Hair Coloring and Lightening
Law of color
The primary colors are red, yellow, and blue; secondary are orange, green, and violet; tertiary are combinations. Complementary colors neutralize: violet cancels yellow, blue cancels orange, green cancels red. Level describes lightness or darkness (1 black to 10 lightest blonde); tone describes warmth or coolness.
Developers and products
Hydrogen peroxide developer volumes: 10 volume (3%) deposits tone with little lift, 20 volume (6%) lifts one to two levels, 30 volume (9%) lifts two to three, and 40 volume (12%) lifts three to four and is the most damaging. Temporary color coats the cuticle; semipermanent deposits without lift; demi-permanent uses a low-volume developer; permanent color lifts and deposits and requires a patch test 24 to 48 hours ahead.
Application
Virgin application: mid-shaft to ends first, then the scalp area last, because scalp heat accelerates processing. Retouch: apply to new growth only, then pull through the last few minutes for blending.
Lightening
Bleach lifts melanin; it does not deposit color. Use off-scalp application, check every five to ten minutes, and never store mixed bleach.
Worked example
A level 4 client wants a level 7 neutral blonde. That is a three-level lift; 30 volume gives two to three levels, so choose 30 volume with a toner to control warmth, strand test, and expect orange undertones that require toning.
Traps
Thinking 40 volume is always better. Applying permanent color over metallic salts. Forgetting the patch test. Mixing developer brands. Leaving bleach on the scalp longer than the label allows.