Chemical Services: Hair Coloring and Lightening
Chemical services: hair coloring and lightening
This domain tests color theory, developer choice, patch and strand testing, application safety, and the difference between deposit and lift. Expect questions that ask what a developer volume does, how to neutralize unwanted tone, and when to stop.
Color theory and levels
- Hair levels run from 1 (black) to 10 (lightest blonde). Each level is a degree of lightness or darkness, not a color name.
- The color wheel's complementary pairs neutralize: blue cancels orange, violet cancels yellow, and green cancels red. Underlying pigment is exposed when hair lightens.
- Eumelanin and pheomelanin determine natural depth and warmth; gray hair lacks melanin and may need a different formulation.
Developers and testing
- Hydrogen peroxide developers commonly come in 10 volume (about 3%), 20 volume (6%), 30 volume (9%), and 40 volume (12%). Higher volume means more lift and more risk.
- Always patch-test according to the product label and Florida rules before an aniline-derivative color; record the result. Strand-test to predict timing and outcome.
- Mix in a nonmetal bowl with the manufacturer's ratio; apply to clean, dry hair unless the label says otherwise; saturate evenly and time precisely.
Lightening and safety
- Lightener lifts natural or artificial pigment; it does not color the hair. Toner is used after lightening to adjust the final tone.
- Do not lighten over metallic salts, damaged or compromised hair, or an irritated scalp. Stop if the client reports burning.
- Never mix developers or brands unless the manufacturer allows it; never store mixed color for later use.
Worked example
A client at level 5 wants a level 9 blonde with no warmth. Reasoning: lifting four levels requires a controlled lightening process. The barber should strand-test, use the correct lightener and developer, check the underlying pigment, and tone to neutralize the remaining yellow or orange. A single application of level 9 color with 10-volume developer would only deposit, not lift enough, and would leave unwanted warmth.
Traps
- Thinking a higher developer volume always gives a better result.
- Skipping a patch test because the client has colored before.
- Toning before the hair reaches the target level.
- Applying color to an irritated scalp.