Hair Care and Hair Services: Cutting, Styling, Texture, and Color
Cutting and styling
Four basic forms anchor cutting questions: blunt (zero elevation, solid perimeter), graduated (stacked elevation, builds weight), layered (elevation above 90 degrees, removes weight), and uniform layer (90 degrees all around). Know how distribution, elevation, tension, and overdirection change the result. In styling, roller size controls the outcome: a large roller makes a large, loose curl and less volume close to the scalp; a small roller makes a tight curl and more volume. Thermal irons and blow dryers belong on dry hair unless the manufacturer states otherwise.
Chemical texture
Alkaline waves run near pH 9 and use ammonium thioglycolate; acid waves use glyceryl monothioglycolate, sit near pH 7, and usually need added heat. The neutralizer rebuilds the disulfide bonds. Relaxers: sodium hydroxide (lye, high pH), guanidine/no-lye (mixed with an activator), and ammonium thioglycolate (thio). Relaxer retouches go on new growth only; product on previously relaxed hair risks overprocessing.
Color
Learn the level system: 1 is black, 10 is the lightest blonde - the higher the number, the lighter the hair. Developer strength sets the action: 10 volume deposits, 20 volume deposits with slight lift, 30 and 40 volume lift more and demand caution on the scalp. Know permanent, demi-permanent, semi-permanent, and temporary categories, and apply a patch test and strand test before color services.
Traps and rule of thumb
Trap: assuming a higher level number means darker hair. Trap: relaxing the entire strand during a retouch. Rule of thumb: if the hair has been relaxed, never overlap relaxer onto previously processed hair.