair exposes warm pigments: yellow is neutralised by violet, orange by blue, and pale yellow by violet-blue toners.
- Avoid overlapping on previously tinted hair; use root retouch techniques and keep product off the mid-lengths and ends unless refreshing.
- Metallic salts from some home products can react unpredictably with peroxide or ammonia; test and avoid lightening if the history suggests them.
- Protect skin, wear gloves and remove product thoroughly.
Worked example
A client is pre-lightened to a yellow-orange band and wants a cool blonde. Reasoning: orange needs blue and yellow needs violet, so choose a violet-blue toner at the correct depth rather than a high-lift tint. Shampoo, towel-dry and apply toner evenly, then check visually during processing. A high-lift tint would add warmth and damage already lightened hair.
Traps that cost marks
- Applying a 12 percent developer to tinted hair and expecting extra lift without damage.
- Skipping a patch test because the salon is busy.
- Using an ash toner that is too dark for the target depth.
- Overlapping colour and causing banding.