Hair Coloring and Chemical Texturing
Color theory and the level system
Primaries are red, yellow, and blue; secondaries are orange, green, and violet; complementary pairs (red/green, blue/orange, yellow/violet) neutralize each other. Levels run 1 (black) to 10 (lightest blonde) and describe depth, not tone. Tone is warm, neutral, or cool - two colors can sit at the same level and look completely different.
Developers and dye categories
10 volume (3%) deposits only and blends gray; 20 volume (6%) lifts about one level; 30 volume (9%) lifts two to three; 40 volume (12%) lifts three to four and belongs off the scalp. Temporary color coats the cuticle and shampoos out in one wash; semipermanent color deposits without lifting and lasts roughly four to six shampoos; demi-permanent uses a low-volume developer and lasts around 24 shampoos; permanent oxidation color lifts and deposits simultaneously. Patch test 24–48 hours before any aniline-derivative tint and always strand test.
Texture services
Alkaline perms use ammonium thioglycolate at roughly pH 9.0–9.5 to break disulfide bonds; the neutralizer (hydrogen peroxide) rebuilds them, so do not shampoo for 48 hours. Hydroxide relaxers run pH 12–14, require base cream, and are applied to new growth only every 6–8 weeks, followed by neutralizing shampoo. Never overlap relaxer onto previously relaxed hair.
Worked example
A level 6 client shows orange brassiness and asks for "ash." Reasoning: orange is opposite blue, so a blue-based ash formula at the same or one level darker neutralizes it; adding more ash pigment alone would not lift the depth. Strand test first, because orange signals underlying pigment exposed by lifting.
Traps that cost marks
Using 40 volume on the scalp; overlapping relaxer; perming over bleached hair; assuming semipermanent color lifts; skipping the patch or strand test.